• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Fisher 500c Output Transformers

cabsodyinblu

cabsodyinblu

New Member
Hello AK’ers

I’ve been on the hunt for months for an original output transformer for my wonderful 500c but no luck on the auction site. Can anybody recommend where I could find a replacement or a rewinding/rebuild service? I’ve tried to reach out to Transcendar but he replied back that he’s retired now.

Any leads would be greatly appreciated :-)
 
Register to hide this ad
Don't limit your search to just the 500c. The 800c used the exact same transformers (500c is an 800c without the AM Band (or vice versa)). Otherwise Heyboer transformers can probably build you one. They are in Michigan.

The suffix # (-1 or -2) denotes which channel. Wiring lengths are different (slightly) between them. Try to get the matching suffix transformer. If you have it rebuilt or a new one built, ask them to leave the leads from the transformer @ 12" from the hole in the end bell. Adjust length as needed for neat install.
 
Thank you for pointing me in the direction of the 800c OT and Heyboer. I gave them a ring earlier this morning, hoping to hear from them by tomorrow to see if they’ll be able to build a transformer for me.

in the event that they’re not able to build one for me, I’ve heard a few things about Hammond OTs… Is there a plan C?
 
Hello all,

New member and longtime lurker here … I’m new to tube gear and I’ve been searching high and low for a pair of output transformers that will match the receiver that I have: Fisher 500c. I’ve kept alerts on the auction site for original OTs but it’s been a few months and no luck … Transcendar is out of the game too. They’ve retired. Does anybody have any experience with Hammond OTs or any other company that makes reproduction OTs? It’s looking like my only option is to buy a parts unit to source this part.

Cheers
 
Too bad about Transcendar leaving the game. I had good success with their Fisher and Scott replacements and rewinds. Seems we have fewer and fewer choices sometimes.
 
I’m very sad about Transcendar closing up shop. They were great value for really good transformers. Like they said Hayboer might be able to make you some new ones that are as good as the originals. Jack at Electra print might be able to help as well. Waiting for one to show up could take years and you don’t know what shape it’s in.
 
You need an authentic Fisher output transformer or an exact duplicate for your receiver to work according to original spec. The problem with other off the shelf output transformers is they will have different low and high frequency characteristics and just plopping in something else with the same form factor will change the behavior of the amplifier. You probably could make it work but you would need to tweak the amplifier’s tuning circuits to match or behave well with the new transformer. But that will make that channel behave differently than the other channel with the original transformer. So this is not a good idea.

The only options I’d consider is an actual Fisher output transformer or an exact copy. Exact copy means the same wire diameter used to wind it as well as exactly duplicating the interleave winding method and secondary taps. I bet Heyboer could wind one for you but my guess is not for cheap and they may need some lead time to tear down your broken one to rewind it. I expect they would use the existing iron core of the broken one and just rewind it.
 
Last edited:
@cabsodyinblu

cabsodyinblu said:
.I’ve been on the hunt for months for an original output transformer for my wonderful 500c .Can anybody recommend where I could find a replacement or a rewinding/rebuild service? I’ve tried to reach out to Transcendar but he replied back that he’s retired now.
Click to expand...

Did you hear back from Heyboer as others have suggested? if so what did they say? if not be patient they might just be busy.

cabsodyinblu said:
... I’ve been searching high and low for a pair of output transformers that will match the Fisher 500c. … Transcendar is out of the game too. Does anybody have any experience with Hammond OTs or any other company that makes reproduction OTs?
Click to expand...

Reproduction OT's you might check out Edcor
 
Dswankey said:
@cabsodyinblu



Did you hear back from Heyboer as others have suggested? if so what did they say? if not be patient they might just be busy.



Reproduction OT's you might check out Edcor
Click to expand...


Hope I’m using this quote function correctly. I got in touch with heyboer around the middle of the week, I hope to hear back from them soon as they sounded confident that they may be able to replicate the transformer.

if I went repro, what are the specs that I would be looking? Again apologies, I’m new to tube gear.
 
cabsodyinblu said:
if I went repro, what are the specs that I would be looking? Again apologies, I’m new to tube gear.
Click to expand...

I'll leave that to the more knowledgeable here, fwiw you have some of AK's finest tube minds involved in this thread so one of them should be able to provide that info.
 
Hifi Dave said:
Do you have the part number? I have a Fisher x101D output with about 10hrs on it. It used 7591s.
Click to expand...

cabsodyinblu said:
just sent you a pm. The part number should be T991-116-1
Click to expand...

I would also say you possibly could be treading in bad waters as @Hifi Dave posts sounds like an advert to sell and your response sounds like you wanna take him up on the offer.

A quick review of the rules should clarify what I'm talking about.

https://www.audiokarma.org/forums/index.php?threads/audiokarma-rules.301366/

If I'm wrong my apologies to both parties
 
Ouch, I was just trying to help find a transformer amplication that would fit the bill. Like cars,many parts crossover to other models,makes and years within a given group ....GM, Ford for example.
If I violated a policy or rule I apologize.

Thanks
Dave

P.S. The part number on mine is T849-116-2A.....not the same part.

Again, my apologies if required.
 
googled " Fisher 500c Output Transformers" n there are several videos on how to repair them. many Fisher ot's being sold on the bay. no 500 or 800, but there r several x-101d.
 
But -- they are in fact the same part -- same electrically anyway. Fisher often had different part numbers for the two output transformers used in most of their stereo units -- I mean one part number for the left channel, and a different one for the right. This was done because the transformers had their leads pre-cut to the necessary length by the transformer manufacturer, allowing production time at the Fisher factory to be maximized. In a stereo setting, the two output transformers rarely require the same lead lengths between the two transformers, so the transformers had their leads pre-cut, pre-stripped, and pre-tinned to the position they resided in, which then required separate part numbers. The X-101D used the same exact transformer as the 500C/800C, but had it's own requirements for lead lengths, and so had its own separate part number. In keeping with this approach, the part numbers for the two output transformers specified the X-101D are in fact different, but they are still the same transformer electrically.

Dave
 
If you're really up for some amplifier deep-dive redesign work you could certainly fit some non-original transformer but its going to need tinkering with the feedback and stability stuff to make it perform right. If all of that sounds like I'm speaking a foreign language, then you want an original. Its the only thing guaranteed to drop in with no fuss or bother.
 
dcgillespie said:
But -- they are in fact the same part -- same electrically anyway. Fisher often had different part numbers for the two output transformers used in most of their stereo units -- I mean one part number for the left channel, and a different one for the right. This was done because the transformers had their leads pre-cut to the necessary length by the transformer manufacturer, allowing production time at the Fisher factory to be maximized. In a stereo setting, the two output transformers rarely require the same lead lengths between the two transformers, so the transformers had their leads pre-cut, pre-stripped, and pre-tinned to the position they resided in, which then required separate part numbers. The X-101D used the same exact transformer as the 500C/800C, but had it's own requirements for lead lengths, and so had its own separate part number. In keeping with this approach, the part numbers for the two output transformers specified the X-101D are in fact different, but they are still the same transformer electrically.

Dave
Click to expand...


Dave,
Would it be accurate to say that except for the mounting configuration that all Fisher output transformers utilizing 7591s are interchangeable?
Thanks in advance
 
You must log in or register to reply here.
Back
Top Bottom