MUFF WIGGLER Forum Index
 FAQ & Terms of UseFAQ & Terms Of Use   Wiggler RadioMW Radio   Muff Wiggler TwitterTwitter   Support the site @ PatreonPatreon 
 SearchSearch   RegisterSign up   Log inLog in 
WIGGLING 'LITE' IN GUEST MODE

Looking for DIY Tube Resources
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2  Next [all]
Author Looking for DIY Tube Resources
luchog
Along with the regular Eurorack system I'm planning to start building later this year or early next (depending on how my Xmas goes, and how much overtime I can get at work), I'm also starting work on a DIY project. And by DIY, I mean seriously, old-school punk, Mad Max DIY.

I'm planning on building a series of valve-based modules for a really primitive synth, using as close to 100% scavenged parts as possible. I have a small pile of old radio and TV tubes, mostly pentodes and triode-pentodes, and one mystery tube which appears to be a triple-triode. Mostly pulls, but a few NOS, so at least a tiny number are guaranteed to work, and I've found spec sheets for nearly all of them.

I'm not looking for anything as clever and complex as the Metasonix stuff (which I plan to use as the backbone of my Eurorack), I'm looking for simple, primitive, noisy, crappy stuff that no one in their right mind would use. Utterly basic VCOs, VCA, and maybe even VCFs if I'm lucky.

I'm finding some resources online, but most of which expects that I'll have a solid knowledge of tube-based electronics which I certainly do not have (I have some small amount of solid state knowledge, but nothing I've touched for about 25 years). Something with guidelines I can use to tweak for bog-standard radio tubes that most people wouldn't really consider using for audio.

And before anyone tries to tell me that this is stupid and there's no way I'll pull it off; believe me I'm fully aware of how stupid and practically guaranteed to fail this is. That's kind of the point, really.
luchog
mispost
decaying.sine
Check out https://www.cgs.synth.net/ There is a tube page.
av500
luchog wrote:
I'm finding some resources online, but most of which expects that I'll have a solid knowledge of tube-based electronics which I certainly do not have (I have some small amount of solid state knowledge, but nothing I've touched for about 25 years). Something with guidelines I can use to tweak for bog-standard radio tubes that most people wouldn't really consider using for audio.


maybe the lack of "insert your tube here" type of resources is a hint that you should maybe do some research on your side first wink building with tubes is not hard, in many ways I even find it simpler than with solid state, but nevertheless you should know what you are doing.
Graham Hinton
http://www.valvewizard.co.uk
luchog
av500 wrote:
luchog wrote:
I'm finding some resources online, but most of which expects that I'll have a solid knowledge of tube-based electronics which I certainly do not have (I have some small amount of solid state knowledge, but nothing I've touched for about 25 years). Something with guidelines I can use to tweak for bog-standard radio tubes that most people wouldn't really consider using for audio.


maybe the lack of "insert your tube here" type of resources is a hint that you should maybe do some research on your side first wink building with tubes is not hard, in many ways I even find it simpler than with solid state, but nevertheless you should know what you are doing.


Definitely no looking for plug and play, and I've been doing the research. What I'm looking for is some basic circuit designs with formulae for adjusting the component values to match tube properties. Something that will let me bash a box together in a month or so without having to spend four years on a home-study electronics degree.

Like I said, probably impossible, but I'ma give it a shot anyway.
PrimateSynthesis
There are mailing lists on yahoo and such that have uploaded documents in their archive sections. Yes, mailing lists. Because most of the people who know about tubes are more likely to tell people to get off their lawn, than post their latest meal on Instagram. Oatmeal isn't photogenic. But scans of old books can be extremely informative.

There is a bunch of information online about building tube amps and pre-amps. Most of it is home stereo. Some of it is pro-audio. However, the closest thing to synthesis is radio.

Regardless, the first thing you need to learn is how to build power supplies. As you are going to need voltages that work with the tubes you are using no matter what you are doing with them.

Remember, working with tubes is dangerous. Even when unplugged from the wall. Large capacitors can be deadly. Be very careful.
luchog
PrimateSynthesis wrote:
There are mailing lists on yahoo and such that have uploaded documents in their archive sections. Yes, mailing lists. Because most of the people who know about tubes are more likely to tell people to get off their lawn, than post their latest meal on Instagram. Oatmeal isn't photogenic. But scans of old books can be extremely informative.


I'm finding a few, but not many that are terribly relevant. I did find one that seems to provide some useful bits. You wouldn't happen to have links to one or more of those mailing lists? (I used to run mailing lists from Unix boxes, Yahoo lists don't scare me even if some of the people on them do.)

There is a bunch of information online about building tube amps and pre-amps. Most of it is home stereo. Some of it is pro-audio. However, the closest thing to synthesis is radio.

