Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: basschops1528 on June 28, 2016, 07:01:46 pm

Title: Fender Champ OT
Post by: basschops1528 on June 28, 2016, 07:01:46 pm

Hey Guys,

I'm getting ready to buy my final bunch of Revibe parts along with parts for a Champ. I'm looking at OT's and PT's on Tube Depot and Hoffmans page and saw that the depot sells a classic tone version rated 5 watts. Am I gonna blow that thing with a cranked Champ? I'm all for saving money but how well is this thing gonna perform against Hoffmans several OT's for this type of amp; how do they compare against themselves? The depot only sells the one (https://tubedepot.com/products/blackface-champ-output-transformer).

Now how about PT's? Here's the depots (https://tubedepot.com/products/blackface-princeton-champ-power-transformer), the hottest of the three. 125P1B 5V/pk less, and the MOJO759 35V/pk less than THAT.

Maybe this can help. I'm looking to build a Champ that can be played clean but has great breakup for that Clapton/Blues sound. I'm going to be using a J J 5Y3 (any good? Voltage drop?) as well and maybe an adjustable NFB pot. Any ideas what OT/PT combo would be good?

Title: Re: Fender Champ OT
Post by: shooter on June 28, 2016, 08:57:49 pm

Quote

final bunch of Revibe parts along with parts for a Champ

If you look at the revibe schematic - verb section, it's basically a champ, so the OT should be the same in both.  Part of the Champs *sound* comes from the slightly anemic OT, so if you *beef* it up, it may change, *that sound*

Title: Re: Fender Champ OT
Post by: PRR on June 28, 2016, 09:07:56 pm

> Am I gonna blow that thing with a cranked Champ?

No. OTs get muddy, not hot.

Note that TD is showing zero stock.

Title: Re: Fender Champ OT
Post by: basschops1528 on June 28, 2016, 09:09:59 pm

Muddy sounds not good. I'll go with Doug's. Now how about the PT? More or less volts for the sound I'm looking for? It's a 5F1 so resistor sag and early breakup.

Title: Re: Fender Champ OT
Post by: Paul1453 on July 02, 2016, 10:49:09 am

Just to give you an idea about my cheesy BB set-up.

Then to maybe ease your mind on little SE OTs.

That is a working 12AX7 - EL34 amp on my BB there.
I know it's hard to believe that mess works.   :l2:

It is using one of my tiny SE OTs, with the EL34 putting out around 9W.
For comparison I've included the 1 Hammond 8W 125CSE I bought new for almost $50.

These tiny OTs sound fine to me with these simple, low voltage, SE 6L6 and EL34 circuits.
So I wouldn't obsess too much about the OT you use on your Champ.
I'm sure whatever one you choose will sound good to you.   :icon_biggrin: