Vacuum tubes

>>1160937
It is obsolete, but it's fun.

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>>1160937
its not absolute still beying used all around world , there is even a company in my town that makes tubes and shipps almost all production to US, i think they even build another building in the last years.
so whats the point?
do you want build a tube amp?

hey guys I have an old piece of tube equipemtn that has no use anymore so i'm going to salvage the tubes and transformer. I know that I can just power the thing on and measure the B+ voltage to figure out the voltage and I can probably look up the 3 tubes (two penthodes and a rectifier) to figure out the minimum current of the heater, but is there a proper way to find out how much current I can pull?

I want to turn it into a tube preamp, so just one or two 12au7, the rectifier and maybe if I want to get fancy an OD3 for regulation* so I can probably just call it a day and build it without caring about the current capabilities.

*info seems a bit sparse on using VR tubes without building a complete multi tube powersupply

>>1160937
That's a really nice sound effect machine and amplifier combo you got there!

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>>1160937
>File: 2a.jpg
>tube amp
>not using a neon pilot lamp

What are some good places to salvage transformers for tube use from?

>>1161071
wind your own faggit

>>1161089
B-but where would I get a suitable transformer core to use? A toroidal core would probably consume the least space, but could I rewind like a microwave transformer or a transformer from an old AV receiver or something like that?

>>1161071
That is a hard one to answer as most have valuable materials to recycle so grab them when you find them.

>>1161071
Old tube scopes. Old tube televisions. Old tube radios.

For the tube radios check that you are not destroying one that is worth something

>>1160937
>Obsolete
Technically, no
>Superceded
Yes.

Some argue that they have a superior sound due to lots of second harmonic or whatever, but a transistor amp can be be voiced in a similar way and have superior specs and, arguably, better sound.

They sure look cool though.

>>1160971
I believe VR tubes can only be used in very low current circuits unless you use other tubes or a mosfet as a series pass regulator, but maybe someone with more experience can shine a light on this

>>1161179
>For the tube radios check that you are not destroying one that is worth something
Nice old TVs and scopes shouldn't be destroyed either.

>>1160937
so what is the appeal with tube amps? why do (people claim) they sound so much better than digital amps?

>>1161323
The type of distortion they produce supposedly sounds good.

>>1161071
find free organs on craigslist. Pull the amp out and just throw away everything else

>>1161315
0D3 is rated for 5 to 40mA. So, in the best case, you can get 35mA regulated output. In practice you'll get less, but even then, it should be enough to supply a small preamp.

>>1161323
In addition to what >>1161327 said, some people like to look at fire bottles. Pretty much every modern tube amplifier has tubes sticking out for that reason, unless it is a guitar amp.
Then there are people who just like old stuff for whatever reasons, like >>1161321.

1000 watt Phillips tube amp from the 50's.
https://www.youtube.com/watch?v=C3_-2fUm6y0
Real mad scientist stuff, and it will also double a furnace for your entire house.

>>1161321
Well I ain't going to put one of those behemoths in my workshop or livingroom

>>1161336
Got any tutorials on how to calculate the resistor for them? It all seems a bit confusing to me

>>1161346
Same idea as with Zener regulators. Just Google Zener regulator design.
Basically, you need to know the minimum and maximum expected unregulated voltage and the maximum load current in addition to tube's limits. The maximum series resistor value is determined by the minimum input voltage and maximum load current + tube's minimum current. The minimum series resistor value is determined by the maximum input voltage and the minimum load current + tube's maximum current.
The minimum input voltage is limited by tube's ignition voltage and you can't put a large capacitor in parallel with the tube. The datasheet gives the maximum values for both.

In principle you can get more than 35mA out of a regulator using 0D3, assuming the current draw of your load does not vary more than 35mA.

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>>1161349
im going to look into this during the weekend, thanks

>>1161344
Class-B 1000W power amplifier, driver: 2x EL34 as cathode follower to the final tubes dc-balanced, balanced input, three-phase connection star circuit 220 / 380V. Anode voltage: 3000V, 250mA anode current per end tube at full load, rest current 50mA.

Year of manufacture: 1955
Measurements: 52x69x58
Weight: 142kg

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Should of stocked up on these years ago

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>>1161495

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>>1161510

Thanks, I'll get started on that right away.
Gonna need to double the parts list so I can have dual channels.

