SE Output Transformer question

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SE Output Transformer question

Postby Jimmy74 on Thu Aug 01, 2013 1:01 pm

I currently have a Blackheart BH5H amp that has been fiddled around with, someone has swapped out the original OT with a generic or homemade (no stickers to indicate model or brand) single ended OT, the primaries measure around 112 ohms. Since Blackheart seems to have gone out of business, I have no way of contacting them to get information about the original OT's. Can anyone here let me know what sort of OT would be ok, any generic SE OT for a 5 watt amp or ???

thanks
J.
His Masters Tone!
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Re: SE Output Transformer question

Postby Jack Hester on Thu Aug 01, 2013 1:04 pm

What tube do you have in the power amp? What is the impedance of the speaker? Don't just put anything in. The OT must have the correct primary-side impedance to match the power tube.

Jack
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because rough men stand ready in the night
to visit violence on those who would do us harm."

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Re: SE Output Transformer question

Postby Jimmy74 on Thu Aug 01, 2013 1:06 pm

well the original OT has secondaries for 4,8 and 16 ohms, the power tube is an EL84.

thanks
J.
His Masters Tone!
Jimmy74
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Posts: 557
Joined: Mon Dec 25, 2006 4:35 pm
Location: Italy

Re: SE Output Transformer question

Postby Jack Hester on Thu Aug 01, 2013 5:07 pm

Here is a discussion on your amp:

http://www.freestompboxes.org/viewtopic.php?f=2&t=2540

Here is an interesting article on some mods:

http://www.guitarnuts.com/amps/bh5h/

And, here is what appears to be the popular retrofit for the OT, bumping your amp up to 15watts:

http://www.tubesandmore.com/products/P-T125ESE

5.2K Primary impedance is what I'm finding out about your OT. You should do just fine with the 5K tap on this, being sure to follow the diagram for your speaker impedance.

Jack
"We sleep safe in our beds
because rough men stand ready in the night
to visit violence on those who would do us harm."

---George Orwell
Jack Hester
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