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tankenburgen 29th August 2005 03:57 PM

vox ac4
i have a vox ac4 and need a output transformer for it does anyone out there have a original vox one for sale

Giaime 29th August 2005 07:19 PM

It's unlikely that you find an original one. Look at Hammond's line of Universal Replacement trannies: they are great.

Trout 29th August 2005 09:10 PM

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.

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.

Tubelab_com 29th August 2005 09:18 PM

I have used that transformer for SE guitar amps with 6V6 and 6AQ5 tubes. I put one in a Gibson Skylark also. They work very well considering the price.

Trout 29th August 2005 10:34 PM

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

Tubelab_com 29th August 2005 11:37 PM

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.

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