From his add it looked like had plenty of cases to sort through into sets if he doesn’t sell the whole case lots. I am overloaded with tubes from that family and the BHK has been boxed up since before Christmas.
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I don’t hop in this thread very often but I need to make a quick PSA. We had a customer try out the 6SN7 in the BHK pre with the adapter to make it work. The input stage on the pre began to act a little funky. They sent us the pre for our guys to have a quick look at it and they’re quite sure the tubes caused the board to fail. The heater current for the 6SN7 is twice that of the stock 12AU7 and would certainly cause overheating of the 6V regulator and transformer as well as voltage sag to the rest of the circuit. So, in short, we DO NOT recommend people try the 6SN7 within the BHK pre.
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Thanks for the warning.
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Thanks James. Definitive information is always appreciated.
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It is kind of like putting Monster Truck Tires on your pickup truck. The excess current draw was a concern I had when I saw people do this! Just because you can do something does not mean that you should!
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Except that Bascom said they were OK and he used them and said they sounded good!
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But Bascom knows how to fix them himself if he has a problem as the result of using them.
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We live and learn. Glad you are getting it fixed up. I am still happy with the Conn 12AU7’s.
I was afraid of that. I ordered the Psvanes and adapters to do the change after BHK said it should be ok but hesitated after the failed unit.
Up for sale they must go.
Oh yeah, I’ve already got it back. I was taught the only failures are the ones nothing is learned. The guys were great about it. I sent the tubes in with it but I guess they didn’t have time to test with them as they weren’t opened. Waiting for input boards was the hold up. I used the time to learn my system without the pre and now know I can live happily without the preamp if I’m forced.
Anyway, no big deal just kinda bummer to have the conflicting information. I wonder if Bascom’s unit is built with higher spec parts, and yeah he certainly can fix it but he wouldn’t have just tried them for kicks. He knows what the circuits can support better than anyone.
I’m happy to stick with what I know works but a little disappointed I won’t be able to explore the 6SN7 family of tubes.
I’ve put 55 hours on the refurbed unit and changed to my favorite tubes. The PSvanes are very polite. They do nothing wrong but don’t really shine anywhere either. Too neutral for my tastes but a good baseline option to have for sure. They’re like the wall flower of the party and I like the one that gets up on the table to dance!
I’ve been using 6SN7’s in BHK Pre for a couple of months without any problems whatsoever. It sounds amazing! So good that I modified the cover of the BHK Pre to make it a permanent adaptation. Here is a picture of it…! (Sorry for the dust on it…)
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I made a cover for mine with some scrape metal laying around in my shop, so Ican use the original cover when I switch out tubes. I go back and forth with different tubes.
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It was your guys experience along with Bascom’s post that prompted me to try them. I guess just know that according to PS Audio the 6V regulator will likely give up the ghost at some point running them.
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As Aerosmith sang, "Livin on the Edge’.
@tmcqueen and @mdiaz0429
Is the sound quality improvement worth the risk? (No judgement on my part, just curious about the sq)
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They sounded pretty compelling for the 5 hours mine ran without noise but no not worth the risk of needing to send the unit back for repair again for me plus I’m close to the end of warranty.
They didn’t kill my best 12AU7 but a different kind of good. I also only tried the new Tung-Sol Russian made ones.
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The 6sn7 tubes I had robbed out of another tube amp I have, after a few weeks I put them back in and installed a nice set of 12au7s. I started down this path when I asked Bascom if I could run 12bh7s, they draw .6 amps also, we know the answer he gave. So I ran 12bh7s , 6sn7s and 12au7s, I really like the 12bh7s better than the other two, but they draw double the current also.
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12SN7 should work and draw 0.3a but they don’t seem to be widely available anymore.
6sn7s sound great, but, as I noted earlier here, they run HOT…much hotter than other preamps I’ve had/still have that are designed around the tube.
This scared me, so I run the 12au7, 6922 and pcc88 types only now.
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I’m having fun rediscovering the preamp, fav tubes and fuses. There’s a bright side to most things.
The Tung-Sol 6NS7 didn’t run any hotter than spec’d tubes. I suspect the part the gave up was at it’s limit and didn’t really supply what the tubes called for.