Transformer with no label – how to find a replacment?

Hi, it would be hard to get proper help without any specifics such as the make and the model name/number of that guitar amp. and perhaps some closeup pictures of the amp. as well as the transformer

PS: Just in case you’re not familiar with posting pictures on this site you either head over to the official Mr. Carlson’s ”How to”  by following this link:

Uploading Pictures to this Forum

or head over to picturepile.com, open a free account and use that site instead of IMGUR. Just keep in mind that there is more than one way to post pictures here as in: by only posting a link that once clicked will redirect you to the site that contains the pictures or by posting a direct link  which means that your pictures will already be shown on your post. So, there won’t be any link that needs to be clicked (in order) to see the picture. Some how to instructions written by the member ”John Barron” are found here: There is a better way to post pictures so that they show up …  

Alternatively there are other image hosting (free) services that would work the same way  such as https://postimages.org/

This is the one that I’ve also successfully used (a few times) as well.  Good luck. 👍 

@ovi4 

The amp is a PRS MT15 amplifier.  I’ve added some photos of the transformer and the sticker that is on the top  – which does show some numbers but nothing I’ve been able to google to find any info.

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@bh2024el That transformer should have had a proper specs label. Here are some pictures taken from other identical (PRS MT15) amps:

@ovi4 Thanks for the reply!

Are those images by chance from those doing the 50 watt mod on that amp?

Even so I suppose that would work!  Doesn’t hurt to have an oversized transformer!

@bh2024el As far as I know these are original (factory transformers) with no MODs of any kind applied to the amps.

PS: if you open those metal (caps) shields and have a look at the wires you might be lucky and find a broken wire there (however unlikely)  but still… give it a try

@ovi4 I did remove the bolts holding the core plate together, but it appears to be also glued? I suppose I could just pry them apart – I’ve never taking apart a transformer so not sure how much “brute force” to use!  lol

@bh2024el Well. most of the time is well glued so…prepare for some force but…with caution. Perhaps you can try to use a knife with a blade that is dull (not sharp) etc.

@ovi4 I will “do so at your own risk” as Mr. C says!

@bh2024el I too have had a similar problem with a transformer I was trying to source for a power amp I was working on. Where it was not labeled and I could not find specs for the transformer. I eventually did what Mr. C explained in one of his videos removing it from the unit and checking all the leads for continuity for shorts and voltage labeling each wire and color matching.  As a note Mr. C said you don’t have to use an exact replacement just one that works for the application. I had to go the long way doing the MATH to figure out what voltages I needed to make another transformer work. 

In my search I found this when trying to figure out who made the transformer and then was going to contact the manufacture for specs.

• PRS MT-15:

  This is a 15-watt, two-channel tube guitar amp head designed by Mark Tremonti. 

   
• Component Sourcing:

  PRS, like many guitar amplifier manufacturers, often relies on external suppliers for specific components like transformers, rather than producing them themselves. 

   
• Third-Party Suppliers:

  While the specific manufacturer of the power transformer for the MT-15 is not publicly known, it’s likely a company that specializes in producing high-quality power transformers for the guitar amplifier market. 

   
• Mercury Magnetics:

  Mercury Magnetics is a well-known manufacturer of high-quality power transformers, and they are often used in guitar amplifiers. 

   
• Alternative:

  Some users have reported issues with PRS MT-15 output transformers, with PRS stating they are on order from China and not available to supply.

   

@john-barron 

Thanks for the reply. I also reviewed that video again and, in fact, did just that—labeling all the wires on the secondary and organizing them according to their “matching pair,” if they had one.

I was able to remove the transformer cover, and my hope was to determine if I had a loose wire I could reconnect on the primary side, but as luck would have it, that was not the case. The break must be deeper inside.

None of the wires were shorted to the case either, nor were any of the leads shorted.

I’m still not sure what caused the failure – I will admit I had adjusted the bias slightly higher for the 6l6 tubes (sounded better to me) – but used an DMM to sett it properly and still within the tube specs. But perhaps that was too much current for that transformer to supply?  

Anyway, the electronics adventure continues!

@john-barron On the pictures that I posted at the bottom of each label there is the name of the manufacturer : namely: NRE and I had a quick “Glantz” at their website and yes they sell transformers  for tube amplifiers but I just could not locate the same transformer model number. I’m thinking, maybe PRS has specifically requested those transformers as a special item therefore NRE people will only ever sell them and make them for PRS company not as a spare part that people could buy. However, If you (Bill H.) could do a little digging and find perhaps a telephone number of NRE  from their website and ask them directly over the phone. Who knows, they might actually have them for sale thru another retailer or something. It is worth a try .