George says it's good. Hammond 25CSE will also do the job:
http://www.diyaudio.com/forums/tubes-valves/100120-triode-champ-transformer-v-edcor.html
http://www.diyaudio.com/forums/tubes-valves/100120-triode-champ-transformer-v-edcor.html
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Ian (Gingertubes) cheap guitar amp.
I do design and build guitar amps as well as HiFi Amps and regularly attend Sunday afternoon jam (and some drinking) sessions with a few buddies.
My latest little amp has the other guys green with envy.
The Power Amp Section:
Push Pull 6V6 into a Chinese 8K Raa 10W Output Tranny designed for UL connected EL84 (but not using the UL taps) - from Mabel. Power supply is SS rectified.
AND
the best kept secret in guitar amps, a concertina splitter with a high mu tube. I use 6SL7 (56K anode and cathode loads) but a 12AT7 would be good too.
Eli - just use an El-Cheapo for the power section.
Oh - and I use "Baby Huey" style CCS blocks (100uF/63V Bypass caps) to bias the 6V6s. Rail is +320V
Preamp:
Is a Kevin O'Connor, London Power Standard Preamp (LPSP) but with 2 x 6SL7 (6N9P) rather than 2 x 12AX7. 2 Channel (Clean and Lead).
The Speaker Box - An old Sanyo HiFI Box, I threw out the 10" mid/bass and the tweeter and fitted a vintage Aussie Etone 10" Guitar Speaker I had on the shelf.
I've run it with Russian 6V6 which while not quite as good as the RCAs still sound damn good.
Cheers,
Ian
I do design and build guitar amps as well as HiFi Amps and regularly attend Sunday afternoon jam (and some drinking) sessions with a few buddies.
My latest little amp has the other guys green with envy.
The Power Amp Section:
Push Pull 6V6 into a Chinese 8K Raa 10W Output Tranny designed for UL connected EL84 (but not using the UL taps) - from Mabel. Power supply is SS rectified.
AND
the best kept secret in guitar amps, a concertina splitter with a high mu tube. I use 6SL7 (56K anode and cathode loads) but a 12AT7 would be good too.
Eli - just use an El-Cheapo for the power section.
Oh - and I use "Baby Huey" style CCS blocks (100uF/63V Bypass caps) to bias the 6V6s. Rail is +320V
Preamp:
Is a Kevin O'Connor, London Power Standard Preamp (LPSP) but with 2 x 6SL7 (6N9P) rather than 2 x 12AX7. 2 Channel (Clean and Lead).
The Speaker Box - An old Sanyo HiFI Box, I threw out the 10" mid/bass and the tweeter and fitted a vintage Aussie Etone 10" Guitar Speaker I had on the shelf.
I've run it with Russian 6V6 which while not quite as good as the RCAs still sound damn good.
Cheers,
Ian
It depends. I haven't built "custom" guitar amps in about 10 years, but the first step is to find out what the end user really wants. Often times he has a particular sound in his head, but can't explain it to you in an understandable language. How do you learn this info. In my case I get him to play every amp that I have in the room (which is currently none) and tell me what he likes and dislikes about each one. The next step is a road trip. We go to Sam Ash and the Guitar Center, and play every amp in the store with his guitar. I want him to show me the sound that he wants, and at what volume level he wants it at.
The speaker you show has a 125 watt power rating. and a 94 db sensitivity. That thing has just got to be loud with about 50 watts going into it. I would also bet that the sound would be rather clean with 5 watts or so to feed it. If the perspective owner wants a clean sound, then this speaker might be OK. If the guy wants distortion at something other than fully cranked, then a speaker tailired for that sound is needed.
El-Champo.
Bingo. Hence my question earlier about which genre music he/she plays. The basic requirements of a guitar amp aren't known without that tidbit of information, and will still probably be open to interpretation with that information; but at least it would narrow down the endless possibilities.
..Todd
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Another low cost transformer source.
Home - A Thermionic Webplace
I have bought several SE 10's from Matt at MPS, they are a bargain. The dual primary is handy and a 4,8,16 ohm secondary is a bonus.
His PT's work well, and are far cheaper than the equivalent Hammond.
Enjoy
Home - A Thermionic Webplace
I have bought several SE 10's from Matt at MPS, they are a bargain. The dual primary is handy and a 4,8,16 ohm secondary is a bonus.
His PT's work well, and are far cheaper than the equivalent Hammond.
Enjoy
I will second this recommendation. I have found the OTs to be good for guitar as well. Matt is great to work with too.
Tubelab -- Given your comment above, could you comment on using the 6W6 in a guitar amp? Hard or easy to overdrive? Recommended preamp/driver tube? Operating point (primary OT impedence)?? Have you every used the 6Y6 or 6K6 in this capacity? Thanks very much.
The 6W6 sounds pretty good but it's not a sub for the 6V6, with 300 volts at the screen it will die pretty soon. Check the screen max. voltage, I think is 165 volts.
Try a 6AQ5,
In all honesty, I think they have far more shimmer and chime than a 6V6 in a Champ style circuit. Bonus, you can pick up NOS pairs of 6AQ5's for $5-$10.00 on ebay.
Do a champ with a pair for a little extra punch, or just go SE for about 4 watts. If you use a fat piece of iron like the Edcor or MPS you will get plenty of bottom end.
Go Fancy and do an AA746 Blackfaced Champ circuit and have the added bonus of treble and bass control.
One of the first guitar amps I built back about 6 years ago was the AA764, I just loved that thing, Great living room volume, excellent for recording and took pedals well to boot.
