Ampeg Portflex B-12XT Power tx

[blindboybenton]

Hi all

My customer has given me a Ampeg Portflex B-12xt
The mains transformer is 110v and he wants to get a 240v ac transformer for it. he don't want to go down the road with an external transformer
My question did ampeg make a version of this amp for the uk market? He wants to keep it original if possible and then if one cant be found, ill get an after market one
Also never having repair an old ampeg before. There is a black square plastic box on the turret board connected across V6A and V8B. What is it ? The one in this amp is fairly shot. Can anyone help with a tx for the uk market for this amp

http://www.drtube.com/schematics/ampeg/b12xt.gif

BBB

[Steve Conner]

Fliptops.net do a dual voltage replacement PT but it isn't exactly cheap.
Power Transformer PT12XA for Ampeg B18N, and X Seires - Product Details

[blindboybenton]

Thanks steve

I might want an after market tx at that price

john

[Jazz P Bass]

Balance out the cost.
It looks original.
It's what you want.

[J M Fahey]

There is a black square plastic box on the turret board connected across V6A and V8B. What is it ? The one in this amp is fairly shot.

It's a (probably self made) vibrato modulator, containing 2 LDR and 1 neon lamp.
Why do you say it's "shot"?

[J M Fahey]

I find the Fliptops one inexpensive, considering what it is.

For reference, Hammond Transformers, which offers high quality at "normal" proces, not audiophool inflated ones, has a very similar one: 374BXP 750V CT, 201mA (sic), "universal primaries" (from 100 to 240V), generous 5VAC and 6.3VAC windings, potted inside a drawn steel case, of course (just what the doctor ordered) for a mere U$389 .
How's that?

Hammond Potted Power Transformer 374BXP

[blindboybenton]

Hi

I say its shot because the plastic case is falling apart and wires have snapped off. Not sure if its self made as its on the schematic

bbb

[J M Fahey]

I mean selfmade by Ampeg, same way as the neon-ldr "roaches" were self made by Fender, i.e. not a part you could buy ready made at the Mouser equivalent of the day.

Post a picture.

You can probably rebuild it.
The LDR *might* still work; the neon bulb must be certainly worn .

[Tom Phillips]

Fliptops has the old style Ampeg tremolo modules too. See Vibrato Module VM-1 ror Vintage Ampeg Amps - Product Details.

[Randall]

I am surprised I don't see more people getting these rewound. I had one rewound and potted back in the original case for around $200.

[Leo_Gnardo]

I am surprised I don't see more people getting these rewound. I had one rewound and potted back in the original case for around $200.

That's a knock down price for a filthy awful job. I've done the melt, replace, repot, repaint a couple times on Ampeg transformers and it's deep in the no fun zone although it does have its mad scientist aspect. Mind telling us where you get this done? Thanx in advance.

[Randall]

A guy in Orono, Maine

Transformer Rewinding Service
xfrmrs@roadrunner.com
207_nine four two _ 5745

I've had two rewinds from him, one a B-15 PT, and the other I forget. Very happy with both.

[Ted]

You're in the UK aren't you?
I got a new (240V) one wound and potted by Transformer Equipment in Deal a few years back. You still have to melt the pitch get the old tranny out. I seem to remember Enzo had an Ampeg Service book with the original specs. If you search the forum you may even be able to find my conversation with him. (I couldn't seem to see it) They charged me £126.80. Which I thought was a serious bargain.

Spec was:
800 VAC CT, 200mA, 5VAC@3A, 6.3VAC@5A

[blindboybenton]

Hi Ted

I use that firm in kent and they told me that they can't do it. due to the in casement The amp has been and gone now with a step down tx. Im in Dorset where abouts are you ?

BBB

[Ted]

Hi Ted

I use that firm in kent and they told me that they can't do it. due to the in casement The amp has been and gone now with a step down tx. Im in Dorset where abouts are you ?

BBB

That's odd. Becasue they definitely did one for me two or three years ago. I had to dismantle the original and clean it up. I have one of those little electric ovens I use for unpotting B15 Transformers.
But they wound and potted one for me.

I'm in London.

T.