Bad Cat Cub ii OT Question

[bfrederi]

Hi all,
Was working on a Bad Cat Cub ii for a friend that had a pair of hosed EL84's.
Tubes were replaced and all is working fine, puts out about 15 - 16 watts into 8 ohms. Along the way I checked the OT primary P to P impedance (just for future reference) and found it to be ~4K (3.96K Measured) into 8 ohms. It in fact measured allot like many AC30 OT's I have documented over the years.
Of course I was expecting more like 8K P to P impedance so I have double and triple checked. I have checked both the 4 ohm and 8 ohm tap and used a couple of different methods and still come out to a turns ratio around 22.2:1 with the Impedance switch set to 8 ohms.

Anyone else run across this? Or does anyone have a Cub ii they would be willing to check?

The transformer is stamped TDS 1165 and the output taps are as follows:

BLK- Com
Orn - 4 ohm
Grn - 8 Ohm
Light Blue - 16 ohm (not used)

Any info would be appreciated......
Thanks,
-Brad

[harryk]

I am just thinking to start a Matchless Lightning 15 project and faced the same question concerning OT impedance. Lightning is a derivate of Vox AC15 and I think that this BadCat is the same origin. I seeked information from net and come to conclusion that this OT should really be 4 kohm. Many people say that Lightning is a very good sounding amp and I am wondering if one part of that sound is so called OT mismatch. Harry

[CaseyJones]

Matchless underloads all their amps, it's almost a Matchless trademark. Mentally I sort Matchless and Bad Cat into the same category. I like correctly loaded outputs but I must admit that stressed EL84 tone is cool, too.

It comes down to tone. If you like how it sounds (and you can stand a little shorter tube life) leave it alone. If you don't like the tone then off you go on a quest for an OT that results in the correct load and has a tone you like.

[bfrederi]

Thanks Guy's, much appreciate the input!
I think your right.
Got ‘a say I really liked the way it was sounding......and yea it is very much like looking at a Matchless chassis on the inside.

I talked to James at Bad Cat, said he did not know off the top of his head what the primary P to P Z of the OT was but did say the EL84's are "run hot" in that amp.
I think my friend needs to be prepared to keep EL84 pairs on hand.

BTW anyone know who manufactures the transformers for Bad Cat?

Thanks again.....
-Brad

[daz]

.

BTW anyone know who manufactures the transformers for Bad Cat?

Thanks again.....
-Brad

TDS - Transformer design and supply:
http://transformerdesignandsupply.com/

They do all the matchless stuff too. Before buying westlabs stuff, consider TDS, they're exactly the same but cheaper.

[bfrederi]

Thanks daz.... appreciate the info

Have you had anything custom wound by TDS?