Anyone know anything about those Chinese kits that claim to be copies of the Marrantz 7 or really expensive high end stuff like that? How do they sound?

I heard that they were based off of simplified circuits made in the 70s or 80s.

>>1162627
Often you get what you pay for (up to a certain level)

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>>1162627
I figure they're a good source of cheap parts for making prototypes / tweaking. I might buy a couple for the purpose.

It would be interesting to run tests on / take measurements of the transformers and run a couple stock amps through ARTA, I might do that just for kicks.

So far though I find the Chinese output transformers to be OK; I have a couple that are "Lee's" and "Tomiko" brand, both made in Hong Kong and they do well. Pretty important because that part is more or less the heart of the amp. With "clones" of the higher end amps, I'd be curious to know if they skimp on those because transformers are usually the most expensive part of the amp and they love to build to a cost.

For stuff I build permanently though Hammond usually are my go to, they're better and from a known brand with a good reputation. Some Edcor trafos are better still and then you can go nuts and buy Lundahl or Tango.

Caps for the power supply could be kinda dodgy too, I wouldn't use them in anything permanent, especially the electrolytics.

But in the end it's you pay your money and you take your choice.

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>>1161344
Are they supposed to be red-plating?

>>1161344
>xrays

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>>1163080
With some tubes they need to operate with a heated plate, can assist with gettering. You can read about it in the RCA transmitting tube manual.

OP from the last thread here, I took my 25% IMD 6080 POS headphone amp, and brought it down to 2.91% and the THD+N to 0.4%. I also discovered something else: tube rolling is legit.

Some types of tubes has inherently higher distortion even though they are the same "type" but different brand. I have a Sylvania Gold Brand 6SN7 that tested 5.76% IMD compared to a Hit-Ray (Japanese Raytheon) that came out to 2.88%. Worth noting, because some that are "shitty" brands actually test better for distortion in some cases.

People also love to say that a 6CG7 can swap for a 6SN7 with the required adapter...it can, provided you're willing to live with another 2% distortion right off the bat.

I was gonna design an amp with the gain and phase inverter stages with 6CG7 but I think I'll pass.

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>>1163103
Screwing around with supposedly "great" tubes...added another 1% THD in this case going from different types of 6SN7. Mind you I switch tubes and bias consistently as a control.

IMD shot of the amp in progress. ARTA kicks ass.

What does a tube do that regular transistors don't?

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>>1163110
Being honest, nothing from a hi-fi perspective.

However they are still used in microwaves, as well as large transmitters. For how long though, who knows.

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>>1163110

clipping of high amplitudes is softer, i.e. peaks are rounder and thus sound "warmer"

What's the cheapest yet reliable way of driving a nixie tube from e.g. an Arduino?

is it worth just getting some Chinese IC?

>>1163110

As >>1163258 stated, the distortion they produce is more pleasing than the clipping that solid-state amplification produces.

The thing is, the solid state amps, even cheap ones, can reproduce sound much more accurately, and modern microcontrollers are more than capable of emulating the characteristic tube distortion via DSP. Not to mention the efficiency gains.

At this point, they're just audiophile wankery, really.

>>1163264
russian drivers or a bag of MPSA42 or MPSA92 if that is your kind of thing

>>1163110
as mentioned better way clipping/distortion but for most people it is because they glow and look cool

Thyratrons seems like a safe (if you use xenon) alternative to mercury rectifiers, does anyone have any experience with them?

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>>1163826
Unless you really have to have the glow, don't bother. Mecury rectifiers put out significant amounts of UV.

There's an argon filled rectifier designed to replace the 866A mercury arc type called the 3B28 that you can use.

>>1163924
I'm in love

>>1163924
>3B28
3B25 also exists but no idea on the glow/gas filling

Is anyone actually making a tube probject right now?

>>1160943
people make vinyl players too
argument dismissed

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>>1164904
I've got 5 on the go.

PP headphone amp with "shitty" TV tubes. About to run distortion characteristics tests on that.

Another PP amp with 6SN7 for the gain and phase inverter stages. 6GK6 outputs to 5K tomiko toroidal OPT. B+ of 330V. Hoping to get 10WPC @ >3% IMD.

The other 3 are in design stages...A SE amp which I already posted the results of, a guitar amp I'm going to make (converting an old 30's radio) and looking into making a 6080 cascode amp or maybe another Mullard 5-20.

