Crate amp died, transformer issue anyone know of can get replacement

Flattop

Crate gxt 100 power transformer fried
It's got valves in preamp so needs 38-0-38 rectified and 350v ht feed
Made by slme 
Anyone know if can get replacement anywhere or is it done
Thanks in adavance

ICBM

Even if the original is unavailable (likely), it should be possible to substitute something similar, eg a Marshall Valvestate AVT100 transformer - I think I've got a couple of those, if I can find them I can check the spec if you want. Whether it physically fits is possibly the bigger issue - there's a limit to how much work is worth doing on something like this if you have to pay someone to do it. Obviously less of a problem if you can do it yourself.

Flattop

Thanks for reply
I've looked at schematic and if it didn't have high voltage I think a transformer would be easy to find but the 350V might be the stumbling block
Yes please check the spec on the Avt 
I can do it myself if it works, I do like the amp, pretty decent sound for hybrid

ICBM

Will do, I’ll have a look and let you know tomorrow. I’m pretty sure I’ll have at least one, I’ve scrapped a couple of AVT100s. (Not for transformer failure.)

A worst-case option would be to use a normal 100W solid-state amp transformer for the main supply and a separate small one for the valves, like a little valve radio one - but better to do it all with one if it’s possible.

ecc83

Or, you might be able to find a low voltage DC-DC converter like the one in B's HT pedals. That runs 300V at about 3mA, how many pre amp valves are there?

You also have filament volts to consider, are they DC off the 38 V rail? https://vvttransformers.co.uk/ht_tx.htm

Those folks do a few HT + heater transformers with a 20mA HT secondary. I reckon you want around 250V into a bride to get 350V HT

Dave.

Flanging_Fred

When I needed a replacement power transformer for an old Groove Tubes amp, I found that Tube Amp Doctor in Germany could make me one to spec which was a fraction of the price of an original Mercury Magnetics one. 

It might be worth checking their website to see if they can make one. I was really pleased with their service.

Flattop

Thanks for replies guys
Amp has 2 ecc83's which heaters run off 38v rail
I'm hoping to get 1 transformer which can save the amp
So I've calculated 27-0-27  with 0-250 in order to get correct voltage when rectified
If can't be obtained the 2 transformers may be a solution, a mate has gave me an old HH transformer but it's a bit high 38-0-38 unrectified so would be 47-0-47 bridged

ICBM

My mistake, sorry - the AVT uses a voltage doubler to drive the valve HT from the main supply and runs it at less than 160V.

The one you want is a VS100R transformer - that has a separate HT winding. Typically for Marshall, no voltages are given on the schematic, but going by the cap ratings the LT must be under 50V and the HT at least 250V.

Of course, I don't have a transformer as VS100s are less prone to terminal catastrophic failure and are worth fixing...

Flattop

OK thanks anyway for trying
Need me thinking cap on now

ecc83

Flattop said:

OK thanks anyway for trying
Need me thinking cap on now

PM me, had an idea

Dave.

Modulus_Amps

If you know the voltages and currents I can get one made for you. PM me if you need to.

clarkefan

Gotta love this place

normula1

Don't know if it's viable from a fost perspective, but can get transformers rewound https://industrialrewindsltd.co.uk/

Flattop

Thanks all for replies, making progress, grateful to everyone