Help me ID this TW OT please

[Ken Moon]

Can anyone verify the primary impedance on this TW OT that Mojo sells?

http://www.mojotone.com/amp-parts/Outpu ... ransformer

The spec sheet says 6k6, but the part number leads me to believe it's actually 5k2.

It looks like a Heyboer tranny, and the label says:

11415 TW-OT-J
HTS-5200-J
9960718

Thanks!

[M Fowler]

That is a 5k2 OT contact rjguitar for Heyboer trannies at much lower price.


https://tubeamparchive.com/viewtopic.php?t=11420

[Jackie Treehorn]

It's a 6.6k. It's Doug Holt's final version of the Pacific 11415. The J is the model with lower gauss laminations from the non J version, which is the one I use. I've measured mine and it is 6.6k. For a long time I thought it was 5.2, though. I think it's just a confusing part #!

If you find out what laminations that mojo ot uses, please post.

[Ken Moon]

Thanks

I think it may be 6k6. There's another OT with the part number HTS-5199 - that leads me to believe it's just a confusing P/N, as you said.

I was thinking this one had the M6 laminations, but that's not a big deal to me, and now I can't even remember where I got that info - these old brain cells don't work like they used to

[FYL]

HTS-5199 is a power transformer.

[FYL]

If you find out what laminations that mojo ot uses, please post.

Probably low permeability => M19, high perm => M6.

[M Fowler]

The HTS-5200 is dual 5k2/6k6

Here is my most recent transformer updated list.

https://tubeamparchive.com/viewtopic.php?t=9866

[Ken Moon]

Thanks, Mark - that's a handy spreadsheet!

It's been interesting reading all the history of the TW tranny clones - it reminds me of some of the efforts to get the first 18watt iron years ago.

Sorry if this is obvious, but why 5.2k for an OT primary? It seems too low for a pair of 6V6s at a safe B+ value, and too high for a pair of EL34s, unless the B+ is run much lower than usual

[JamesHealey]

Ken the Liverpool's were 5k2 and the Express' were 6k6.

Although It does state in the express build guide the later Express' were also 5k2.. not sure how accurate this is.