>>1165037
>Vinyl players
Post dismissed

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I found a nixie tube calculator but the keyboard is stuck. Can anyone tell me how to remove these slider knobs. Tried pulling them but they won't budge

For clarity sake, just because something still works doesn't mean it isn't obsolete. Transistors are cheaper, smaller, lighter, faster, and more robust. Thusly, tubes are obsolete. Cool as shit though.

>>1165273
Tubes are pretty damn hot anon

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>>1165273
Transistors are still on the fence in regards to things like large transmitters and magnetrons, where vacuum devices are still better.

I don't think "obsolete" is the right word, superseded is better since there are still a large group of enthusiasts involved and a large market still. There are places still making tubes, I can't believe the 6V6 has been produced for more or less 80 years and is still in demand.

Nitpicking but also solid state circuits are not very aesthetically pleasing from a circuit design standpoint but that's just me being silly. However I love clean point to point wiring.

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>>1165132
Probably, you'll need to take it apart all case, its keyboard isn't like a computer keyboard. I have one nixie calculator too, and it comes crazy when divides by zero kek.

>>1165546
That's some nice wiring. How do I git gud like that?

>>1165615
naahh I need to take off the knobs in order to get the keyboard out. else it is impossible to get the mechanics unstuck

>>1160937
Anyone who puts leds AND tubes in a device, or uses such products will go to hell. No exceptions.

>>1160940
Some applications in HF make still use of tubes.

But in general they are a waste of time.

>>1165633
So I can't use an LED optoisolator in a Fender amp trem circuit? I cant use LEDs to add diode clipping to a gain stage either? I don't wanna go to hell, anon. Teach me.

>>1165708
Make a tube trem.
There are enough regular big muffs in the world. Use a gz34 or mercury vapor rectifier for your clipping like a real man.

>>1160937
https://www.extremetech.com/extreme/185027-the-vacuum-tube-strikes-back-nasas-tiny-460ghz-vacuum-transistor-that-could-one-day-replace-silicon-fets

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>>1162627
>>1163061
Anyone has a link?
I wanna see how they look

>>1165726
But it is a tube trem, anon.

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>>1165625
Be patient and plan your build with pen and paper first.

Figure out your tubes, power supply and other components. When you know what you want, look at the component dimensions, think about what's a reasonable size and buy or build a chassis. From there, draw it out and use your head, I usually start with the power supply / power tubes and try to keep the signal path and preamp as far from any emf sources as possible.

Unfortunately it takes time and lots of revisions but it's worth it.

Just think of

T H E A E S T H E T I C

Tested out my pp tv tube amp, was not disappointed. Less than 0.6% THD and 3% IMD at full power which is ear splitting to be honest. Frequency response is great too, 6AN8A is an interesting tube, pretty linear.

No screens because I took none.

Anyone has a schematic for good headphone amp without a transformer?
There are dozens forum posts, but has someone actually built anything themselves?

>>1166346
http://diyaudioprojects.com/Solid/12AU7-IRF510-LM317-Headamp/

hybrid is easiest, otl is possible too

>>1166378
And no worries about output impedance

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>>1166800
That too. It's a great first tube project for a beginner who's curious.

It's still not quite "tubey" in the sense a tube amp is. Really the transformers are a big part of the reason why they sound so distinctive at times but it still sounds good and is plenty powerful. Small speakers are not out of the question.

Best thing about this circuit is it's flexibility. If one can procure 2 variable voltage supplies, it's amazing what can be used since you can vary plate and heater voltages. Standard it can use 12AU7 / 12BH7 / 12AT7 / 12AV7. 12AX7 / 12AZ7 / 12AY7 could be used by changing the pot to a higher value and bumping the voltage up. 6CG7 / 6FQ7 / 6BZ7 / 6BQ7 could be used with a 6V heater supply. Changing the socket then you can use 6080 / 6SN7 / 6SL7 or a pair of 6AU6 triode connected or whatever you like.

Note though that the higher the voltage, the hotter the LM317 and IRF510 get, if you're going to experiment with a higher B+ then make sure you heatsink the semiconductors. I tried using up to 30V but no higher as it got quite warm.

Removing the cathode bypass cap would improve the distortion but reduce the gain.

It would be an interesting exercise to use a HV mosfet and an LM317HV as the current source to bump the voltage up. Distortion does drop when the plate voltage is increased for the most part.

