vox ac4

Theres a place out here in chicagoland that has a OPT that should cover that amp well.

According to the Vox AC4 schematic I have, You need a 5K primary & a 3 ohm secondary.

This Transformer Should cover that fairly well.
Also comes in 2 mounting configuations,
TF103-48 is now available with EITHER 2 3/8 inch mounting hole centers (fits silverface & blackface Champs from 60's & 70's) and 2 inch mounting hole centers (fits later model Champs). Check the distance between the transformer mounting bolts on your amp before ordering.

I have used a couple of these and have no complaints on a couple of homebrew guitar amps for my brother.
Interestingly.
This latest version now includes a screen tap for optional pseudo-triode "ultralinear" operation. If you don't need it, just tape up the extra wire.

For $15 plus S&H not a bad replacement option.
Gene
 
Hey Tubelab,

Have you seen or tryd the new opt they are carrying now?
Primary impedance is 4200 ohms with screen taps @ 40%, secondary is 0-4-8 ohms. Rated 35W 50Hz to 20KHz -1 db.

This type of transformer can be used with many tube types, such as pairs of 807, 6L6, KT66, EL34, push-pull parallel (quads) of 6V6's or EL84 and others. Intended for push-pull use. May be used with tubes wired for pentode, triode, or "ultralinear" pseudo-triode operation.
Max DC per side (suggested) 100 ma.

That Looks to me to be about the best value in a guitar OPT I have sen in some time! Especially concidering the warranty.

35 bucks plus SH,, NICE
Gene
 
Transformers

I have used their SE transformers, and their cool new universal driver transformers. Look for an H bridge amp on my web site in the coming months using that transformer. I have not needed any PP transformers recently.

I bought 200 surplus Schumaker PP transformers when ADA went under, and haven't used them all up yet. I have been putting them into everything except high end stereo amps with good results. There is even a pair of them in my 300Beast 300B PP stereo amp.

I need a SE transformer that can handle over 100 watts, work on 2000 volts and have high end specs for an 833A stereo amp. You don't buy these at Wal-Mart. I had a transformer winder make me a custom transformer, but the prototype rolled off at 17KHz. I guess I will just have to build myself that 200 Watt SE guitar amp after all, since I only have one of these. The prototype amp sounded absolutely wicked.

http://www.tubelab.com/833SE.htm