MOV for Express Build

[camden_guitarist]

Hello,

I'm building myself an Express but I live in France so some of the components have to be converted for european use, such as the Power Transformer and the MOV, which value should I use for the MOV? And for the transformer; would a 50W JCM900 be sufficient?

Thanks for any help

Paul.

[UR12]

Hello,

I'm building myself an Express but I live in France so some of the components have to be converted for european use, such as the Power Transformer and the MOV, which value should I use for the MOV? And for the transformer; would a 50W JCM900 be sufficient?

Thanks for any help

Paul.

The 50w part is OK but I would think that the JCM900 tranny would be running B+ voltages that would put you over the 390 - 410v used on an express. I can say I have used Trannys putting out about 470v on one of my Express builds and that amp turned out great. As far as the MOV is concerned if your are running 240vac power then get a 250 -260v MOV or one that is rated about 10 - 20 volts higher than your AC.

[camden_guitarist]

Thanks UR12, so I'd still do better to get the Tone slut set with the PT for Europe? I'm having a bit of trouble reaching the people I have been in contact with for parts, is something the matter with Allyn Meyer coz he hasn't replied to me for the chassis, I was gonna get one from him.

In the meantime I have a friend that has showed some interest in me building my own amp, he helped me build a small practice amp and he gave me an old chassis to work with for the Express, I had to adapt my layout a bit but I think it'll work out just fine, the chassis is drilled for JCM900 trannies hence the question earlier on, if I could just put in a set of JCM900 trannies all my problems would be solved in one go, you see.

Also, and there's the kicker, I'm having as well problems getting the right hookup wire, and importing it from the states is apperently a no no, I found some on Mcmaster Carr but they won't deliver. Any ideas?

Thanks for your answer earlier on by the way.

Cheers,

Paul.

[Allynmey]

Paul, I haven't seen anything from you. Did you send me a PM? and E-mail? I check through both and don't see anything. PM me what you want and I'll send it right out.

Allyn

[camden_guitarist]

Hi Allyn

Well, I just checked my SENT folder in hotmail and I still have all the request mails, as I said I already have a chassis now, donated by my friend, it's from an old Carlton combo amp, I'll use the cab as well to build myself an Express combo for the time being (I'd have loved to have build it in a cheap tweed copy but alas).

If this one works out ok, I will be back for more don't worry about that. Do you have an idea about a good european replacement for an Express clone? Mark told me as well that Brian Wallace's Stancor copy would be the OT to go after.

Well, thanks for the heads up and you'll be hearing from me soon enough.

Cheers

Paul.

[UR12]

is something the matter with Allyn Meyer

Well in a word, Yes. You would have to be crazy to take over this place and he did so I guess that's enough said

In the meantime I have a friend that has showed some interest in me building my own amp, he helped me build a small practice amp and he gave me an old chassis to work with for the Express, I had to adapt my layout a bit but I think it'll work out just fine, the chassis is drilled for JCM900 trannies hence the question earlier on, if I could just put in a set of JCM900 trannies all my problems would be solved in one go, you see.

Like I said if you wanted to you could use the power tranny and while it wouldn't be an exact clone I think you could get some good results. The OT is another matter. Someone can correct me if I am wrong but I am thinking that the JCM900 is probably around 3.5k as far as impedance goes. 7K would be close enough to 6.6 k to get the job done but you would have to re-lable your speaker output taps from 4/8/16 to 8/16/32. If that wouldn't be a problem loosing the 4k tap then you could give it a try and see what happens. Experimentation is 1/2 the fun anyway. One of the best sounding Express amps I ever built had a plate voltage of 475VDC and an OT with a 7k primary. It was built out of all junk box parts so we called it the Junkyard Express.

Also, and there's the kicker, I'm having as well problems getting the right hookup wire, and importing it from the states is apperently a no no, I found some on Mcmaster Carr but they won't deliver. Any ideas?

Thanks for your answer earlier on by the way.

Cheers,

Paul.

Any kind of either stranded or solid 18 to 20 guage hookup wire should work just fine.