Just a thought

[jon]

Looking at #183. HAD seems to be so careful in component selection, why did he use a PT that does not have enough filament capacity for the amp?

[Max]

Looking at #183. HAD seems to be so careful in component selection, why did he use a PT that does not have enough filament capacity for the amp?

Perhaps because he's careful in component selection and for whatever reasons thought this kind of selection to be in best accord with his plans in regard to the overall performance of this amp?

Cheers,

Max

[talbany]

Looking at #183. HAD seems to be so careful in component selection, why did he use a PT that does not have enough filament capacity for the amp?

Jon
It is a very common practice for transformer manufactures (of tube amps) to list power requirements on their spec sheets somewhere between 35 to 50% below actual current handling of the listed transformer...
Most of the modelled replacement transformers (Showman/Bassman) were originally over spec'd..When we order a custom power transformer I always allow for 50% over spec on both filaments and B+...I'll bet my left one Dumble knew the exact power capabilities of that transformer..



Tony

[amplifiednation]

I thought the extra transformer in 183 powered the relays, not the filaments. Have I missed something?

Or are you suggesting he should have had a custom transformer built with more filament current to power the relays?

[martin manning]

It's the EL34's vs. 6L6, 1.5A vs. 0.9 for the filaments.

[ic-racer]

I built my HRM using EL34 x 4 with a Hammond PT rated at 5.5A filament and so far so good...

[amplifiednation]

It's the EL34's vs. 6L6, 1.5A vs. 0.9 for the filaments.

Oh I see...because the Magic Parts PT was a replacement for the Fender twin and meant for 6L6. I never noticed that, I figured he borrowed Music Man, Tray nor, or Marshall transformers for those builds.

Was the OT in 183 also originally designed for 6L6?

What about the Bluesmaster and other EL amps??

[ic-racer]

It's the EL34's vs. 6L6, 1.5A vs. 0.9 for the filaments.

Oh I see...because the Magic Parts PT was a replacement for the Fender twin and meant for 6L6. I never noticed that, I figured he borrowed Music Man, Tray nor, or Marshall transformers for those builds.

Was the OT in 183 also originally designed for 6L6?

What about the Bluesmaster and other EL amps??

All the pictures I have show TF-130 (Fender Twin) Power Transformer in Bluesmaster and Non-Bluesmaster HRM el34 amps.
Perhaps someone will chime in with exceptions.

For example here is a non-Bluesmaster HRM in the early #200 range that I based my build on. You can see the EL34s and the TF-130 sticker.
[IMG:800:535]http://img.photobucket.com/albums/v670/ ... former.jpg[/img]