Stromberg Carlson ASR-120

[fxer1982]

thanks gadget73...

 

[fxer1982]

the pre amp is also Stromberg Carlson that is where it has the Cathode Follower. my mistake.

 

[fxer1982]

Has anyone tested the frequency response or square wave response of these transformers as they're used in the original amplifier? I have a pair that I removed from an ASR-120 (the power transformer was used in another project), and trying to decide if they're worth repurposing for hi-fi. They look a little small, but performance might be OK if materials and winding techniques are good. Anyone have any data?

Jack

Jack : I have 4 of these ASR 120 amps. Ive been running 15" altec Lansing # 422 8Z , mid horn magnavox, high freq horn zenith never needed to push them hard in volume they are loud and Alnico magnet all of them. Im going through these to sell after words. I found a set of Mono blocks Stromberg Carlson AP-437 40 watts continue, 100 watts instantaneous push pull 6550 1959 Tung -Sol power tubes.

 

[TriodeLuvr]

Jack : I have 4 of these ASR 120 amps. Ive been running 15" altec Lansing # 422 8Z , mid horn magnavox, high freq horn zenith never needed to push them hard in volume they are loud and Alnico magnet all of them. Im going through these to sell after words. I found a set of Mono blocks Stromberg Carlson AP-437 40 watts continue, 100 watts instantaneous push pull 6550 1959 Tung -Sol power tubes.

I used the power transformer from my ASR-120 to build a nice 2xEL34 guitar amplifier. The 7408s that came with it were sold a few years ago. The output transformers are the only thing left. I might repurpose them for a couple small guitar amps down the road. A bare bones design with push-pull 6AQ5 outputs would be inexpensive to build.

Jack

 

[gadget73]

I'd go 6CM6 if you don't already have the tubes. 6V6 in a 9 pin bottle and even cheaper than a 6AQ5.

 

[TriodeLuvr]

I'd go 6CM6 if you don't already have the tubes. 6V6 in a 9 pin bottle and even cheaper than a 6AQ5.

Thanks, good tip. I have a decent number of 6AQ5 on the shelf at the moment. Building a new headphone amplifier with them now.

Jack

 

[ceylon]

ASR -120 output transformers are ultra linear

nope.

 

[ceylon]

I'd go 6CM6 if you don't already have the tubes. 6V6 in a 9 pin bottle and even cheaper than a 6AQ5.

oh. im not familiar with this type. good information as always, @gadget73

 

[gadget73]

never used it, I came across it somewhere while looking for a 9 pin 6K6 but it seemed like a nice thing to build around. When the datasheet directly says its a 6V6 there isn't a lot of interpretation required.

6V6 tubes got re-packaged a lot. I seem to remember there is a compactron that has a 6V6 section in it too.

 

[Tom Bavis]

Don't know of a 9-pin equivalent for 6K6, but 6AR5 is the 7-pin equivalent. EL95/6DL5 is maybe close enough.

6EY6 and 6EZ5 are close to 6V6 - higher heater current and transconductance. The 6LU8 Compactron and 6LR8 novar are essentially 1/2 a 12AT7 plus a 6EZ5.

 

[gadget73]

I was after the 9 pin to see if it would work in something that originally had 6bq5 tubes and some output transformer that wanted a lower than I was going to use speaker impedance. Operating conditions for a 6K6 call for a higher plate to plate load than a 6bq5 so I was thinking perhaps it would work out since it was less of a mismatch. I ended up swapping the transformers on that amp.

I figure some day I'll end up with a suitable 6V6 amp to try that experiment on and use actual 6K6 tubes.

There are a number of vertical output tubes that seem like they should make good audio amp tubes. Considering the vertical output is a ~3 watt single ended amp that needs to have good linearity thats not real surprising.

 

[TriodeLuvr]

Don't know of a 9-pin equivalent for 6K6, but 6AR5 is the 7-pin equivalent. EL95/6DL5 is maybe close enough.

6EY6 and 6EZ5 are close to 6V6 - higher heater current and transconductance. The 6LU8 Compactron and 6LR8 novar are essentially 1/2 a 12AT7 plus a 6EZ5.

I've been looking at 7-pin tubes more seriously recently. I wish there were more small-signal (and high gain) equivalents. Most of the 7-pin types in that category seem to have a reputation for microphonics or noise issues. I guess manufacturers put more effort into the 9-pin tubes that were destined for stereo hi-fi.

Jack