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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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In Reply to: Re: need to see a schematic posted by groverg on December 25, 2004 at 18:43:56:
Thanks for posting the schematic Grover. I have taken a good look at it and the differences I see are as follows:
1. The decoupling caps from the plates of the 6n7 and el34 are 3x47/350 and 3 x 100/450 instead of both being 3x330/450.
2. The plate resistors of the 6n7 are 2 24k/2w in series. For the el34 I put 7.5k, 4.3k and 3.01k resistors in series. All are at least 20W.
3. The rating on the 125ese is only 80mA I believe.
4.At the moment I do not have the 100ohm/2w resistor on the filament of the 845. I wanted to try it without it first.
5. My B+ PS is tube rectified. It has a 5R4GYA and is CLC with 15mfd, 15H and 40 mfd. I have been using this same set with a 5AR4 for a long time with no trouble at all.
6. The filament voltages are all AC and come off the taps on the PS transformer. The 6.3 goes first to the 6n7 where one leg is grounded and then I take it to the el34 from there.
7. I should probably mention that the whole bread board is put together with clip leads. I have had no problems with that so far, but it did give me some pause do to the higher B+.
8. The bias supply is a small tranny run off a small variac. I have N4007 diodes with the bar end attached to the tranny terminal and a 100/450 cap with the + end grounded. I adjusted the variac to get - 170 vdc.
While you guys are looking at this I am going to go back over the bread board with the schematic one more time and see if I see anything wrong there. Any help you can give me will be greatly appreciated.
Thanks!
Vince
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Follow Ups
- Re: need to see a schematic - Vinnie 03:55:32 12/26/04 (0)
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