Transformer Replacement

[Ekkel]

Hi people,

it's been suggested to me by another member of this forum that replacing the transformer in my amp can improve the tone significantly (the amp is a Marshall DSL 50w). Before I go ahead and buy a new transformer I wonder if anyone can help me with tips and suggestions. Must admit I don't know much on the subject. I will have someone professional do the change, but I have to buy it myself. Can anyone recommend a brand? I been in contact with a Hi-fi dealer, but I am a bit unsure if the guy there would know what would work in a guitar-amp. I suppose there could be a danger here that if I bought something that didn't work with the amp, I could destroy it? Anyone else here with good results doing this?

Thanks for any input!

 

[Kent S.]

Re: Transformer Replacement

Any transformer of the same design, ratings, and specs will work ... so yes there are going to be direct replacements in 90% of the cases, anything else would be custom made. My advice, hit Hammond's website as they have a good deal of info. Call and speak with someone, if nothing else give them the manufacturer and model of the transformer in the amp (don't know it, contact the amp company and ask), let the guys and girls at the transformer company select a suitable replacement. At the minimum you need to know what comes off of it, (does the filament supply come off it, or does it have a separate supply?, Does the bias come off of it, or does it have a bias supply tranny as well?), what's the total current rating of the primary and secondary, can you find say an alternate transformer that will work if wired differently? An amp repair friend of mine had to find a replacement for an old vintage amp ( I think it was a Gretsch amp? ), tranny no longer made, had to go with a center tapped tranny, had to redo part of the power supply, and run the filament supply to two separate smaller trannys in order to keep from overloading the current rating of the first ... real messy, and very time consuming and costly. Of course that's input, output trannies, well unless someone is offering a direct replacement for the one in that amp ... well see the problem ... there are others that may work fine, but are they going to sound any better ... too subjective. If you just want a heavier duty tranny for it, then fine, but trying to do tonally changes with a transformer ... Much easier things to do in life. Ask the forum person that suggested it how there's worked out, and go thru who they did. Other wise start calling transformer manufacturers, and get some model and specs on yours from the amp maker.
Best place to start.

 

[Thames]

Re: Transformer Replacement

Ekkel,

Contact Mercury Magnetics, they have awesome output transformers, not cheap, but awesome, probably the best made. You should also check out Obsolete Electronics (OEI) and ask them. Both are knowledgeable sources. Check out the forums at Ampage.org, another great source of tech help.

You could also ask Trace at VoodooAmps for suggested mods on the DSL50 and ask him if the OT worth being replaced.

Changing an OT is rather simple, but also dangerous, as you're working INSIDE an amp containing LETHAL voltages... Usually, you have a minimum of 5 wires to connect (up to 9).

 

[That90'sGuy]

Re: Transformer Replacement

Ekkel,

Contact Mercury Magnetics, they have awesome output transformers, not cheap, but awesome, probably the best made. You should also check out Obsolete Electronics (OEI) and ask them. Both are knowledgeable sources. Check out the forums at Ampage.org, another great source of tech help.

You could also ask Trace at VoodooAmps for suggested mods on the DSL50 and ask him if the OT worth being replaced.

Changing an OT is rather simple, but also dangerous, as you're working INSIDE an amp containing LETHAL voltages... Usually, you have a minimum of 5 wires to connect (up to 9).

+1

Mercury magnetics are known for their transformers!

Here's a bit of info on transformers (in case anyone was wondering). I believe I have most of this correct, if not, please let me know.

I just worked with transformers today They really aren't difficult at all. With transformers, you're taking a voltage from an AC source and converting it to another voltage. There are step-down transformers and step-up transformers. All guitar amps use step-down transformers (I believe). It's taking, for instance, the 120v in my house, feeds it into the high voltage taps (denoted by H on the transformer) and lowering it to another voltage (taps for the lower voltage are denoted by X) which, as a result, increases the current. What voltage you end up with depends on the ratio of primary to secondary coil turns.

How does it work? It works of off an AC source [that means that electricity flows back and forth in a circuit - it constantly moves] which helps to create electromagnetic induction. Electricity flows through the primary coil (just a conductor wound in circles) [which creates a magnetic field] and transfers to a secondary coil and out to the rest of the circuit. Quality does make a difference when it comes to results. The best conductor is silver, but to save costs, most places will use copper. What helps strengthen the magnetic field is a permanent magnet in between the primary and secondary fields (iron is a very good one). This allows more electricity to be generated. Motors are made in this regard. In order to get a generator, a motor twists another motor to create energy (from the first motor's torque or "twisting action"). A generator is simply a motor that is being moved and that torque creates current itself - that's a while 'nuther story. Transformers simply adjust the current and voltage to whatever they feel fits their amplifier properly.

