Search found 4 matches

by squicker
Wed Aug 03, 2016 5:36 pm
Forum: HT-5
Topic: Blackstar HT-5 Tube Swap
Replies: 146
Views: 221244

Re: Blackstar HT-5 Tube Swap

The problem is most people don't even understand how electricity works....much less how a push-pull pair of electron tubes amplifies a signal. Couple that with the fact that there are lethal voltages involved and, yea...it makes sense that B* isn't going to layout a how to on biasing an amp. There'...
by squicker
Tue Aug 02, 2016 10:36 pm
Forum: HT-5
Topic: Blackstar HT-5 Tube Swap
Replies: 146
Views: 221244

Re: Blackstar HT-5 Tube Swap

Here's the secret: If you ask them for biasing information, they automatically know that you don't know what your doing. :mrgreen: The only proper way to set bias is to look up the plate dissipation rate of the tube type, then measure plate voltage, do the math and adjust bias current accordingly. ...
by squicker
Tue Aug 02, 2016 5:03 pm
Forum: HT-5
Topic: Blackstar HT-5 Tube Swap
Replies: 146
Views: 221244

Re: Blackstar HT-5 Tube Swap

Yes, the amp will still need to be biased. The only exception is if you purchase a matched pair of tubes, install one and then bias the amp. In that case, you can swap in the second (matched) tube without biasing the amp. OK thanks, that is as I thought. Turns out my amp has a TAD power tube in it ...
by squicker
Mon Aug 01, 2016 1:17 pm
Forum: HT-5
Topic: Blackstar HT-5 Tube Swap
Replies: 146
Views: 221244

Re: Blackstar HT-5 Tube Swap

Just to be clear on biasing. I've got an HT5-RS, which I believe has the Electroharmonix 12BH7A power tube installed. I've just ordered a replacement (think the valves just died at 4 years old) Electroharmonix 12BH7EH Gold, which I believe is a direct replacement. Even though the valve is same brand...