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So I emptied out an old tube scope and got 4 telefunken ECC88 and 4 HP branded ECC88, 2 ECF80, an EL86 and a 6BC7 out of it.

any good ideas for them? Most are very usable for audio applications but there are so many projects to choose from

>>1167152
Wtf amps has a buffer with a 12au7

>>1167152
seriously, sell them on ebay while they're worth something and buy cheap NOS, you'll double your stash.

they are good tubes but you know what? its not the tube that defines good sound, it's good circuit design.

>>1167771
why buy different tubes if I have quite suitable tubes already

>>1167814
because there's more linear tubes out there that cost nothing...NOS 12A(x)7 and similar are audiophool memes.

>>1167896
so what would you recommend?

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>>1168173
a 12by7 is cheap as fuck and would be excellent, a lot of TV tubes are very linear and have high bandwidth. 6AU6 triode connected is also good and more linear than a 12au7

HOWEVER, this said, if you don't have the ability to do tests on a tube to determine lowest distortion, maybe stick with those. at the very least they are worth money.

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i dug this thing out

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it's filthy dirty, rusty, tuning cap dial cord is broken and the pots turn like shit

i did the best thing possible for one of these and plugged it right into the wall and turned it on. nothing happened.

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at least nothing came on the screen so i guess i need a new tv tube??

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underside of this beast...notice how old the resistors are. i don't see any dates on the caps, the magic eye tube is dated 47 but since those are frequently bad i suspect it's been replaced along with the 6J5 and 5Y4

the speaker is an interesting combo of choke, electromagnet and speaker.

i have the cabinet for this thing, but since it was found in the alley by my bud i'm having second thoughts keeping it original. plan is to restore the receiver, build a new box and probably ditch the electroshitspeaker for a conventional PM unit and output transformer

as for the cabinet it's in nice shape, thinking about making and stuffing a guitar amp inside of it, i have a lone 3.4K OPT that's good for 50W

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if anyone's curious it's a canadian marconi model 170

the silly thing receives
538 to 1722 KHz
2220 to 7036 KHz
6920 to 22370 KHz

not very useful as it stands since am is pretty much shit and i cant get any shortwave here, although i'm curious now that i have this boat anchor. considering asking my landlord if i can string up an antenna + lighting arrestor on the roof

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Tube lineup: 6A8, 6J5, 6K7, 2 x 6F6, 5Y4, 6U5
Audio power: 3 watts / 12 in dynamic ls

my best guess for dating this thing is mid 30's judging on the components

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upon further investigation the latest dates i see are patents from 1933, the circuit is rather simple but still a superhet, should be interesting to get it going

what's laughable is the output stage is single ended 6F6 in parallel...

pic unrelated

>>1166378
>>1166800
How hard would it be to adapt this circuit for use as a microphone Preamp?

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>>1169125
depends...

easy way is just use a mic to line out preamp and build the amp as is

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>>1169961
very nice, did you build that?

e80cf looks like a very nice tube, the curves in the datasheet are quite linear.

build a similar amp with those in push pull and you will have a nice surprise. it's what i did and I couldn't believe the results albeit i used 6an8a

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bored, took some pics of tubes and my amp

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if anyone has a request i'll try to do it, i have a lot of weird tubes

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6336A

wishing i had a macro lens, i tried fucking around with a bunch of lenses i have but it's a pain

>>1170618
Just a pic I found

I do have some e80cf though

>>1170663
they look like excellent tubes

i wouldnt do single ended but the designer of the amp in the pic looks like they took some interesting steps...looks like CCS for both pre and power amps. still i like the sound of push pull better

>>1170618
Is that mono or stereo?

>>1170675
mono, turning it into a guitar amp and changing a few things in the circuit, like the 12a6 for 6v6, adding a bias pot and scrapping the riaa for a gain/presence control

apparently the transformers aren't great and I have an empty radio cabinet so i figure it would be a good way to make a couple bucks

>>1161323
>digital amps
You mean solid state I hope...

>>1161042
its probably a lowvoltage meme preamp with op amps and all.

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anyone have experience making a tube RIAA stage?

looking at the marantz 7c.
not sure.
looking for simplicity really.

here is my stereo that a finished a few months ago.

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>>1170697
i don't but made one with a pair of 5532 with good results.

http://www.angelfire.com/electronic/funwithtubes/Amp-Phono.html

there's a couple good examples, i built the solid state version in an afternoon and was pretty pleased.

