Replacement Transformers

[hywelg]

I've had a Ceriatone OTS 50w for about 8 years now and the PT has gone bad. Continually blowing fuses.

Anyway I did some searching here and Google and have emailed both Edcor and inMadOut (Italy, someone mentioned them here a while back) to confirm whether their spec will be OK.

http://www.inmadout.com/download/pdf/TA34M50.pdf

https://www.edcorusa.com/xpwr173

Anyone else I should be contacting, ideally UK or EU but if I have to ship from the US I will, but i bet it'll be expensive. Ruled Mercury out on cost. Do Magnetic Components do one?

If I was to replace the OT at the same time who produces the very best , tonally?

[martin manning]

Does your current PT have an extra winding for the relay supply? Not likely you will find that in off-the-shelf units, so you may have to add a small filament transformer.

[rogb]

I've had a Ceriatone OTS 50w for about 8 years now and the PT has gone bad. Continually blowing fuses.

Anyway I did some searching here and Google and have emailed both Edcor and inMadOut (Italy, someone mentioned them here a while back) to confirm whether their spec will be OK.

http://www.inmadout.com/download/pdf/TA34M50.pdf

https://www.edcorusa.com/xpwr173

Anyone else I should be contacting, ideally UK or EU but if I have to ship from the US I will, but i bet it'll be expensive. Ruled Mercury out on cost. Do Magnetic Components do one?

If I was to replace the OT at the same time who produces the very best , tonally?

I know Marcus on here (norburybrook) had good experiences with InMadOut.

I have Classictone in a few builds and they are very good but expensive to ship from US after all the charges.

I sold my old OTS with Hammonds in and I know the fellow gigged it hard with no problems. Contact Phil at Bluebell Audio.

The 50w in my avatar has Classictone and is still running AFAIK after some extensive gigging (not by me, but by a very good guitarist )

I also just replaced my Tweedle Dee with 35w Hammond iron when upping to 6L6 and it sounds great. The Classictone iron went into a stock 5E3 circuit, which sounds lovely.

Today I have been doing a little work on my AB763 with Mercury iron and that sounds great too.

Get the picture? I would get a Hammond in the right spec and save your money. My Mercury Deluxe no reverb set must have cost £300+ to get in my door!

[rp]

Is this a laydown? Does it need to drop in? No idea what the Ceriatone specs are but didn't Dumbles use Fender iron? Hopefully Ceri cloned it pretty close, elec and mechanical. I would research a Hammond 290 Fender replacement like a BF Bassman or Showman/Twin, check here first:

http://www.tube-town.net/ttstore/

Here's the Hammond dist/retailer in the UK

http://www.bluebellaudio.com/

Also in the UK I think Danbury have many old trannies on file like Heyboer does in the US, from what I read of them they do one-offs, couldn't hurt to ask them.

http://www.danburyelectronics.co.uk/

This guy is interesting, doable w/ chrome browser or just google translate.

http://www.welter-electronic.de/bauteil ... _trans.htm

TAD also has current Fender replacement tranies.

These guys stock Hammond and Imadout, site does english:

http://www.uraltone.com/

[hywelg]

Cheers guys. will check out those options.

Yes it is a laydown type and it does have a filament supply that gets to run the relays. Both those options I posted links to have that.

ClassicTone (Magnetic Components) have a Project transformer which has all the requisite secondary windings but the HT is either 660 ( a bit low?) or 760 (a bit high?) and it has no rectifier tap just two 0-15v taps which I guess would require a different voltage regulator than the one currently fitted. Heater has no CT either I guess I'd just have to install two resistors with a tail to ground?


Will report back when I have had some replies.

[rp]

http://www.hammondmfg.com/guitarLinePWR.htm

is either 660 ( a bit low?) or 760 (a bit high?)

is it tube rectified or ss? I'd just match the orig as close as possible.

[jestaudio]

InMadOut, great company to deal with and great traffos, also Phil ate bluebell, had a number of Hammonds from him as well as chassis

[martin manning]

...and it does have a filament supply that gets to run the relays. Both those options I posted links to have that.

You will need a 6.3V filament winding (not a 5V) for the relays, or you may not have enough voltage for the regulator to function properly.

[norburybrook]

I've used Hammonds which I get from Mouser UK web site. You'll need a small transformer for the relays as well( as per a real Dumble|)
I'm Vat registered so they work out a great price as they come ex VAT to me.


InMadOut wound a transformer to my specs with a secondary winding for the relays on my BLuesmaster build.

I must say, they're very good transformers..... mine had so little hum I though it was broken


MC

[martin manning]

The inMADout PT linked above has a second 6.3V winding (with a 5V tap), which would work for the relay supply. Primary is 230V, so all secondaries will be 4.3% higher on 240V. Check the cutout and mounting center dimensions carefully too, they are non-standard.

[hywelg]

Thanks chaps. I had a reply from Edcor (on Easter Sunday!) wanting to know an exact spec. What I dont know is the current rating for the secondaries. I will ask Nik what his are but maybe I need to allow a bit more?

If I was to at some point want to try EL34's I'm guessing I'm going to need bigger filament current capacity. What about HT? I'd like to cover all bases provided it doesn't lead me up a blind alley!

[hywelg]

Check the cutout and mounting center dimensions carefully too, they are non-standard.

I will Martin. I need to find a laydown of the correct spec first then I'll see if I can make it fit. I need a good excuse to buy a compressed air nibbler and this might just be it!

[martin manning]

The typical Fender spec for e.g. 50W Bassman is 330-0-330 @ ~250 mA, and ~3A for the filaments. 12AX7 are 0.3A, 6L6 are 0.9A each, so you need a total of 2.7A. EL34's are 1.5A, so that requires another 1.2, or 3.9 total. Hammond 290EEX would be ok for 6L6, under-rated for EL34 filaments at 3.15A. Magnetic components 40-18097 covers it nicely, with 4A filament winding. Either way you'd need a separate transformer for the relays, but that's not difficult and true-to-style for a Dumble.

[hywelg]

It seems Nik went for the footprint of a Fender Twin Reverb transformer, so nearly every one I've looked at so far has fallen through the existing hole!!

However, if I accept that I need a relay transformer then this fits the bill quite nicely.

http://www.classictone.net/40-18042.pdf

The Hammond291FEX
http://www.hammondmfg.com/pdf/EDB291FEX.pdf
also has the same physical size but the voltages are low at 320-0-320.

Now I've figured out what I'm looking for size wise I think its getting easier.[/code]

[hywelg]

inMadOut have a fender Twin but its 320-0-320, right size (nearly, at least it wont fall through!).
http://www.inmadout.com/download/pdf/TATWIN100.pdf

Taking what Martin said earlier about the 230v tap, could I run the 230 at 240v giving me 336-0-336 on the secondary, but consequent higher filament voltages? Would that stress the heaters too much? . If thats acceptable what about the 220v tap to get me back exactly where the old transformer was at 345-0-345. i.e an 8.3% increase in the specced voltage.