Hi Guys,
First post here. I just had a service job done on a Blackheart BH5 guitar amp. I had blown the output transformer by playing at full blast with a full band a little too often (oops haha).
So I decided to try out a different OT that I had seen recommended by a few different sites - a Hammond 125ESE.
Following the job the amp is really noisy and squealing quite badly as I turn up the volume. The actual pitch of the squeal changes as I turn up the volume.
I thought maybe it could be the new valves, but when I opened up the amp I could see that the OT was slightly off axis from being 90 degrees perpendicular to the Power Transformer.
![IMGDEAD]](/community/proxy.php?image=http%3A%2F%2F%5BIMGDEAD%5Dhttp%3A%2F%2Fi49.tinypic.com%2Fn5rkap.jpg%5B%2FIMGDEAD%5D&hash=e09620dcde2afe827c11e94015415ec8)
Hopefully the above link works.
Could this be responsible for the noise that I'm hearing?
First post here. I just had a service job done on a Blackheart BH5 guitar amp. I had blown the output transformer by playing at full blast with a full band a little too often (oops haha).
So I decided to try out a different OT that I had seen recommended by a few different sites - a Hammond 125ESE.
Following the job the amp is really noisy and squealing quite badly as I turn up the volume. The actual pitch of the squeal changes as I turn up the volume.
I thought maybe it could be the new valves, but when I opened up the amp I could see that the OT was slightly off axis from being 90 degrees perpendicular to the Power Transformer.
Hopefully the above link works.
Could this be responsible for the noise that I'm hearing?
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Ha. For some reason my entire thread has just disappeared.
I just had a new Output Transformer installed, and my BH5 guitar amp hasn't stopped squealing since.
Here's a pic of the install job:
Any advice?
I just had a new Output Transformer installed, and my BH5 guitar amp hasn't stopped squealing since.
Here's a pic of the install job:
An externally hosted image should be here but it was not working when we last tested it.
Any advice?
Frank has a good point as wiring the primary (or secondary for that matter) the wrong way will invert the feedback signal and cause this problem. A big presumption though that this amp uses what should be negative feedback, bearing in mind it is a guitar amp built more for raw grunt than audio perfection. But as this problem has only occurred since changing the OT then a very valid point and worthy of a check. The howling varying with the volume control certainly steers ones thoughts in this direction. Just another thought though, isn't that output Tranny a little close to the ECC83 on the input? I know it has a screening can, it's just that it doesn't seem right somehow, let's say I would not have designed the layout in that way. Les
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