Hi there. First post and first forum I've joined. I live in south africa and have been building amps
for about ten years now. Early days were all about volume but since wife and two kids came along,
its been about getting tone at a decent soft sound. Decided to join a family of people that
understand what I am talking about since the are few around that understand valveamps, except for
the guy who winds my transformers and he is in a different town.
Well, I have been playing with different output valves that were not intended as output.
The tryed and tested 12at7, 12bh7, E80cc, but
I have had so much fun with a 6an8a pentode output. Very cool crunch at low level!
Designed (on paper only) a full pushpull amp with PI and reverb with 4 tubes.
Has anyone else done something similar?
At the moment it has only been SE, but still loud!!.
1 watts are still loud!!
Thanks.
Benj
for about ten years now. Early days were all about volume but since wife and two kids came along,
its been about getting tone at a decent soft sound. Decided to join a family of people that
understand what I am talking about since the are few around that understand valveamps, except for
the guy who winds my transformers and he is in a different town.
Well, I have been playing with different output valves that were not intended as output.
The tryed and tested 12at7, 12bh7, E80cc, but
I have had so much fun with a 6an8a pentode output. Very cool crunch at low level!
Designed (on paper only) a full pushpull amp with PI and reverb with 4 tubes.
Has anyone else done something similar?
At the moment it has only been SE, but still loud!!.
1 watts are still loud!!
Thanks.
Benj
low wattage
Most of the low wattage work in the past was for portable radios in the early sixties. Obviously saving battery life was the goal. The biggest watt sucker was the thermal vibrator used to create the B+ (plate voltage) in radios up to about 1960. Special 12V b+ tubes(valves in UK-speak) were developed, something about "space charge effect" or something. As soon as transistors got fast enough to do radio frequencies, all this work went down the tube. Most tube hobbiests now are plugged into the wall socket and don't worry about the heat. There have been long threads here about those 12V only tubes, but I can't remember the exact nomenclature to give you a search key.
People doing guitar effects for clipping distortion that are worried about battery life and tube cost (overdriving tubes burns them up) use zener diodes for clipping, or digital computer based effects.
Most of the low wattage work in the past was for portable radios in the early sixties. Obviously saving battery life was the goal. The biggest watt sucker was the thermal vibrator used to create the B+ (plate voltage) in radios up to about 1960. Special 12V b+ tubes(valves in UK-speak) were developed, something about "space charge effect" or something. As soon as transistors got fast enough to do radio frequencies, all this work went down the tube. Most tube hobbiests now are plugged into the wall socket and don't worry about the heat. There have been long threads here about those 12V only tubes, but I can't remember the exact nomenclature to give you a search key.
People doing guitar effects for clipping distortion that are worried about battery life and tube cost (overdriving tubes burns them up) use zener diodes for clipping, or digital computer based effects.
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Been trying to get some low voltage tubes but my supplier here doesn't stock them.
I made a 12v 12au7 pedal that works quite well. I am allergic to solid state.
Won't put diodes in to clip tubes. Clean valve tones are best. The ability to control
The clipping just by the pick attack. The best. Just like small tubes running on
High voltage. The idea of an EF86 and 6an8a pentode output is cool. And I really like
the tone of the little 6an8a pentode.
Thank you for the welcome
Benj
I made a 12v 12au7 pedal that works quite well. I am allergic to solid state.
Won't put diodes in to clip tubes. Clean valve tones are best. The ability to control
The clipping just by the pick attack. The best. Just like small tubes running on
High voltage. The idea of an EF86 and 6an8a pentode output is cool. And I really like
the tone of the little 6an8a pentode.
Thank you for the welcome
Benj
Hello Benjamin! From the words about pedals and clipping I take it you're a guitar amp guy rather than a hifi guy?
I'm a lurker here, very much still in the copy-paste school of amp design but diyAudio is full of godlike geniuses of vacuum tube technology and my knowledge is slowly advancing. To quote Isaac Newton, if I have seen further it is only by standing on the shoulders of giants.
I'm a lurker here, very much still in the copy-paste school of amp design but diyAudio is full of godlike geniuses of vacuum tube technology and my knowledge is slowly advancing. To quote Isaac Newton, if I have seen further it is only by standing on the shoulders of giants.
Hi Benjamin,
Ive been busy thinkin about the same problem for a while now.
A few things to consider:
- most distortion done in the pre stages of the amp sounds "hard".
- The sound I like the most is when the complete amp is overdriven, it sounds way smoother then the above or a pedal.
I think the sound of the power-tube in overdrive, combined with the saturated tranformer, gives the smooth distortion most people look for. (this is the real "tube" sound)
So I was thinking of building a normal SE tubeamp, but with an el 34, on a transformer of an el 84. Should give about 3-5 watts.
Then: after the output transformer connect an L-pad, before going to the speaker. There are L pads who can dissipate up to 100 watts, so the 5 watts shouldnt be a problem.
This way you can put the amp in overdrive, whith the smooth sound you want, but at the same time at a low volume.
I dont know if someone else build something similar...
I think my amp will be a Fender princeton clone, or something similar.
Building starts in a few weeks.
If you want I can update here if there is some progress.
Paul
Ive been busy thinkin about the same problem for a while now.
A few things to consider:
- most distortion done in the pre stages of the amp sounds "hard".
- The sound I like the most is when the complete amp is overdriven, it sounds way smoother then the above or a pedal.
