New build 5F2A pre > 6AQ7 concertina > cathode bias PP

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Phil_S
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New build 5F2A pre > 6AQ7 concertina > cathode bias PP

Post by Phil_S »

I just finished up what turned out to be a real nice sounding amp. I had expected something a little cleaner sounding and not quite this loud. This amp has 7 loud watts. Lots of recycled parts were used.

Every amp suggests a tune to me. This one wants the Hendrix version of Like a Rolling Stone. Now, if I could only pull that off!

Pictures posted. Comments welcome. http://home.comcast.net/~psymonds/5F2A+EL95PP.html
texstrat
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Re: New build 5F2A pre > 6AQ7 concertina > cathode bias PP

Post by texstrat »

Very nice point to point work. Now if I can get some of what you and Martin know to rub off on me......that would be good :D
mcrracer
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Re: New build 5F2A pre > 6AQ7 concertina > cathode bias PP

Post by mcrracer »

Just asking. Your schematic shows one thing, your pictures and data are on something different. Schematic shows 12AX7 in pre, Data and pix shows 6SL7 and a 6AQ7. Did you change circuits mid stream? Thanks. Both look like interesting amps.
azatplayer
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Re: New build 5F2A pre > 6AQ7 concertina > cathode bias PP

Post by azatplayer »

Very cool, love the recycling effort, been looking for something to transform myself!
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Phil_S
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Re: New build 5F2A pre > 6AQ7 concertina > cathode bias PP

Post by Phil_S »

mcrracer wrote:Just asking. Your schematic shows one thing, your pictures and data are on something different. Schematic shows 12AX7 in pre, Data and pix shows 6SL7 and a 6AQ7. Did you change circuits mid stream? Thanks. Both look like interesting amps.
Yeah, good observations. I intended the 6SL7 and 6AQ7 from the beginning. The circuit drawing program has limited tube selections. I'll see if I can relabel the tubes in the schematic. Also the power tube R/C for the cathode bypass is 180/47u, so I need to update the schematic anyhow.
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Phil_S
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Re: New build 5F2A pre > 6AQ7 concertina > cathode bias PP

Post by Phil_S »

azatplayer wrote:Very cool, love the recycling effort, been looking for something to transform myself!
If you can find an Eicor Model 15 (tape recorder amp), it make a near perfect donor for a 5F2. The iron is perfect and includes the choke. The tube complement is also an agreeable match, though I ended up going for the 6V6 over the 6K6. The chassis works, too, with a little bit of modification. Sorry, it seems I didn't document that one or I'd show some pictures.

I'm glad you like the recycling effort. I figure anyone who can throw money at a project can get it done. I don't think that's nearly as much fun. Part of doing this is therapeutic for me. It's as much the challenge of the project as enjoying the outcome.
mcrracer
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Re: New build 5F2A pre > 6AQ7 concertina > cathode bias PP

Post by mcrracer »

Gotcha, makes sense now. So, are the component values correct just the tubes mislabeled? I can fix the schematic on my end. I would like to build this one. That 6AQ7 is an interesting tube...diode and triode in same bottle. Gotta buy more tubes!!!!
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Phil_S
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Re: New build 5F2A pre > 6AQ7 concertina > cathode bias PP

Post by Phil_S »

I think I'd modify the tone stack values some. Not sure how, but there is too much treble. I think the rest is pretty good. I might raise R8 to 1.8K or 2K to lower the gain a bit.
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