Hey guys, I'm pretty much a noob here so I need all the help I can get. 😱
I caught the tube amp bug after buying my first tube guitar amp recently. I've been researching online how they work and how they're made and I'm very fascinated by it all.
On to the point of the thread, I've got laying around four 6l6 and three 12ax7 all in proper working order. It would be a cool little project If I could build a simple amp with them. I'm not concerned with a ton of power or even a high quality sound. Just something neat to sit on the table and use now and then when I'm in a retro mood.
I've got a basic (very basic) understanding of wiring, electrical components, and schematics. Do you guys think this is do-able? If so can you steer me in the right direction
I caught the tube amp bug after buying my first tube guitar amp recently. I've been researching online how they work and how they're made and I'm very fascinated by it all.
On to the point of the thread, I've got laying around four 6l6 and three 12ax7 all in proper working order. It would be a cool little project If I could build a simple amp with them. I'm not concerned with a ton of power or even a high quality sound. Just something neat to sit on the table and use now and then when I'm in a retro mood.
I've got a basic (very basic) understanding of wiring, electrical components, and schematics. Do you guys think this is do-able? If so can you steer me in the right direction
I have to say you are wrong right there. If you do it even half-way properly, you will find it sounds a lot better than your average cheap integrated. 🙂
Best thing you can do is start studying.
Remember the OPT's (Output Transformers) are the heart of a HiFi tube amp so if you want quality sonics it's not that cheap. In Guitar amps the OPT's don't have to be to the same std so they are less $.
You have to decide if you want PP or SE also. How efficient are your speakers, as that may decide that choice for you?
You have to decide if you want PP or SE also. How efficient are your speakers, as that may decide that choice for you?
I have designed and built a 5 Watts SE amp with this arrangement, cheap, reliable, compact and soundfull :
preamp section : a 12AX7 in SRPP circuit.
power section : a 6L6 (or EL34, or KT88, or any...) in cathode bias ultra-linear connection.
PSU section : classic rectifier 1N5408 diodes, 220µF caps and choke filter, 400-420V output circa.
Output Transformer : I used STS Millerioux HH25B (2500/2000tap/4-8-16/25W nominal power).
A+!
At this stage I'm not really interested in a high fidelity or high quality setup. I just want to cut my teeth on something simple, cheap, and easy to produce. If it sounds about as good as your average $20 FM radio/cd player from walmart I'll be just fine with that at this stage. In the future I may be interested in doing another project with more power and better sound quality.
I'm hoping to use a PP design.
That sounds like it's right up my alley! do you have any schematics you'd be interested in sharing?
Thanks everyone! 🙂
Hi RedBowTies88, welcome to the forum.
Maybe you have read our "sticky" thread on how to keep yourself safe from lethal voltages. A lot of the schematics described here use dc voltages in excess of 300V 😱
http://www.diyaudio.com/forums/tubes-valves/30172-safety-practices-general-ultra-high-voltage.html
How much are you wanting to spend on this (stereo) amp
Maybe you have read our "sticky" thread on how to keep yourself safe from lethal voltages. A lot of the schematics described here use dc voltages in excess of 300V 😱
http://www.diyaudio.com/forums/tubes-valves/30172-safety-practices-general-ultra-high-voltage.html
How much are you wanting to spend on this (stereo) amp
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I built this simple SE 6l6 amplifier and it is very enjoyable. You can find the schematic at:
Single Ended Tube Amp project
It calls for a 6SL7 on the front end but you can substitute a 12AX7 with no problems at all.
In fact I built mine with dual driver tube sockets so I can switch between the 2 tube types.
Single Ended Tube Amp project
It calls for a 6SL7 on the front end but you can substitute a 12AX7 with no problems at all.
In fact I built mine with dual driver tube sockets so I can switch between the 2 tube types.
Thanks for the warm welcome, I have read up on keeping myself safe. Last thing I would like to do is shock myself!😱
I was thinking that if I can use the tubes I have on hand and build my own chassis that I could hopefully 🙂o) get away with <$50 for a small mono amp. Again sound quality isn't really a concern so I was planning on using economy parts when possible.
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Hi Redbow,
50$ for a push/pull is maybe not enough. Try this link: EDCOR - GXPP Series Output Transformers for a nice Outputtranny
The 15 watters maybe OK and they have some nice cheap power transformers too.
Make the hightension with Diodes 4007 and try to get some electrolytics for smoothing.