>>1170671
my current plans:

OTL amp for my headphones based around a 6080 (love the look of that tube), I will probably take some design off tubecad or maybe make my own interpretation of the bottlehead crack.

DAC+ tube buffer/pre amp for my gainclone

maybe a cute little hybrid amp for my girlfriend


I do have three 10 amp 6.3v transformers laying around though....

>>1170697
is that the K something kit?

nice touch with the nixie tube

>>1170939
thank you.
yeah,its a kit from way back i finally put into a chassis.

>>1170698
I'll try the circuit with higher output level.
looking at retrofitting it into the enclosure of the previous subminiature tube riaa i have.
it sounded fine, but had issues with oscillation.

looking at how i want to build it, I'm worried about noise from the power supply since the levels are so minuscule.

I'll try to get DC heater supply and maybe a zener clamped anode supply.

>>1171068
DC heaters are a good move.

No need to hold the plate voltage that steady, just do another RC circuit at the end of your preamp...say 10k ohm and 22uf should be ok but you can juggle values to get the least hum.

>>1171136
DC heaters need to be clean otherwise diode noise will get you. DC elevated heaters are much easier to implement.

Any idea why he's determined to grid leak bias the second stage of the angelfire link?

>>1171190
I will need to regulate anyway.
6.3v rms rectified will be too much anyway.

done heater elevation before, want to try dc.
should be easy to implement since there is only about 600mA of heating here.

i think i'll just shunt a lm7805 with diodes on the referance lead.
has worked a treat in the past.

obviously there will be rectification and caps as well.

>>1171202
started on the riaa.
ripped out the submini riaa.
put in a proper IEC power connector.
drilled out mounting and holes for the power transformer.
drilled out holes for the sockets, not mounted yet.

I'm still playing around with how i will assemble this.
also scrounging around for caps.

when power is applied, but tubes are cold.
there will be 250v present but no bias current. meaning the decoupling caps see full voltage, right?

I got some rated 250v and some rated for 600v+
should be ok.

do the feedback caps need the same rating?

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>>1171872

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>>1171874

>>1171872
No idea what PT you're using, but you'll see full HT on the coupling caps until the tubes start conducting.

Any caps in the supply or tied to the plates are going to need to shoulder that voltage. Everything else sees pretty meager potential.

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>>1171882
yup.
if you look at the feedback network, the two caps in series will see about the same in total.

I suppose they all should be rated 250v or more.

>>1171910
also, i assume filtering is mostly done with the feedback network, not the decoupling caps

will 22nf work fine in place of the 20nf in the first stage?

>>1171872
if your transformer puts out 200VAC

200 * 1.414 = 282VDC~

if i were you, use 350V caps or drop the supply voltage with resistors, the amount of current drawn by the tubes won't drop the voltage enough to be safe for the caps rated 250v

>>1171917
22nf is fine, just a coupling cap and won't affect the RIAA network, still within 20%

>>1171875
Ebay has some nice transformer covers for 10-15 dollaroos

>>1172066
exactly, that's where i got that transformer.

>>1171940
the power caps will obviously be more than 250.
i got some 350 and 450 about.

I have a couple of huge ones.
one is 150µ 350v, as big as the transformer.
i want it to look neat so ill try to use the smaller ones first.

i simulated and found that a C-R-C-R-C seemed to work well.
22µF 3-5k as well as a bleeder on the middle cap.

I'll try AC heaters with elevation and some nicely shielded cabled before i mes with dc heating tbqh

>>1172094
>I'll try AC heaters with elevation and some nicely shielded cabled before i mes with dc heating

I built a Heathkit audio preamp years ago.
Heater wires were to be twisted tightly and slipped through a 'spring' before attaching.
Only one end of the 'spring' was grounded to chassis.

>>1172110
in my experience shielded cable is much more effective than twist.
built 3 guitaramps so far in addition to the stereo i mentioned.

grounding on one end is a given.
no groundloops allowed.