Quote:
Regardless, the first thing you need to learn is how to build power supplies. As you are going to need voltages that work with the tubes you are using no matter what you are doing with them.

Remember, working with tubes is dangerous. Even when unplugged from the wall. Large capacitors can be deadly. Be very careful.


Yeah, that's the part that I think will most likely kill the project. I used to do some high-powered solid state radio stuff back in my military, pre-get-off-my-lawn days, but don't seem to have retained much of that knowledge.
Laughing
I've seen a couple projects that make use of voltage for tubes at considerably lower levels than the 250-300 VDC that is so typically found in older applications. http://electronics-diy.com/class-a-12au7-tube-headphone-amplifier.php
av500
luchog wrote:

Quote:
Regardless, the first thing you need to learn is how to build power supplies. As you are going to need voltages that work with the tubes you are using no matter what you are doing with them.

Remember, working with tubes is dangerous. Even when unplugged from the wall. Large capacitors can be deadly. Be very careful.


Yeah, that's the part that I think will most likely kill the project. I used to do some high-powered solid state radio stuff back in my military, pre-get-off-my-lawn days, but don't seem to have retained much of that knowledge.


nothing like touching a 700V tube power supply, don't ask me why I know smile
fuzzbass
Be ready for a really big power supply, with most of it going to the filaments. Might need fans too.
Don T
Don't overlook space charge tubes, which are tubes that are designed to run with low plate voltages, as in 12V or less. A couple examples:

12U7 - A 12AU7/ECC82 designed to run with 12V on the plates, can take up to 30V plate voltage.

6GM8 - A 6DJ8/6922/ECC88 designed to run with 6V on the plates, can also accept up to 30V plate voltage.

12K5 - A tetrode designed for 12 - 30V plate voltage.
luchog
fuzzbass wrote:
Be ready for a really big power supply, with most of it going to the filaments. Might need fans too.


Yeah, that's pretty much a given. The more I poke at this, the more I'm leaning toward commercial power supplies like the ones Metasonix uses/recommends, instead of trying to cobble together my own. It breaks the spirit of the project, but is just more sensible if I want this thing to actually work.

Don T wrote:
Don't overlook space charge tubes, which are tubes that are designed to run with low plate voltages, as in 12V or less. A couple examples:

12U7 - A 12AU7/ECC82 designed to run with 12V on the plates, can take up to 30V plate voltage.

6GM8 - A 6DJ8/6922/ECC88 designed to run with 6V on the plates, can also accept up to 30V plate voltage.

12K5 - A tetrode designed for 12 - 30V plate voltage.


Unfortunately, I don't have access to any of those tubes at this time. And buying tubes really breaks the spirit of the project. Here's a list of what I have available so far. Some of these are obviously wholly unsuitable for any sort of audio project, but there are a few that may have interesting properties if I can figure out the right circuit for them.

Unknown 6CL8A Triode-Tetrode
RCA 6CL8A Triode-Tetrode

RCA 6GH8A Triode-Pentode (Metasonix uses this tube for one of their modules, so it's the most obvious candidate for my project.)
RCA 5GS7 Triode-Pentode
RCA 21LR8 Triode-Pentode

RCA 6SK7 (x2) Pentode (I've seen guitar amps online that use this tube, but haven't yet found a schematic that shows useful component values.)

RCA 6AU5GT Pentode
RCA 6BQ5 Pentode
Unknown 6GE5 Pentode

Sylvania 6DB5 Pentode

GE Compactron 17JZ8 Pentode

Adm 5U4GB Diode

Silverstone 4EJ7/LF184 Pentode

There's also a tube that appears to be a sort of triple Triode, but with no readable markings left on it I have no clue what it is.
av500
luchog wrote:

Yeah, that's pretty much a given. The more I poke at this, the more I'm leaning toward commercial power supplies like the ones Metasonix uses/recommends, instead of trying to cobble together my own. It breaks the spirit of the project, but is just more sensible if I want this thing to actually work.


Metasonix runs the tubes at "low voltages", not all tubes and all tube circuits you will find out there will work with that. check out:

www.valvewizard.co.uk/Triodes_at_low_voltages_Blencowe.pdf
http://www.junkbox.com/electronics/lowvoltagetubes.shtml

luchog wrote:
Unfortunately, I don't have access to any of those tubes at this time. And buying tubes really breaks the spirit of the project. Here's a list of what I have available so far.


Google each one, see if there are schematics, see how they might be adapted for your needs, check the power supply voltages involved. if you really want to get into tubes I would recommend you get yourself a suitable 250-300V power supply (does not need to have much power if you are not into building a tube power amp) and whatever you need for the heaters and breadboard a few standard circuits to get the feel for it.
luchog
av500 wrote:
Google each one, see if there are schematics, see how they might be adapted for your needs, check the power supply voltages involved.


