Author Topic: Can anyone please recommend a good output transformer? (Read 8751 times)

Underground_Player · « **on:** March 10, 2006, 06:59:40 PM »

My Seymour Duncan Convertible apparently has shot filter caps, excess solder flux causing shorts, etc etc etc, and... :o ...a leaky output transformer.

Now I don't really know what this means, but I do know I probably need a new one.

After brief research at the websites of Obsolete Electronics, Hammond etc I still have no idea how to go about choosing the right one. I've learnt that bigger is better detail-wise, hi-fi transformers are made of better grades of metal and are therefore more expensive, and that leakage will cause some top-end roll-off, which hopefully explains why my amp has been sounding increasingly dull!

I'm tempted to just get the 'best', highest-grade hi-fi style one I can afford in an effort to get more detail. Are there any downsides to using such a thing in the subjective world of guitar tone? All the old Plexis and suchlike appear to use pretty rubbish transformers, and they sounded ok!
Thanks for any help........and if you guys can recommend any particular type of filter cap then all the better!

HTH AMPS · « **Reply #1 on:** March 10, 2006, 11:57:22 PM »

depends on your amp as to what OT you should get - take it to a reputable tech and see what he advises. if it uses EL34s, then you have many options, I would be carefull about spending silly amounts of money - there are some very nice OTs that can be had without breaking the bank.

If your amp uses 6L6s then you're gonna need an OT with a primary Z matched to those valves.

Is it a 50 or 100w amp? does the output stage run ultra linear?

HJM · « **Reply #2 on:** March 11, 2006, 11:07:45 AM »

I plunged for a mercury magnetics OT but I hope it was worth the ££££! I got a good price though.

Ebay is a good place. Webervst make good price OTs but I've not tried one. People like Dagnel and Danbury often will sell you a single transformer here in the UK.

I think your amp is 6L6 isn't it?

Underground_Player · « **Reply #3 on:** March 11, 2006, 02:19:15 PM »

Thanks for the info :)

Quote

Is it a 50 or 100w amp? does the output stage run ultra linear?

It's 60 watts running two EL34s, or around 15 watts using Yellowjackets and EL84s.
What do you mean by the output stage running 'ultra linear'?

There's a chassis pic @ www.diyguitarist.com/GuitarAmps/Convert60.htm
Obviously it's pretty big as far as OTs go.

Assuming I decide which make to go for, do I have to measure the transformer size, measure the bolt spacings and all that? This amp's not exactly a Marshall or Fender for which I've seen loads of transformers that you can buy off the shelf :(

Ratrod · « **Reply #4 on:** March 11, 2006, 04:45:26 PM »

I have an Amplimo in my Fender. It's supposed to be very good. I'm no expert. Soundwise the amp has improved somewhat.

_tom_ · « **Reply #5 on:** March 11, 2006, 05:49:12 PM »

Quote from: Ratrod

I have an Amplimo in my Fender. It's supposed to be very good. I'm no expert. Soundwise the amp has improved somewhat.

Really? What was the difference in tone? Good enough to get it done to my amp would you say?

Ratrod · « **Reply #6 on:** March 11, 2006, 06:18:33 PM »

Quote from: _tom_

Quote from: Ratrod
I have an Amplimo in my Fender. It's supposed to be very good. I'm no expert. Soundwise the amp has improved somewhat.

Really? What was the difference in tone? Good enough to get it done to my amp would you say?

As long as yours is working fine, I would go through all that trouble. The sound seems to be a bit smoother and the volume knob is better to control. It doesn't go loud as quickly as it used to. I think a set of different tubes would do more for your sound. The stock transformers in Fender amps aren't bad at all. I had to change mine because it short circuited. This only happens to 1 in a 1000.

HTH AMPS · « **Reply #7 on:** March 11, 2006, 07:51:02 PM »

Looking at that page with the schematic and descriptive text it basically looks like a bog standard 50w, EL34 OT with a primary impedance of 3400 ohms should be fine.

You can go your own route or I've got a 50w Drake OT from a JCM800 that you are welcome to, call it £35 plus P&P. Obviously it's been used and the leads are cut to length for a Marshall 2204 so you may need to extend the leads (maybe not either). It's nothing some extra stranded wire and shrinkwrap won't fix.

:twisted:

Underground_Player · « **Reply #8 on:** March 12, 2006, 05:00:32 PM »

Quote

Soundwise the amp has improved somewhat.

Good, I won't be totally wasting my money then!

Quote

Good enough to get it done to my amp would you say?

Tom you have a serious GAS problem :lol:

Quote

I've got a 50w Drake OT from a JCM800 that you are welcome to, call it £35 plus P&P.

Thanks, but I reckon I might as well go for a real upgrade - I've been budgeting for a whole new amp, so spending a little extra on an OT doesn't seem so bad.

HJM I've checked out Mercury Magnetics, and it seems they're one of/the best out there.
However: they're an American company with, as far as I can Google, no UK distributor; secondly, they make transformers for every good amp co. except Seymour Duncan (although they basically say to just get in touch and they can sort you out with anything); and finally, they seem pretty pricey - more of a problem if I'm going to have to ship one over here and pay the carriage etc on what is essentially a big lump of steel.

I just tried ebay with no luck.

So Hayden, where did you purchase yours?

HJM · « **Reply #9 on:** March 12, 2006, 05:24:27 PM »

Metroamp.com

Got a bit of a deal with some other bits! 8)

I'd fit the drake to be honest - it's a great price from HTH and the old drakes from JCM800s are good units.

The Mercury Mag will be about $200 plus around $80 shipping, I doubt it will be worth the outlay next to a good Drake, hey Mercury model the drake as a basis!

Underground_Player · « **Reply #10 on:** March 12, 2006, 05:30:41 PM »

Thanks. In that case, HTH I think you've found a buyer!

Very final last thing probably - are the bolt sizes/holes universal? I mean will the Drake actually fit?!

HTH AMPS · « **Reply #11 on:** March 12, 2006, 07:49:10 PM »

the 'footprint' (mounting holes) are generally fairly standard since the stack is the same size from one OT to the next 99% of the time.

If you should discover that the holes don't line up then it's no great shakes to drill a few more holes but I seriously doubt that will happen.

drop me an email if you want it... media_ian@yahoo.co.uk

:twisted:

5F6-A · « **Reply #12 on:** March 14, 2006, 11:35:15 AM »

My vote goes for Mercury Magnetics!

Underground_Player · « **Reply #13 on:** March 15, 2006, 07:14:35 PM »

^ Well that's just thrown a spanner in the works hasn't it

5F6-A · « **Reply #14 on:** March 16, 2006, 05:34:33 PM »

sorry.... but MMs are superb. I deal with paul and he knows his stuff