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>>1172094
wasn't sure if you were aware or not, my bad, but i suggest even the coupling caps are at least 350...i usually design for worst case like high line conditions and also to minimize long term failure. caveat: you might get away with 250v caps if you use a tube rectifier. 6x4 is cheap and plenty for this application.

if you use ac heaters, you may need to wire in a pot for hum cancellation. you may not need to elevate the heater voltage but if it helps, you can leave the pot and still have the benefit.

btw, a really cheap source for mylar coupling caps is ebay, i get those 200pc 20 value deals and they're $25 shipped. rated 400v too which is good enough for most tube circuits. i bought a couple and now i rarely wanna pull parts, not worth the time.

when it's done let us know how it sounds, i built his op amp version and was very pleased. i might give this a go myself.

also there's a tube that's similar to the 12ax7 but has a much lower noise rating and heater to cathode leakage is quite low which will make things easier. i'll see if i can dig out the info, i can't remember the type.

oh and if you really want good filtering...

>>1172136
that is such a cute little amp!

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>>1161508
thats my nixie clock

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>>1172143
it was hell to put together and looks like a bomb went off inside. still, it's distortion measurements were pretty acceptable with 6an8a...going to try 6bh8 just gotta wire it up and bias the tubes.

>>1171875
what kind of box is that, looks very useful for headphone amps

>>1172136
is that enclosure plastic?
>if you use ac heaters, you may need to wire in a pot for hum cancellation. you may not need to elevate the heater voltage but if it helps, you can leave the pot and still have the benefit.
i did elevation and humdinger on the first amp i built.
with elevation the humdinger pot is pointless really. as the 6v ac is now biased to 60v or more DC.
I found elevation to be much better.

>also there's a tube that's similar to the 12ax7 but has a much lower noise rating and heater to cathode leakage is quite low which will make things easier. i'll see if i can dig out the info, i can't remember the type.
I'll use 6n2p, functionally equivalent to 12ax7 except a few points.
slightly lower gain factor
runs on 6v only and pin 9 is a shield between the triodes.
the real reason i use it is because its cheap on ebay and i have a few to spare.

>>1172243
diecast aluminium box.
its basically an oversized stompbox.

>>1161042
kkk

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Warm and crunchy, like a good tube amp... tubular

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>>1172285
yeah...big mistake, don't use plastic with a tube amp. the strength and workability are excellent but it has absolutely no shielding.

also sounds like you can switch that out for 6FQ7 but that will drop the gain a lot. there's also 6bz7 as well. might be interesting to try a couple types and see how they perform.

i do find my opamp based preamp has more gain than i need, would be nice to swap them like tubes.

maybe this weekend i'll pick up a project box and throw the tube version together as well. i wonder how it sounds.

>>1172672
Kt88 something?

>>1172672
>maybe this weekend i'll pick up a project box and throw the tube version together as well. i wonder how it sounds.

you might be finished before i am.
lots os school shit going down this month

mounted the sockets today, experimented a little with the components.
i dont have any strips handy so i kinda want to mount everything in the sockets.
that will interfere a little with the star grounding, but since there is now 'power' here I doubt it matters.

the sockets have tube shields, si i hope that will help with noise.
but i think the only source i should worry about is heater noise.

ill try shielded and elevated AC first, because DC is a bit of a pain.
smoothing ish 700mA dead flat needs a bit of filtering.. and thid box is small.

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>>1172780
that depends, i have a lot of projects i should finish first. maybe if i feel like doing it, not much motivation since my phonograph is being a piece of shit...and it is really. either way, we can make notes and comparisons.

any pics? i may take a pic or two of my pp headphone amp inside. it's terrible. you could always ground components to a heavy gauge copper wire secured to the chassis, it's what i did and i had no problems with grounding.

shields go a long way for reducing noise, especially things like fluorescent lights. i think you'll be ok with the heaters, just tightly twist the wires with solid core 18awg and keep them far from the signal path.

yeah i know what you mean, i avoid it if possible and if i build an amp with a phono stage i usually try to run a heater or two through the power stage cathodes, altec did it that way to somewhat set bias on the 353a i have....-24V iirc

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>>1172727
6336a...to some maybe a waste of time compared to kt88. this tube draws 5A heater current, whereas a kt88 is way easier to find and a pair would draw less in heater power and provide more power.

>>1172951
dual power triodes?
heating that shit must be a bitch.
do you use a separate heating transformer?

