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Hoffman Amps Forum image Author Topic: Howl and Squeal on fire up  (Read 3281 times)

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Offline stingray_65

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Howl and Squeal on fire up
« on: September 12, 2010, 10:20:14 am »
Hi fella's

Ok I know flip the brown and blue wires on the OT. (did that and no howl)

Heres the issue, in my haste for a neat lead dress I've cut the blue wire too short to"flip" to the other tube socket.

I don't want to splice in 3/4" of lead to make it reach.

Can I "flip" the leads  from my PI instead?

Ray
My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention (H. Lamarr)

Offline sluckey

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Re: Howl and Squeal on fire up
« Reply #1 on: September 12, 2010, 10:30:28 am »
yes

I never trim the OT leads for an amp that uses NFB until I know which way is correct.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline Fresh_Start

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Re: Howl and Squeal on fire up
« Reply #2 on: September 12, 2010, 11:12:18 am »
+ I never connect the NFB at all until I'm getting good sound out of the amp during startup.

Potentially dumb question:  could you flip the leads on the primary side of the OT and get the same result?

Chip
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Offline stingray_65

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Re: Howl and Squeal on fire up
« Reply #3 on: September 12, 2010, 12:21:40 pm »
yes

I never trim the OT leads for an amp that uses NFB until I know which way is correct.


I only trim them when I want howl on start up  :angel

LOL thanks for the confirmation Steve.


Chip,
You can, I have BUT! you can't use the other taps

Thanks
Ray
My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention (H. Lamarr)

Offline eleventeen

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Re: Howl and Squeal on fire up
« Reply #4 on: September 12, 2010, 01:50:44 pm »
Quote
I never trim the OT leads for an amp that uses NFB until I know which way is correct.

They taught us that in the 1947 Airco Welding School Course.

 


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