Yeah, I did manage that part all by myself, which is why I'm sticking with commercial power supplies. Most of these run at higher voltages than the stuff Metasonix uses or Don recommended.

The problem isn't the tubes, it's figuring out the circuits to use them in. They're mostly radio tubes, so the performance characteristics are considerably different than audio tubes. From the research, they're mostly remote-cutoff tubes, unlike the sharp-cutoff mostly used for audio, and beam power tubes. Not much good for amplifiers from what I've been reading, but possibly useful as oscillators.
Don T
luchog wrote:

RCA 6GH8A Triode-Pentode (Metasonix uses this tube for one of their modules, so it's the most obvious candidate for my project.)
RCA 5GS7 Triode-Pentode
RCA 21LR8 Triode-Pentode


These can be used to build a VCO/VCA, control voltage input into the pentode. Also, I'm pretty sure the 6GH8A can be used in the gain stage of a power amp, look up the schematic for the Dynaco ST-70, if I remember correctly, the 6GH8 can be used in place of the 6199 (but not without rewiring the socket)

luchog wrote:

RCA 6AU5GT Pentode
RCA 6BQ5 Pentode


6AU5 is a common tube in radio receivers, can be used as a VCA.

6BQ5 is a GREAT output tube for a small power amp, either single-ended or push-pull. Look up the schematics for Magnavox stereo console amps.


luchog wrote:

Adm 5U4GB Diode


This will be the full-wave rectifier for your power supply, highly recommended for that purpose, but wouldn't try to use it for anything else. Also, do NOT touch bare-handed while hot! Dead Banana
luchog
Don T wrote:
These can be used to build a VCO/VCA, control voltage input into the pentode. Also, I'm pretty sure the 6GH8A can be used in the gain stage of a power amp, look up the schematic for the Dynaco ST-70, if I remember correctly, the 6GH8 can be used in place of the 6199 (but not without rewiring the socket)

6AU5 is a common tube in radio receivers, can be used as a VCA.

6BQ5 is a GREAT output tube for a small power amp, either single-ended or push-pull. Look up the schematics for Magnavox stereo console amps.


Cheers, that is exactly what I'm looking for. I'll have to pull the spec sheets for the 6GH8 and 6199, fortunately all that stuff seems to be easily available online.

Quote:

luchog wrote:

Adm 5U4GB Diode


This will be the full-wave rectifier for your power supply, highly recommended for that purpose, but wouldn't try to use it for anything else. Also, do NOT touch bare-handed while hot! Dead Banana


Yeah, that's a big space-heater sized bugger.
luchog
In case anyone is interested, I found what appears to be a useful resource for general tube stuff.

http://www.funwithtubes.net/
controlFreak
There is an old RCA book with a red cover in E-book form somewhere online... searching RCA tube book will probably get you to it.

pretty much the bible.
noizehack
I've found a bunch of tube circuits by just doing google images searches for things like "tube oscillator schematic" you aren't going to find ones that use your specific tubes probably, but you can also buy them at electronics salvage shops if you want to keep to your diy whatever.

also here: http://schmitzbits.de/vtvco.html
and here: http://www.schems.com/tubebooks.org/

take a look at the metasonix schematics here: http://www.cgs.synth.net/

I know you said you didn't want to make anything as complex as metasonix in your original post, but look at the metasonix tube vco or vcf next to a solid state vco or vcf, they are very simple designs.

if you can find old radio books at used book stores sometimes they have tube vco circuits in them, probably designed for high radio frequencies, but you could try changing values for lower frequencies.
plushterry
http://www.schmitzbits.de/vtvco.html



Don't know if you have seen this or not?
plushterry
damn, just seen noizehack has posted the same link above, doh
luchog
noizehack wrote:
I've found a bunch of tube circuits by just doing google images searches for things like "tube oscillator schematic" you aren't going to find ones that use your specific tubes probably, but you can also buy them at electronics salvage shops if you want to keep to your diy whatever.


For some reasons I hadn't encountered the schmitzbitz.de link in my research, so that's useful.

I had come across Eric's stuff on CGS already, and there's one in particular I'll probably use, with some modification, for one of my DIY modules. It looks simple enough and I should be able to adapt it for the tubes I have with a bit of research and trial and error.
fitzgreyve
I've just put a Valvecaster overdrive into euro, with CV control of gain via a vactrol - see the "DIY builds" thread (page 16)/

Spare PCB's available of anyone is interested.
crudbreeder
Bear in mind that much of the serious tube resources out there isn't about low-voltage stuff like eurorack or stomp boxes but rather about "real" tube gear running at 250-600 volts, which can kill you or burn down your house unless you _really_ know what you are doing.
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2  Next [all]
Page 1 of 2
Powered by phpBB © phpBB Group