Thanks: Trying to do this with minimum investment.......

Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

Posted by grhughes on September 20, 2010 at 03:00:42

In Reply to: Just saw this posted by Slick on September 19, 2010 at 19:54:54:

with the tubes and transformers I have on hand. Got a considerable junkbox. Lundahl makes great stuff but a little too rich for my blood. These RCA transformers I have just learned were made for plate loads of a triode strapped 6F7 pentode or a 1621 which was a noise sorted 6F7. I finally found the original schematic of the mixer so the primary impedance is on the order of > 15K which is way too high I believe to drive passively without considerable insertion loss from this beta follower circuit. I ran a frequency response check on the transformers and they are very nice as well as distortion measurements; pretty stellar! I have no way of measuring inductance. I have some other Scully transformers that are much lower primary impedance around 1K. Do you know the output impedance of the beta follower? I understand the u follower would offer also a lower output impedance, in which case I may not need an output transformer at all. My line from the preamp to power amp is about 20 feet.Ray

This post is made possible by the generous support of people like you and our sponsors:

Follow Ups Full Thread

Topic - Anyone built the Beta follower VALVE AMPLIFIERS, Page 126,Fig.2.44? - grhughes 09:30:40 09/15/10 (12)

RE: Anyone built the Beta follower VALVE AMPLIFIERS, Page 126,Fig.2.44? - Slick 20:24:15 09/15/10 (11)

High Beta = BC559C - Mark Kelly 22:26:32 09/17/10 (1)

Thanks Mark! Always good to hear from the wine maker down under! - grhughes 10:39:54 09/18/10 (0)

Thanks! What Cree Schottky diodes are you using? - grhughes 08:22:39 09/16/10 (8)

RE: Thanks! What Cree Schottky diodes are you using? - Slick 12:42:37 09/16/10 (7)

Thanks, Stuart! - grhughes 13:46:16 09/16/10 (6)

RE: Thanks, Stuart! - Slick 06:59:18 09/17/10 (5)

If I could buy the ideal transformer to use as a plate load what should I look for inductance wise? - grhughes 07:42:35 09/17/10 (2)

Just saw this - Slick 19:54:54 09/19/10 (1)

Thanks: Trying to do this with minimum investment....... - grhughes 09/20/1003:00:42 09/20/10 (0)

My worry is that the transformer can't stand much current in the primary winding.... - grhughes 07:35:38 09/17/10 (1)

By all means... - Slick 08:44:55 09/17/10 (0)

Follow Ups

Thanks: Trying to do this with minimum investment....... - grhughes 09/20/1003:00:42 09/20/10 (0)

Post a Message!