I think the sound of the power-tube in overdrive, combined with the saturated tranformer, gives the smooth distortion most people look for. (this is the real "tube" sound)
So I was thinking of building a normal SE tubeamp, but with an el 34, on a transformer of an el 84. Should give about 3-5 watts.
Then: after the output transformer connect an L-pad, before going to the speaker. There are L pads who can dissipate up to 100 watts, so the 5 watts shouldnt be a problem.
This way you can put the amp in overdrive, whith the smooth sound you want, but at the same time at a low volume.
I dont know if someone else build something similar...
I think my amp will be a Fender princeton clone, or something similar.
Building starts in a few weeks.
If you want I can update here if there is some progress.
Paul
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The forum is excellent. Love getting replies. Yes guitar amps!!
Good to talk to people that don't just nod and smile and go that's nice.
Nothing against attenuators, but been trying to make an amp
that is complete without trying to squash the output.
There is a bit of tone sucking with this concept. Would really like
projects to be posted here. Dropping the voltage over whole amp works quite well
to reduce volume.
Its just that I have an interest in using little pentodes for quarter watt amps.
Pauldune: Remember to use a choke before the plate supply to remove hum.
Knowledge comes from others, wisdom comes from you own mistakes.
Get shocked, make crap amps. That we learn from!!
Good to talk to people that don't just nod and smile and go that's nice.
Nothing against attenuators, but been trying to make an amp
that is complete without trying to squash the output.
There is a bit of tone sucking with this concept. Would really like
projects to be posted here. Dropping the voltage over whole amp works quite well
to reduce volume.
Its just that I have an interest in using little pentodes for quarter watt amps.
Pauldune: Remember to use a choke before the plate supply to remove hum.
Knowledge comes from others, wisdom comes from you own mistakes.
Get shocked, make crap amps. That we learn from!!
This could be far in excess of your target then . . .
This is a one watt guitar amplifier, using a 12AX7 preamp valve, with a 6T10 output valve. The power supply uses two low-voltage transformers back-to-back, while the output is a reverb driver transformer.
Construction details are here: The Uniwatt Amplifier Revisited
Benjamin,
I have been looking at this web site just for interest.
Using Push-Pull EF86 Pentodes in a Low-Power Guitar Amp
I have been thinking about trying the circuit to see how it sounds. I built a fender champ a while back and used a 6L6 single ended it sounded very good.
It would be interesting to hear what kind of pedals you have made.
Regards
M. Gregg
I have been looking at this web site just for interest.
Using Push-Pull EF86 Pentodes in a Low-Power Guitar Amp
I have been thinking about trying the circuit to see how it sounds. I built a fender champ a while back and used a 6L6 single ended it sounded very good.
It would be interesting to hear what kind of pedals you have made.
Regards
M. Gregg
I've looked at that pentode press website. That is when I started playing with small pentodes.
I haven't hooked up a ef86 yet, but the 6an8a works well. Have some e83f's at home to try.
My voltage is abit high on my test chassis, so scared of frying some valves I've got.
I've built a 200v pedal, two stages. A 50v pedal, one stage with C follower (it was for an accoustic guitar)
And a 9v - 12v pedal.
Benj
This could be far in excess of your target then . . .
This is a one watt guitar amplifier, using a 12AX7 preamp valve, with a 6T10 output valve. The power supply uses two low-voltage transformers back-to-back, while the output is a reverb driver transformer.
Construction details are here: The Uniwatt Amplifier Revisited
That's a nice build man! Real PTP and not tagboard semi 'PTP'.
BenJ, I agree about one watt being loud, and personally I like the sound of a saturated output tube. But some do not and prefer the preamp crunch to output. I've built a couple of midget watters myself, with 5687, 6922, 6x3A5s, 6W6, and have a blast letting guitarists try one watt. But as soon as a drummer comes into the blend...ferget it.
Btw, this is mainly a HiFi forum, and u risk getting wierd looks, tho there is an instrument section, so no worries.
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I don't known anything about guitar amps but I've always been tempted to get an electric guitar for just the fun of playing around with it.
If you're looking at low voltage tubes all I've read about so far are using triodes at low voltages and the one I had my eye on is the 6DJ8 and Russian 6N23P.
p.s. welcome on board, it's good to have some threads that aren't just about hi-fi, guitar amps are most welcome in my book but I have much to learn. I don't even know what crunch is !
If you're looking at low voltage tubes all I've read about so far are using triodes at low voltages and the one I had my eye on is the 6DJ8 and Russian 6N23P.
p.s. welcome on board, it's good to have some threads that aren't just about hi-fi, guitar amps are most welcome in my book but I have much to learn. I don't even know what crunch is !
You might consider a 6AU6/A as they are much less expensive than the EF86 and probably more readily available.
I found this on another site that makes it look promising:
Push-Pull 6AU6 Build Thread. (warning: verbose!) - Telecaster Guitar Forum
I found this on another site that makes it look promising:
Push-Pull 6AU6 Build Thread. (warning: verbose!) - Telecaster Guitar Forum
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Bigun, I got a guitar from Grizley for $39.95 plus shipping that turned out to be pretty nice for a beginner guitar. With good strings it has held tune for the last week with my spending a half hour to an hour a day on it.
H7581 36" Junior Guitar - Green
H7581 36" Junior Guitar - Green
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