>>1172951
I have three 10 amp 6.3 volt trannies... please tell me more about this amp

>>1172951
The amp in your picture, can you tell me more about it / schematics / more pics

I have a bunch of 6080s laying around

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>>1173040
Only 5.6A roughly, I used a 6.6A 6.3V transformer for the heaters and then another transformer to step the voltage up to a doubler. 6336A single ended is just as bad...5A filament

>>1173255
it was a waste of time and you're better off using other tubes

>>1173292
it's not worth building...huge power supply for just a couple watts

>>1173556
I love the looks though

>>1173597
it's pretty simple to build, 470ohm pot with a 1000uf bypass on the cathode, 1.6k output transformers.

phase inverter is cathodyne 47k on the plate and cathode

driver stage is 47k on the plate and a 1k pot to set grid voltage.

really nothing special, i didn't see the sense in an amp that sounds like shit but looks good so i scrapped it

>>1173600
But how bad can it sound, not much worse than no amp I suppose. And people always rave about the bottlehead crack which also uses the 6080

>>1173670
well, try it for yourself and see, i'll try to draw a basic schematic for you to build

just be warned: you need a very capable power supply and be prepared to fuck with it a lot...i can't describe the sound well but suffice to say it's not great to listen to for long...mind you this is probably because i used shitty transformers

i think the crack is single ended which i've had success with once i found suitable transformers. best case i could get with 6080 SE was 3% IMD...not bad.

up to you, if it really is your thing i'll draw something up for you.

>>1173690
not necessary, I want to make something without output transformers. I was just curious but I don't want to make you spend time on drawing that stuff up

waiting for caps for the RIAA...

I'm also making a el34 power stage for a guitar amp. using fixed bias for the first time.
there is separate winding for bias voltage on the power transformer so why not.

bias voltage will be rectified and reference negative to ground, with a pot to adjust + capacitor etc.
is it safe to test it with tubes the lowest voltage(cutoff) and slowly adjust closer to gnd and measure current as i go?
I'm afraid of starting it with a too high bias and hurting muh tubz

this wont be with a speaker, but a dummy load.

i prolly wont bother using fixed bias for the preamp tubes and phase splitter though.

>>1160937
>>show the world that this obsolete tech is not obsolete yet
>being enough of a pretentious faggot to use vaccum tubes for anything other than nixie
>not being willing/edgy enough to make your own germanium/silicon transistor
You're pathetic.

>>1174906
>>being enough of a pretentious faggot to use vaccum tubes for anything other than nixie
nixies aren't vacuum tubes moron, now fuck off.

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>>1161336
>fire bottles

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>>1174906
>being enough of a pretentious faggot to use vaccum tubes for anything other than nixie

tubes are still very useful in high power applications like transmitters and guitarists love them in their amps because of their non linear distortion characteristics and reluctance to hard clip. that's just a preference in the latter case; they perform a function that is desired and popular so i can't see how that's pretentious.

as for nixies? they just look neat and are very limited in function, their intended use to display limited information. that's boring, it narrows your project scope down a ton. a regen receiver isn't based around the function of a nixie, nor a transmitter, or a radio.

i highly recommend you think before you write and get an education. there you will read books and learn things so you can prevent yourself from opening your mouth and spouting dumb crap. people will like you more.

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>>1174783
right on, i'm converting a heathkit a-7 to a guitar amp and mounting it in that old radio chassis. only problem is that's like starting two projects...but i am curious to get that radio going and build a good antenna. my current shortwave radio is a portable sony and it sucks.

>is it safe to test it with tubes the lowest voltage(cutoff) and slowly adjust closer to gnd and measure current as i go?

absolutely fine, but it's only necessary to start at -50. before you power the amp on, take out the power tubes and rectifier tube, switch on, set the bias voltage you are comfortable with, replace tubes and measure current. an accurate 10 or 1 ohm resistor with a panel meter wired in parallel makes a really convenient bias control

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>>1175218
resistor in series with the cathode, derp. one coffee isn't enough for this shit first thing in the morning

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>>1173956
by the way, i found this:

http://www.megahertzaudio.it/otl_con_una_6080.htm

if you are crazy like me and have a ton of 6080 as well you may consider building this:

http://www.bonavolta.ch/hobby/en/audio/6as7_2.htm

check out that power supply!

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here's the rest if some of you are lazy

if i built this, i'd add even more shit into the mix and use mecury rectifiers because why not.

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2nd section of the power supply

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final

i wonder what the specs are on the distortion as well as the damping factor.

>>1160937
Over Clocking Pentium E5400 on P5Q-EM to 3.6 Ghz
https://youtu.be/8HTVson6VPQ

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>>1175216
>tubes are still very useful in high power applications like transmitters
Well, yeah, sometimes. They're used in X-ray equipment, too, plus in some other niche applications.
This thread, however, revolves around using them to amplifying audio at power levels where the tubes have no technical advantages.