 

[Curly]

Re: Transformer Replacement

Mercury Magnetics have a great product, however I see a lot of discussion about Marshall trannies over on the 18 watt forum , so I'd suggest asking over there as well

 

[STRATDELUXER97]

Re: Transformer Replacement

I put an O.E.I in my old Marshall 50 watter when they first came out and it made alot of difference overall in the tone of my head...I've done a ton of other cool stuff to my Marshall,but the O.E.I was icing on the cake...

John

 

[Thames]

Re: Transformer Replacement

I put an O.E.I in my old Marshall 50 watter when they first came out and it made alot of difference overall in the tone of my head...I've done a ton of other cool stuff to my Marshall,but the O.E.I was icing on the cake...

John

Hey John, tell me more about that amp, is it a JMP or a good ol Plexi ?

Just wondering if swapping for an OEI is worth only when the amp is pushed really hard...

 

[MrHeavyMetal]

Re: Transformer Replacement

+1. I've read a lot of good things about the Mercury transformers too.

http://www.mercurymagnetics.com

 

[STRATDELUXER97]

Re: Transformer Replacement

Hey John, tell me more about that amp, is it a JMP or a good ol Plexi ?

Just wondering if swapping for an OEI is worth only when the amp is pushed really hard...

Mine is a Non-master 1987 built in 73 with the metal panel that was all done up to the "Plexi" changes....The O.E.I. was a great after thought that actually made my amp sound alot better...

The Mercury Magnetic stuff is supposed to be great also,but Trace Allen(Voodoo Amps) recommended the O.E.I at the time...

 

[the guy who invented fire]

Re: Transformer Replacement

Mine is a Non-master 1987 built in 73 with the metal panel that was all done up to the "Plexi" changes....The O.E.I. was a great after thought that actually made my amp sound alot better...

The Mercury Magnetic stuff is supposed to be great also,but Trace Allen(Voodoo Amps) recommended the O.E.I at the time...

if yours in a 73 then it should have 4 imputs, no master volume and it's on a PC board right? How do you like it? I think that is gonna be the next amp I buy (a 4 hole non MV 50 watt Marshall head)

 

[STRATDELUXER97]

Re: Transformer Replacement

if yours in a 73 then it should have 4 imputs, no master volume and it's on a PC board right? How do you like it? I think that is gonna be the next amp I buy (a 4 hole non MV 50 watt Marshall head)

Right....4 input,no master volume,and basically has the identical PCB as the JCM 800 series....73 was a split year for Marshall in that some were point to point and some were PCB...I wish mine were point to point just for ease of working on it,but it still sounds heavenly regardless...It is a pain getting under the pcb,but I manage and it isn't something I have to do often now that the amp is all setup nice...I Love Marshalls and this one has great tone!

John

 

[the guy who invented fire]

Re: Transformer Replacement

Right....4 input,no master volume,and basically has the identical PCB as the JCM 800 series....73 was a split year for Marshall in that some were point to point and some were PCB...I wish mine were point to point just for ease of working on it,but it still sounds heavenly regardless...It is a pain getting under the pcb,but I manage and it isn't something I have to do often now that the amp is all setup nice...I Love Marshalls and this one has great tone!

That's gonna be my next amp...for me that Marshall head, my twin and tweed Deluxe is all I will need...for a while!

 

[Cazmarzak]

Re: Transformer Replacement

I beleive I was the one who suggested it to him after doing it to my DSL50 head.

It was my First amp in a while after being out of the scene and not plying for a while. WelI obvioulsy knw to replace the stock tubes and when I took it to my amp tech, he suggested it to me.

He said that the newer Marshalls werrre begining to have cheaper parts in them to try and cut costs.

He also told me that with the transformer that it came with, it was Possible that if a power tube blew, that the tranny could also go.


So I let him do it and it only cost me about 150.00 for the tranny and the installl.

Whatever transformer he put in there the mounting brackects DIDN'T line up and he had to drill a few more.

This one was also taller than the stock one. After he did it, my amp had more bottom to it and the tone controls just seemed to react more when I turned them, like they had more range or something.

It has been so long that I can't remember what transformer he put in it, but all I can remember is that it had jpm 45 or something VERY similar stamped on it. I don't have it here to check.

If you want I can give you the # of my amp tech and you can call him and ask what and where to get them from. I'm not sure where you are, He's in PA, you can shoot me an IM or an E-mail if you want.

 

[Ekkel]

Re: Transformer Replacement

Hi folks, thanks for all the info!

Cazmarzak: Yup, thats me

I'll send you and e-mail in a second, would be cool to call your tech!

Nice weekend, everyone!

 

[STRATDELUXER97]

Re: Transformer Replacement

"He also told me that with the transformer that it came with, it was Possible that if a power tube blew, that the tranny could also go."

That's what the "HT" fuse in Marshalls was supposed to protect...Aren't they still using the HT fuse at the back of their amps?