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New Toy, Black Mystery Box



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My latest Ebay find. Sawe this on Epay and wanted it pretty bad, so I put out some cash for this one and got it. I like to play with things I haven't seen before. What I saw on the Ebap auction was 9 little soldiers peeking up at me. I figured one was the keying tube and I was right. The other 8 are 6gk6 tubes which are 6bq5's with different pinouts. Yep, 8 6gk6's / '6bq5s' all in parallel. I was kinda hoping they would be push pull, but that's ok, still an interesting box. I don't know if this mystery box is home made or not, but it is well made. Good engineering, except no bleeders. However, since the HV is turned on thru the keying relay, I think the designer may have did that on purpose. If it used bleeders, the HV caps would be discharging when unkeyed and hence would pull high current to charge every time you keyed. That ain't good. However, on the other side of the coin, with no bleeders, those caps will hold a charge a very long time. Nothing is pulling the down. A long time ago, I got zapped by a video game monitor that had been unplugged for months. They don't have bleed either and ZAP. However, thankfully, it made me do the funky monkey dance, but I was OK. I guess the question on this one is to bleed or not to bleed.
This amp has HV going to the screen and is grid driven aka Turbocharged. However, the HV is only running at 550V which is pretty low for a tube amp. I think the builder was going for clean power vs max power. Most amp builders do just the opposite. Run the HV way up, get max power out, but sacrifice clean output and longevity. With the lower voltage on the plate, and 8 little soldiers only putting out 60 watts deadkey and 160 swing, this amp runs clean and should last a long time. I only had to replace the electrolytic caps on this one. Everything else worked. Pretty clean for a fifty-year-old girl too. I like swinging, clean, good running amps, so of course, I like this one a lot.
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Audio
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