RE: I realize specs aren't everything...

Posted by Eli Duttman (A) on March 25, 2015 at 14:14:27

In Reply to: RE: I realize specs aren't everything... posted by Steve O on March 25, 2015 at 13:34:27:

The Grande idea has been out and about for quite some time. Putting together something "official" has not been done.

Compared with the "12" W. tube "El Cheapo", the "taller" B+ rail needed by the 7591 allows the 'T7 plate load to increase to approx. 80 Kohms. 33 K carbon film and 50 K inductive wirewound parts in series could be fine.

Combination biased "finals" would be employed. "Stand" the tied together cathodes of the O/P tube pair on a 470 muF./100 ohm bias network. A single "idle" current set trim pot. is fine and the 100 ohm resistor is a very convenient test point. By making part of the total bias voltage self generated, protection against runaway, which the current production EH 7591 is known to occasionally do, is provided and 330 Kohm grid to ground resistors will be safe. Keeping the 7591 grid to ground resistor value up prevents splitter/driver gain from becoming insufficient.

For monoblocks, AnTek AS-1T300 power trafos should be quite adequate for B+ and heater power.

Give me some time and I'll concoct a scheme for the requisite negative voltages.

Eli D.

AnTek AS-1T300 (Open in New Window)

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Follow Ups Full Thread

Topic - Eico HF-14 build from scratch - banpuku 06:11:13 03/25/15 (24)

Less RISK ...... - drlowmu 13:25:41 03/25/15 (0)

If it were me, I would be looking at a PP EL84M or 6L6/KT66 design using SS soft recovery rectifiers - Timbo in Oz 13:04:13 03/25/15 (1)

RE: If it were me, I would be looking at a PP EL84M or 6L6/KT66 design using SS soft recovery rectifiers - Eli Duttman 14:46:34 03/25/15 (0)

RE: Eico HF-14 build from scratch - DAK 11:25:33 03/25/15 (0)

Is that really enough power? - Triode_Kingdom 11:25:11 03/25/15 (2)

RE: Is that really enough power? - banpuku 12:19:42 03/25/15 (1)

Keep in mind that the HF14 doesn't really do 14W... - Steve O 12:48:48 03/25/15 (0)

I realize specs aren't everything... - Steve O 08:57:01 03/25/15 (10)

RE: I realize specs aren't everything... - Eli Duttman 11:01:51 03/25/15 (9)

RE: I realize specs aren't everything... - Steve O 12:44:01 03/25/15 (8)

RE: I realize specs aren't everything... - Eli Duttman 13:19:22 03/25/15 (7)

Schematic for El Cheapo Grande? - Salectric 13:56:40 03/25/15 (1)

RE: Schematic for El Cheapo Grande? - Eli Duttman 14:26:39 03/25/15 (0)

RE: I realize specs aren't everything... - Steve O 13:34:27 03/25/15 (3)

RE: I realize specs aren't everything... - Eli Duttman 14:14:27 03/25/15 (2)

Negative Rails - Eli Duttman 17:44:18 03/25/15 (1)

RE: Negative Rails - Triode_Kingdom 16:52:25 03/27/15 (0)

RE: I realize specs aren't everything... - sony6060 13:30:03 03/25/15 (0)

RE: Consider Tublab's Simple P-P - sideliner 08:07:05 03/25/15 (0)

RE: Eico HF-14 build from scratch - sony6060 07:21:01 03/25/15 (4)

RE: Eico HF-14 build from scratch - banpuku 12:23:15 03/25/15 (2)

RE: Eico HF-14 build from scratch - sony6060 13:24:46 03/25/15 (0)

If you go with a 5AR4 in place of a 6CA4... - Steve O 12:54:46 03/25/15 (0)

RE: Eico HF-14 build from scratch - banpuku 07:30:53 03/25/15 (0)

Follow Ups

RE: I realize specs aren't everything... - Eli Duttman 14:14:27 03/25/15 (2)

Negative Rails - Eli Duttman 17:44:18 03/25/15 (1)

RE: Negative Rails - Triode_Kingdom 16:52:25 03/27/15 (0)

RE: I realize specs aren't everything...

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