Need help identifying the manufacturer of this output transformer

S

Sam Lysinger

Please support your local mad scientist
Subscriber
Greetings,

I've had a pair of these for several years and I am curious to know who wound them as I have never found a matching transformer can since. They weigh around 21lbs each and (if I did my math correctly and got my colors right) have an output impedance of 2200 ohms.

They say West 0-200 on them

I can only guess they were intended for push pull parallel KT88s (or 3 sets of 6l6 in parallel) and can handle 200W based on the number and the weight, but that is a total guess.

I've a pair of identically sized (and completely unlabeled) blue crinkle painted transformers from the same sale with cloth wrapped wires as opposed to the plastic seen here.

Pics are attached, all insights are greatly appreciated!
 

Attachments

  • IMG_9425.JPG
    IMG_9425.JPG
    147.7 KB · Views: 81
  • IMG_9426.JPG
    IMG_9426.JPG
    115.9 KB · Views: 82
  • IMG_9427.JPG
    IMG_9427.JPG
    109.4 KB · Views: 81
Register to hide this ad
Dynaco A-451 was about that size, 2200 Ohms UL, rated 120 watts 20-120 KHz, 240W 30-15 KHz. Could be Dyna or a clone. Cloth vs. PVC wire could be same maker, different lot or two vendors for same part. Or the blue ones could have been repainted for a project that was never finished...
 
That is a West Fillmore output transformer. West did, in fact, use Dynaco A-451 output transformers, and the secondaries are the standard 4-8-16Ω. I played through a Fillmore for a while, and let me tell ya, my ears are STILL ringing. What a tone, but only when cranked. :confused:
 
Thanks everyone for taking the time to look at this mystery transformer and identifying it! I measured the physical dimensions of the transformer and it is dead on size wise to the A451. This was an unexpected surprise. I checked the colors of the wires on the blue crinkle paint pair and they match the A441 (and those have never been installed judging by the lead lengths and the leads themselves). I will put voltage on one of those in the next few days and measure its turn ratios to be sure. Thanks again!
 
Sam Lysinger said:
Thanks everyone for taking the time to look at this mystery transformer and identifying it! I measured the physical dimensions of the transformer and it is dead on size wise to the A451. This was an unexpected surprise. I checked the colors of the wires on the blue crinkle paint pair and they match the A441 (and those have never been installed judging by the lead lengths and the leads themselves). I will put voltage on one of those in the next few days and measure its turn ratios to be sure. Thanks again!
Click to expand...

You are fortunate to own two pairs of these!
 
In the guitar amp world, anything goes -- with emphasis on the word "anything". I certainly know that. But still, intentionally reducing the reflected load to the output tubes down to half the nominal (er, traditional?) rating -- and then operating them that way at (basically) a sustained -- full -- power output level and more (as an amp like this would likely have been used at), had to be absolute murder on the output tubes. But, it was a time before sound support systems existed, and amp makers would do anything to try and get the power they needed to fill large venues, especially with bass amps. The question was -- what would take out the tubes first, a transient tube arc? Or the cathodes being stripped clean of their last emit-able electrons? Ultimately, nobody cared. The tubes were going to need regular replacing one way or the other anyway, so it didn't matter. In the guitar amp world, anything goes -- and especially during the particular time the West was manufactured. Rock On!

Dave
 
I'll add to what Dave said that if not for guitar amplifiers which ritualistically sacrifice their tubes, we hifi guys would probably be paying more for narrower variety than we are now.

I dont mess with guitar or musical instrument amps but I see their importance in that the people who love and maintain them are keeping the supply chains rolling in addition to hifi folks...
 
arts said:
That is a West Fillmore output transformer. West did, in fact, use Dynaco A-451 output transformers, and the secondaries are the standard 4-8-16Ω. I played through a Fillmore for a while, and let me tell ya, my ears are STILL ringing. What a tone, but only when cranked. :confused:
Click to expand...

Built for Grand Funk RR stadium tours. Correct? :)

 
120W_KT88ppp_with_a451.jpg

There's the obvious starting point for a circuit for those! Basically, a double-power Mk III...

Regards,
Gordon.
 
dcgillespie said:
In the guitar amp world, anything goes -- with emphasis on the word "anything". I certainly know that. But still, intentionally reducing the reflected load to the output tubes down to half the nominal (er, traditional?) rating -- and then operating them that way at (basically) a sustained -- full -- power output level and more (as an amp like this would likely have been used at), had to be absolute murder on the output tubes. But, it was a time before sound support systems existed, and amp makers would do anything to try and get the power they needed to fill large venues, especially with bass amps. The question was -- what would take out the tubes first, a transient tube arc? Or the cathodes being stripped clean of their last emit-able electrons? Ultimately, nobody cared. The tubes were going to need regular replacing one way or the other anyway, so it didn't matter. In the guitar amp world, anything goes -- and especially during the particular time the West was manufactured. Rock On!

Dave
Click to expand...

My friends at Acorn Amps always look at me funny when I refer to guitar amp designers as destroyers ^_^. They abuse tubes on purpose to get a desired effect and I have no problem with that as the end user knows what they are getting into.
 
You must log in or register to reply here.
Back
Top Bottom