In all honesty, I think they have far more shimmer and chime than a 6V6 in a Champ style circuit. Bonus, you can pick up NOS pairs of 6AQ5's for $5-$10.00 on ebay.
Do a champ with a pair for a little extra punch, or just go SE for about 4 watts. If you use a fat piece of iron like the Edcor or MPS you will get plenty of bottom end.
Go Fancy and do an AA746 Blackfaced Champ circuit and have the added bonus of treble and bass control.
One of the first guitar amps I built back about 6 years ago was the AA764, I just loved that thing, Great living room volume, excellent for recording and took pedals well to boot.
Hi Trout,
It's not the first time I read great things about the 6AQ5. Haven't try that one yet.
I'm curious, what do you think about the 6BQ5 in a Champ circuit versus the 6V6?
It's not the first time I read great things about the 6AQ5. Haven't try that one yet.
I'm curious, what do you think about the 6BQ5 in a Champ circuit versus the 6V6?
I am an against the grain kinda guy with 6BQ5/EL84's. I never cared much for them. Unless you are into the Marshall kind of thing, and do not mind pushing them to the edge to get the Marshall tone, PASS
The guys over on the AX84 site have loads of nice 6BQ5 based amps, they sound really good, but still different from the Fender tone.
6V6's Love Them, 6AQ5's Love them as well.
I have a clip someplace here from my old 6AQ5 amp, but I need to locate it and upload it again.
I have an old Kay 703 in the basement I have been meaning to convert over to a Champ style with a 6AQ5. This thing is one of those old death boxes without a PT. Picked it up out of a barn for $10.00?? I forget it was 3 years ago.
Donor amps like that are perfect starter projects, only 3 tube holes in the chassis.
For all practical purposes, the 6AQ5 is a 6V6 in a 7 pin mini package. So, your sentiments are completely understandable. The only significant difference is screen grid toughness. Watch your step, when using the 'AQ5.
Which version of the Kay 703 do you have? I've looked at 1 schematic where the rectifier is connected directly to the AC mains and a 2nd drawing, which shows a 1:1 isolation trafo between the 1/2 wave rectifier and the AC mains.
If you have the 2nd variant, Greinacher ("full wave") voltage doubling the isolation trafo may be all that's needed, for "Champ" B+. Half wave rectification, with its "standing" DC, puts a large strain on power "iron". The heft needed to take the "standing" DC could be put to productive purposes. Add a filament trafo and the magnetics set is complete.
If you have the model with the directly connected rectifier and the 1:1 filament isolation trafo, what's the tube complement? The drawing I have does not show parts values or tube types.
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I have the 703C First version, I am not going to post a link to the schematic because the last time I did, one of the mods got upset(rightfully so)
But schematicheaven.com has it listed under bargain bin.
Tubes 18DG6A, 60FX5, 36AM3.
Yep, I added a 1k screen resistor to that amp because I was on the edge there, hit a cord hard, and it would glow pretty solidly. 😀
But schematicheaven.com has it listed under bargain bin.
Tubes 18DG6A, 60FX5, 36AM3.
Yep, I added a 1k screen resistor to that amp because I was on the edge there, hit a cord hard, and it would glow pretty solidly. 😀
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Trout,
I got a better schematic for the Kay 703-C. That thing is FUGLY! The cabinet, speaker, chassis, and (perhaps) the O/P trafo can be salvaged. All the rest goes. The filament isolation trafo, with its 100 mA./18 V. rating has no practical use. 🙁 A 150 mA./12 V. part, with good HIPOT, could be of value in a safely executed series heater string design.
There are 3X 7 pin mini sockets available. Using SS rectified B+, something resembling a "Princeton" could be done with 2X 'AV6s and a 'AQ5.
I got a better schematic for the Kay 703-C. That thing is FUGLY! The cabinet, speaker, chassis, and (perhaps) the O/P trafo can be salvaged. All the rest goes. The filament isolation trafo, with its 100 mA./18 V. rating has no practical use. 🙁 A 150 mA./12 V. part, with good HIPOT, could be of value in a safely executed series heater string design.
There are 3X 7 pin mini sockets available. Using SS rectified B+, something resembling a "Princeton" could be done with 2X 'AV6s and a 'AQ5.
I tend to agree here. You want to get a cranked tone out of 6BQ5's, run a pair in push pull, and pick a tube that you can run hard. JJ EL84's or old Sylvania 6BQ5's. Want a Champ sound in a slightly smaller size the 6AQ5 works great. I have blown a few up though (but I have a few hundred). There isn't much room between a really cranked sound, and a red plate. There isn't much between a red plate and a hole in the glass either.
When I was about 14 years old I learned to make guitar amps out of old TV and radio parts. I used the 5C1 circuit at first but 6V6's weren't too common, so I tried anything that looked like it would work. I remember having great success with the 6BQ6GT's. An experiment I really need to repeat some day.
Oh Heck yeah its junk, LOL That is why it has been sitting on a shelf in the basement the past 3 years haha
I have a bunch of salvage junk to put in it, just lack of inspiration to bother with it right now.
I powered it up once, it sounded as horrid as the schematic looks, that is why I planned on making it into a champ style frankenamp.
The OT is about as small as those Triode champ transformers, it is mounted to the speaker frame ala Chicago style.
The cab I have is fairly clean, 2 tone and ugly enough to be cool in a weird way.
One thing I was told by several working musicians is that the cheapest quality speakers seem to sound the best in their amps. Maybe because they distort so easily?!? In any case, I've seen people buy some of the old 1040's and 1960's 8-12" radio cabinet speakers off ebay for $10 and $20 to put in their guitar cabinets. You might try that for a vintage sound?
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