Express Power Transformer

BillyBob · Post by **BillyBob** » Thu Jan 05, 2017 4:14 am

Hello,
Im getting parts together for an Express build.

Any opinions on whether a blackface Fender Bassman 864 power transformer might work OK for an Express build.?

Regards,

Bill

M Fowler · Post by **M Fowler** » Thu Jan 05, 2017 6:23 am

Many have used what they had or could find easily for PT and OT choices.

However; the Express voltage is 600vct so using that Fender PT will have increased HT and plate voltage unless you knock it down some with Zener diode on CT.

I have used the 300-0-300 low power JTM45 PT with a 6K Fender OT on two Express combo amps and they sound like an Express and the owners enjoy them.

Mark

BillyBob · Post by **BillyBob** » Fri Jan 06, 2017 3:23 am

Hello,
Thanks for that info. Ill try that. I know the Express can be a tough nut to crack. Hopefully some reasonable choices for parts should help minimize issues later. For OT Im going with Hammond 1650H. Also not sure if an aluminum chassis is critical.

Regards,

Bill

M Fowler · Post by **M Fowler** » Fri Jan 06, 2017 4:19 am

I like aluminum because it is easier to drill holes and punch holes otherwise, I think it will be fine.

dorrisant · Post by **dorrisant** » Fri Jan 06, 2017 5:33 pm

You may chase some noise with anything other than aluminum... Steel will transfer magnetic coupling, aluminum will not.

BillyBob · Post by **BillyBob** » Fri Jan 06, 2017 11:04 pm

Hello,
Thanks for the message.
Talking about noise and magnetic coupling, has anyone ever successfuly built an Express in a non-KF layout that worked.? Like a Fender or Marshall style layout?

Regards,

Bill

M Fowler · Post by **M Fowler** » Sat Jan 07, 2017 1:48 am

I built two combo Express amps using Marshall type channel chassis.

Also, a Komet 60 in a Fender Bassman chassis. (Big brother to the Express)

Mark

BillyBob · Post by **BillyBob** » Sat Jan 07, 2017 3:04 am

Hello,
Wow, great looking work. Really nice.
So it is possible.
Creative, I never would of thought of doing it like that.

All the time Im thinking Express head and closed back cab.
Whats that combo sound like..?

Bill

M Fowler · Post by **M Fowler** » Sat Jan 07, 2017 5:03 am

The Combo sounds just like my regular Express heads I've built just easy for the gigging guys to carry in and out.

When I gigged I preferred a head and speaker cab myself. Had to carry all the other crap in so an extra speaker cab wasn't a big deal and then I could choose a 212 or 412 cab.

I used silicon tube rings on the power tubes to dampen vibration but didn't have any problems reported back to me.

Mark

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