New BHK Pre Owner and Having Issues

Up and running…that’s wonderful…!!!

Happy for you that finding the culprits were so easy…congrats

I know about impatience…I’ve found myself in the same boat a few times
am familiar with the itch…

Happy listening


Now that you’re back up and running and you have a stock of spare tubes, one additional bit of knowledge to impart. This is a ‘dual triode’, meaning internal to each tube there are two triode sections. When deciding which tubes to pair from my tube box, I have quite a collection, I look for the best match overall across all four triode sections in the the pair. As a BHK owner I have found the Pre to be rather sensitive to triode matching and I never use a pair that hasn’t been matched across all triode sections to 5% or better.

Yes, that does mean I’m very picky about the tubes I buy as matched pairs and I haven’t hesitated to return pairs that don’t meet my own criterion. My favorite vendor of NOS small signal tubes is TubeWorld. Where the exact pair you are going to plunk your money down for is pictured and where Gm for each triode section is published. You can do the matching calculation for yourself.

Enjoy your BHK Pre. Now you are on the tube roller coaster and that is a whole new adventure!


The 7 in “7dj8” indicates 7 volts.
The 12 in 12AU7 indicates 12 volts. Your stock Psvanes are 12 volt.

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Sweet, sounds like the swap went well. After you get through some more albums, let us know if it starts acting funky again. And thanks @RonP for the guidance. He is exatly right about the tube voltages. For the 7DJ8s, if it wasn’t clear already, you’ll want the voltage jumper to be set to 6V.

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It’s the start of a delightful journey. The Tungsrams are great tubes, though slightly hissier than the PSvanes.

If you ever decide to swap the spares in, make sure you use the correct voltage and current setting for the Tungsrams. It’s 6V and 5ma.

The stock PSvanes (if Upscale didn’t swap in the Tungsrams initially) are 12v, 4ma.

The manual shows where the jumpers are.

All, thanks again for the assistance. After many records and a few movies I’ve had no issues.

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Always a pleasure. Glad it’s working properly now!