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jaymanaa / Urizen's Amp Project

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I was waffling back and forth between EL34s or 6L6s for these outputs, when I noticed the acrosound circuit for an UL, Williamson using 807s. Now I'm thinking maybe 1625s would be cool. I'd have to do some chassis work to get 4 small octals (6SN7 and 6SL7) in place of the three nine pin tubes, but it's absolutely do-able. There's enough room in between the vents to enlarge the power tube holes to accept the 1625 sockets too. Has anyone here ever heard a 807 / 1625 tube first hand?:scratch2: Here's a picture of one.
 
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From everything I have read, 807s and 1625s can essentially be considered a 6L6 and can be subbed for a 6V6 in any schematic. They also seem to get consistently good reviews for sonic performance which I would suspect is mostly related to them looking nicer than a 6L6.
 
If you decide to go with the Acro schematic and 1625s, hunt down some 14F7s (12SL7) and 14N7s (6SN7) or 14AF7s (similar to a 14N7) and throw them in there to save future tube costs. 6SN7/6SL7s keep getting more expensive.
 
Also, if you follow Miles Power's schematic, which appears to be a nice one, the 6J5 can be subbed with a 14A4 to keep the 12.6v heater theme going if you choose the 1625.

Although, if you were going to be cramped for space for 4 octals, I doubt 5 will make that task easier.
 
Good ideas Dave :yes: I had figured on mounting a 4 amp 12.6VCT fil. TX underneath for the 1625s, and that leaves me with a buttload of 6.3. I have to simulate a load on the PS I have mocked up, but I think it will do ~450v. I was thinking if it's a little low on voltage I might get lucky and have one of the 6.3 supplies wired next to the HV winding, and be able to add it on (PT has no CT, and the PS uses a doubler). I'll check with my snooty client on the tube choices. You know how people can be.:D
 
jaymanaa said:
I'll check with my snooty client on the tube choices. You know how people can be.:D
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I'm surprised that nobody has chimed in with their listening impressions of this tube. I thought the 807 was "fairly" common in hi-fi, but maybe not so much. I think I may have to just build a channel on the bench and see. I really need to start doing things that way anyhow, so I can concentrate more on lead dress with the actual amp without the fear of maybe having to rip a bunch of stuff back out.
 
Jay, I've found very little info around the net about using these tubes for audio. Of course, the radio guys love them as transmission tubes. Then again, I've not read anything negative about them. As cheap and plentiful as they are (for now), I say go for it, even with Newman's recommendation.:D

Pak has done some builds around this tube, and from what I've read, it's one of his favorites.
 
Jay, I think the RH807 site has some subjective sound quality assessments. They are commonly thought of as one of the best sounding 6L6 relatives.
 
jaymanaa said:
Thanks for the links Micah. Am I reading that right, that the 22S39 is a 20W output? They look much bigger than that??:scratch2:
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Not to worry Jay, my outputs are Mcintosh MA 230 outputs, rated at 25-35 watts or so, no problem with 50-70 with the proper B+. SOMEDAY I would really like you to take a look at this amp, it needs minor adjustment.

Doors still open to hear the JBL Econowaves!

Russellc
 
Russellc said:
Not to worry Jay, my outputs are Mcintosh MA 230 outputs, rated at 25-35 watts or so, no problem with 50-70 with the proper B+. SOMEDAY I would really like you to take a look at this amp, it needs minor adjustment.

Doors still open to hear the JBL Econowaves!

Russellc
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I'm going to have to "make" some time to get up there. Here's what 8 coats of tung look like on that Santos. It's starting to get real purty.:D I think just a couple more will do it.:thmbsp:
 
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Jay, does tung oil harden like laquer? I need to fine a high gloss finish for my 6L6 amp base. How do you apply the tung oil? I like that way yours looks. Also, will it stay that shinny? Cheers.
 
djnagle said:
Jay, does tung oil harden like laquer? I need to fine a high gloss finish for my 6L6 amp base. How do you apply the tung oil? I like that way yours looks. Also, will it stay that shinny? Cheers.
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Yes

with disposable foam brushes

thanks

and yes:D
 
jaymanaa said:
I'm going to have to "make" some time to get up there. Here's what 8 coats of tung look like on that Santos. It's starting to get real purty.:D I think just a couple more will do it.:thmbsp:
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Wow, that there is good look'n! Nice job there, just beautiful wood work!

Russellc
 
Thanks Russell.

Hey Ken, here's the sockets and cap I sourced at AES. Both seem to be of excellent quality. I should have a schematic on paper by tomorrow night. I still have quite a bit of testing to do on the power supply though. I'm hoping to get enough B+ out of that TX so that these tubes will be able to push the OPTs to their absolute max, with very little distortion. From what I have seen/read, voltage is a very important aspect of making these tubes all they can be.:thmbsp:
 
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Man that tube looks just like the 6BG6G, the ones I ran at the fest a few years back. :thmbsp:
 
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