Princeton reverb with vibrolux reverb transformers!?!

[bruno]

Hi guys,

I have the need for a small, portable fender with reverb, and my favorite in terms of sound as always been the princeton reverb. However I do have a set vibrolux reverb transformers hanging around, this will automatically make the amp heavier, but my question is how much will it change the overall tone of the amp, if I use the same schematic as the princeton?

The OT is 4000ohms primary but it has several secondary taps, so I intended to still use 6V6s and compensate the ratio by pluging the amp into a 8ohms speaker using the 16ohm tap.

Your thoughts are welcome, I don't really want this to sound like a deluxe reverb or a bigger amp. Should I go through or just get smaller transformers?

[6bq5]

it probably will sound a bit "bigger"/cleaner,   but i think a lot of the princeton character will still be there just because of the cathodyne p.i. and no choke as well.     rh

[HotBluePlates]

The OT is 4000ohms primary but it has several secondary taps, so I intended to still use 6V6s and compensate the ratio by pluging the amp into a 8ohms speaker using the 16ohm tap.

You'll need to apply 8 ohms to the 4 ohm tap to reflect 8k to the primary, but you probably just mis-typed that.

Let's assume your transformers are spot-on replicas of the original Vibrolux Reverb transformers. The blackface Princeton Reverb had a 340-0-340v PT and a 5U4 rectifier, where the Vibrolux Reverb had a 315-0-315v PT and a GZ34 rectifier.

Assuming US voltages, 315/110 = 2.864 * 120v = 343.7v. So happily, applying modern wall voltage to an accurate Vibrolux PT results in old-style secondary voltage perfectly suited for a Princeton Reverb. Though you might see some variation on the proper rectifier for the PR, I always used a 5U4 in mine; my first tube amp was a '67 Princeton Reverb, and that was the specified rectifier in that amp.

I agree with 6BQ5 that much of the Princeton character will be retained by the power supply and phase inverter style. And original blackface Princeton's used a Jensen C10Q speaker. Don't use a "too-good" speaker that has a bigger, clearer sound than the original, and you'll be fine. I haven't done a speaker shoot-out, but the reissue Jensen C10Q sounded reasonably close to originals to me, after some break-in. I've used maybe 3 C10Q's in the past. They're not 100% the same, but a new speaker will have a hard time matching a 40-yr old original. And you can't beat the price of the reissues.

[bruno]

Thank you 6bd5 and hotblueplates,

Yes the secondary tap was a mistake I meant 8 ohms in the 4 ohms tap.

I intend to keep everything the same even the 10" speaker, I think the C10Q is the best speaker the current jensen reissues have going on, but even their alnico ones sound good once they're broken in.

The transformers I have are vibrolux reproductions sold by mojo, I suppose these are made by heyboer. I will try and do the princeton with these than, that will save me some money.

Thanks guys

[jjasilli]

Also, you might like 6L6's in there.  Worth a try.

[DummyLoad]

run it with 2 pair of 6V6. switch out a pair if not needed and double the speaker load.

--DL