Changing The Transformer Of My Mesa 2:90

Yakult

Ok, getting my Mesa 2:90 power amp tomoro! But its 110v. So I wanna change the tranny to 220v.

How much will it cost to do this profesionally?

Karl Hungus

I have no idea. Would you not consider just getting a power transformer from Maplins?

Voodu Child

A general instruments forum is the wrong place to ask that question tbh.

Better to actually get in contact with an amp tech. The grailtone boogie forums will also be a more useful source of information.

Here is a copy of part of the 2:90 board, which you may find useful depending on your technical knowledge. You can see the main difference between 117 and 230/240 is the input primary.



I don't have a higher quality copy of this.

Yakult

I can see the difference alright, but dont have a clue what it means! haha!

Voodu Child

The simple answer is get a hold of a good amp tech.

Tbh, most of my amps are US voltage, and if it was cost effective to convert them to 220-240, i'd have done it. But i havent.

You'll know when you get a quote whether you think it's worth it to you or not. Some of the transformers have mulitple taps at different positions in the primary coil meaning a conversion can be done by moving a few links. Other times you'll need a whole new transformer, which will be hugely expensive.

Bear in mind good amp techs can charge e50 and hour. A e100 external stepdown makes a lot of sense compared to the cost youre going to be looking at for the conversion.

Yakult

yeah I kow what you mean! hopefully it will have multiple taps so he wont charge too much!

But if its a case of needing a new tranny I will get a stepdown!

Quattroste

It was Maplins for me too on my Mesa. I don't like amp surgery

Eoin Madsen

The only difference should be the transformer primary. But the schematic there indicates that the primary does not have multiple taps (gone are those glory days). So I guess they use a different transformer in US and EU models to make exactly what you're trying to do difficult.

I don't think you'll find a tech with a suitable replacement to hand in this country, unless by some lucky fluke. You could search ebay for a replacement (a bit too specific tbh, I doubt you'll get lucky) or you could try and get one made.

www.antrimtransformers.com or someone would probably do a torroidal transformer to match. You could send them the schematic and ask for a quote for a once off PT. I've dealt with them in the past and found them reasonably helpful. You'd want to know the dimensions of what it's replacing too though. I'd guess it would be a couple of hundred euros, minimum. Any number of random valve amp PTs might match and fit either. Again, ebay perhaps, or try for a new Mercury Magnetics or Heyboer or something. Possibly an amp tech would be able to source this for you, but I wouldn't hold my breath in this country tbh.

Changing the transformer itself is easy enough but I wouldn't walk you through it for fear that you'd try it and accidently electrocute yourself. Really, you'd still need to hire a tech to fit it even if you got one.

Tbh, the maplin transformer is a much better idea. Heafty amp though, I'd worry just a little that the Maplin wouldn't have enough wattage for the power consumption. They only go up to 300 VA.

SirLemonhead

I'd sell it tbh, sounds like a whole lot of hassle

It's no mesa boogie, but this is nice and cheap I guess?

http://cgi.ebay.co.uk/Peavey-Classic-60-all-tube-power-amp-Classic-Series-6L6_W0QQitemZ190144501356QQihZ009QQcategoryZ10171QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Eoin Madsen

Nah, as long as 300VA is enough, the Maplin transformer is pretty straight forward, and they're only €34 if you get them on the right month (€65 on the off-month).

I have one for my US-bought DBX outboard. It's grand.

Voodu Child

300Va wouldnt be enough for a 2:90, but anyway, RHCP got a transformer with the amp so this thread might as well end.

And yeah, there's zero hassle with using an external transformer. One extra box, that's it. I'd prefer one extra (small) box to lug around than to pay double for some products.

As for swapping the internal transformer, bear in mind that the transformer plays a HUGE role in the character and tone of the amp. This is something a ot of people don't know or overlook. So you can swap in a transformer that's technically correct, and end up with a different sounding beast. Witness the whole pre/post 500 Rectifiers etc.

Yakult

^the transformer I got is a internal when isnt inside so its dangerous.. So Im gonna get a 5kw external from Maplins!

Voodu Child

R_H_C_P wrote:

^the transformer I got is a internal when isnt inside so its dangerous..

I don't know what the above means tbh, did you not get a proper step-down transformer

But anyway, if you didn't get the right one, you'll need a 760watt minimum transformer (ie 800watt).

I'd go for 1000watt to be on the safe side.

Eoin Madsen

voodoo_child wrote:

As for swapping the internal transformer, bear in mind that the transformer plays a HUGE role in the character and tone of the amp. This is something a ot of people don't know or overlook. So you can swap in a transformer that's technically correct, and end up with a different sounding beast.

You're thinking of the output transformer. The power transformer will have some effect on the sound, but it's minimal by comparison. One good PT works as well as another. And I seriously doubt that the stock Mesa power transformer is anything special.

R_H_C_P wrote:

So Im gonna get a 5kw external from Maplins!

I'm not aware that Maplin do anything over their 300VA step down.

Yakult

thats true I checked it after the post!

Eoin Madsen

You might pick up a 1000 watt step down somewhere on Ebay. You'll get screwed on shipping though.