You will need some caps and resistors.
I think in the end you will need maybe 150$ for all that crap.
Have Fun,
Hilmar
50$ for a push/pull is maybe not enough. Try this link: EDCOR - GXPP Series Output Transformers for a nice Outputtranny
The 15 watters maybe OK and they have some nice cheap power transformers too.
Make the hightension with Diodes 4007 and try to get some electrolytics for smoothing.
You will need some caps and resistors.
I think in the end you will need maybe 150$ for all that crap.
Have Fun,
Hilmar
I was thinking just a simple mono amp to play an ipod through into a single speaker.
If I could play guitar through it that would be neat too.
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With a $50 budget, if that's the final word ? - you will need to scrounge more parts to make something (or you should look for an old guitar amp on Kijiji/ebay).
As noted above you may yet need that $50 for some essential parts you can't easily find, especially the power supply filtering capacitors or tube sockets for the tubes you have.
You need output transformers. Can you scrounge parts from anywhere, a junk yard, or maybe pick up some old stuff from garage sales ? I'm thinking that worse case you can make do with a mains power transformer from some other piece of equipment. It might not sound great but it's within the spirit of what you are attempting (and you can always upgrade it). You'll nee a transformer with a secondary that has a centre tap (for push-pull) or two secondaries of the same voltage. Does this sound like something you could lay your hands on ? Other transformers might work if instead of a push-pull you make a single ended 'parafeed' - meaning a capacitor in series with your output transformer.
You need power transformers, to generate a B+ and for the filament heaters.
I'd hazard that what you can make will depend on what collection of transformers you can pull together.
As noted above you may yet need that $50 for some essential parts you can't easily find, especially the power supply filtering capacitors or tube sockets for the tubes you have.
You need output transformers. Can you scrounge parts from anywhere, a junk yard, or maybe pick up some old stuff from garage sales ? I'm thinking that worse case you can make do with a mains power transformer from some other piece of equipment. It might not sound great but it's within the spirit of what you are attempting (and you can always upgrade it). You'll nee a transformer with a secondary that has a centre tap (for push-pull) or two secondaries of the same voltage. Does this sound like something you could lay your hands on ? Other transformers might work if instead of a push-pull you make a single ended 'parafeed' - meaning a capacitor in series with your output transformer.
You need power transformers, to generate a B+ and for the filament heaters.
I'd hazard that what you can make will depend on what collection of transformers you can pull together.
What do the type of transformers I would need generally go for online? I have access to all kinds of junk stuff (hell my dad is a pack rat I've got tons of random things around at his place) so I may very well be able to source one for free.
Also I'm not dead set on it being a push/pull or the $50 price..but the closer the better
Also I'm not dead set on it being a push/pull or the $50 price..but the closer the better
Perhaps you could sell the 6l6's and a couple of the 12ax7s, use the cash to buy a donor amp. Look for a valve radio ( for a mono amp ) or stereo console. This would get you the mains transformer, output transformer(s) valve sockets and valves. Useful valves would be ECL82, ECL86 and EL84s. Not as powerful as the 6l6 but the dc voltage would be lower. This would make new electrolytic and coupling caps cheaper.
Well the idea is having a spare set around for my guitar amp in case I have a failure. And being as though I can't bias this particular amp (well, not without a lot of modification) I need to keep a whole matched quad instead of just 1. The 12ax7's though I would only really need to keep one.
I dunno, I'm well aware it's not ideal under any circumstances but it's what I have and it would be cool to have a little amp that shares tubes with my big guitar amp...
Tube sockets are pretty cheap and I have plenty of wire and solder laying around, how much do you think I would be into it for resistors and caps and one pot for the volume? I also have some 1/4 jacks lying around I can use for input/output.
Consider trying to use something like the 6AS7 in PP. Good results can be had using toroidal power transformers as output which can be salvaged. Use LM317 as bias blocks to keep DC out of the transformers. Such an amp runs well at 100V 100mA per triode which makes for a +B of just 130V after the bias is accounted for, and this can be created using salvged transformers.
Just an alternative to consider.
Shoog
Just an alternative to consider.
Shoog
Here is an interesting thread on a 12AX7 / 6L6 design that you may want to take a look at:
http://www.diyaudio.com/forums/tubes-valves/173431-6l6-12ax7-push-pull.html
http://www.diyaudio.com/forums/tubes-valves/173431-6l6-12ax7-push-pull.html
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