>guitarists love them
There aren't many guitar amps ITT. His stereotype applies to this thread pretty well. Whether the stereotype is justified is another matter, though.

>display limited information. that's boring
Maybe, but the looks is a large part of the attraction of tube audio amps.

>>1175218
>>1175219

i guess i could do that.
i know what current I'm comfortable with, not bias voltage exactly.
ill figure it out.

1ohm in series are in the plan.

Very nice protosetup btw.

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>>1175245
i don't appreciate generalizations, i 'wasted' 2 years studying tubes specifically and now it's making me money. i don't do it because it's "pretentious", i do it because it's a fun hobby that happens to involve a way to turn a profit.

>Maybe, but the looks is a large part of the attraction of tube audio amps.
heh, most people into boutique amps would think my altec is ugly, you can't see the tubes with the covers on. for me it's the tone, sure, it's nowhere near as 'clean' as my lm3876 amp but it sounds pretty good.

in the end, it's electronics, it's a fucking hobby. solid state or tubes, its way better than wasting your time playing vgs for no benefit

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>>1175286
look at a datasheet for an el34 and draw a load line, it will help out in picking an operating point. just plot your plate voltage and divide that by the impedance to plot the current, then draw a line between the two points; it will give you an idea of what the cutoff voltage will be close to

>>1160937
What possible use could there be for a vacuum tube?

Asking for a friend.

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>>1175582
As an audio amp? See, for example, the replies to >>1163110.

In an overly broad sense? They can still be cost-effective when very high output power is needed. There are also special stuff like photomultipliers, where the semiconductor equivalents aren't directly competing with them, at least not in all applications.

>>1175680
>1000 amps
>30 mhz

holy crap.
how do they keep parasitics so low on such a huge tube?

>>1172146
>shitty tubes where 5 is an upside down 2
>mcu
>driver ic, not building your own

casual.

>>1175221
>http://www.bonavolta.ch/hobby/en/audio/6as7_2.htm
straight off mains OTL amp, that guy doesn't fuck around

>>1175794
woops missed the tranny, nevermind

>>1175223
use a tube voltage reference while you are at it

>>1165040
>being disgusted at applying modern naming convention to obsolete relics.
Cassette player
VHS player
LaserDisk player
CD player
DVD player
Bluray player

...

Oh, because he called a record a vinyl. that's not a valid reason to disregard his post.

Just something that flew through my mind. It is technically possible to decide audio with dekatrons and vacuum tubes. A contrapion like that would be pure insanity while nowadays a grain of silicon does the same.

Electronics evolve so fucking fast it's unbelievable

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>>1176999
>to decide audio with dekatrons and vacuum tubes
Huh? You mean some kind of stepping source select switch? Yes, but a more convenient "period-correct" solution would be a stepping relay.

>>1165639
And you know this, how?
I've been a user of valves for years, in radios, amplifiers, there is always an application for them, but the folks these days don't know how to properly use them, but all say they know them.

>>1174921
>nixies aren't vacuum tubes.

Fuck you, you're obviously too young to be in this thread.

>>1175743
>how do they keep parasitics so low on such a huge tube?
Ceramic tube filters

>>1177193
Have you any other justification for that than personal preference?

>>1163264
The cheapest way parts wise is a multiplexed anode/cathode drive. 10 low side drive transistors and one high side per tube, scan the digits in firmware. The easiest is the Russian drivers. Using dedicated low side drivers with anodes wired on is a middle ground. Depends how much your time is worth.

>>1177196
really?
i've used nixies and tube quite a bit.
both seen here in my stereo.
>>1170697

thing is, nixies are cold cathode gas discharge tube.
its filled with mostly neon, not evacuated.

post your diy amps projects or be silent.
nixies belong in another thread.

>>1161345
but you let your wife in the living room

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cooked this greasy thing up, already getting stations even though my coils are shit

>>1178197
>one tube
Regenerative or a crystal set with an amp?

>>1177764
He's probably referring to the fact that ye olde tube books weren't usually this anal about the separation of the gas filled and vacuum types.

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>>1178240
regen, tunes am and sw up to 16m i think

originally was gonna build a crystal set but went this route

>>1161323
The warmth and organic sound does it for me

>>1161508
Should have*

>>1178197
Neat.