You are for a treat with the PHK pre, if your experience is anything like mine. There isn’t much to do except let it break in a good long time, as with most PSA gear.
I personally like to do the break-in before changing tubes so that I can really hear whatever difference the tubes make. But some guys are eager to get the best sound from day one; it’s up to you. Just remember that if you install the PCC88s you need to change both the voltage and bias settings. The picture in the manual isn’t the clearest, but once you get the top off it’s more obvious. Needlenose pliers are helpful in moving the jumpers.
My former preamp was single-ended and I found that changing to balanced interconnects was an improvement.
Edit: speeddeacon submitted his answer while I was typing; sorry for the duplication.
I’ve tried Telefunken NOS 12AU7’s in my unit. I found my BHK sounded too lean in the midrange for my liking. Not as lean and strident as the stock Psvane’s (which are frankly unacceptable in my opinion), but no joy for the genre of music I listen to most, vocals and jazz. My personal experience leads me to conclude this design simply sounds better with 6 series tube types run at 5 mA bias. See my previous post on using NOS Siemens 7308s. The BHK is exceptional with these tubes. I’ve since tried NOS Siemens 6922s (A-frame getter, 1974 production). Same impression: vibrant knockout beautiful midrange and deep, powerful bass. I’d encourage others to at least consider adding Siemens to your list. Something special, so much so I’m buying Siemens 6922 backups to go with my 7308s.
After some less than satisfactory experience w/ some 6 and 7 series tubes I opted for some 12AU7 tubes. The CIFTE 12AU7 is great with a wonderful 3d sound field on my system. The MULLARD CV4003 / 12AU7 is full bodied and perfect for pre '72 Grateful Dead. Just plugged in some Siemens 7308 tubes and have Kind of Blue cranked. Nice combo.
Really like the Siemens 7308 combo - much more air than the Tungsrams.
I’m finding the Tungsram’s to be a bit dark in upper mids and possibly lower treble. There’s just a little veil or something which is most apparent on piano and female vocals, for example. I’d like to swap to one that adds brightens things up a bit. Which tubes have accomplished that of the ones you rollers have tried.
I briefly swapped the Telefunkens out for the Tungsram. Both nice, but the Telefunkens seem to have more air and openness. I am going to try the Brimar 12AU7 and Mullard. [Links are provided solely for convenience, not because I get anything from them; I don’t.]
And then, just for fun, I am going to try something completely different: the original Psvane T-II 12AU7 [at least, the originals look like T-II series]. I have always liked their 6CA7, better than the Shuguang Treasure Black Bottle in my old Decware equipment. I am putting these tubes in the T2 I am having built for my Stax. I have several of these, and am going to see how they fare after trying the other 12AU7. Wouldn’t that just be the kick. And reminding myself why tube rolling drove me nuts before. At least I don’t work any more. At work.
So the consensus (including from BHK) for using Tungsram PCC88/7DJ8 in the preamp is to move 5ma for the bias - ok. Changing the voltage pin is a given, but I started wondering about the bias only because Kevin Deal at Upscale suggests (in his video) that the bias should be left at 4ma.
I have to say I get a little confused when reading this thread as to whether posters are regarding the BHK Preamp or amps.
I’m taking the plunge and ordering a pair of Signature 300’s next week. Are the tubes in the amp the same as the preamp?
What tubes have been favored int the amps?
The BHK power amps take 6/7 volt heater tube types of the 6922 Genre. They are shipped with Genalex Golden Lion 6922. A favorite for the best sound is a Tungsram 7DJ8/PCC88. The preamp can be set for 6/7 or 12V tubes. It is shipped with Psvane 12AU7 tubes. The preamp also sounds best with that 7DJ8/PCC88 tube. However, there are differences of opinions on which particular brand of tubes sound the best but what I said is my opinion. Hope that helps!
I am waiting for my BHK preamp to arrive. Kevin from Upscale audio took care of me well and included a set of BHK select tubes!! I should have on friday. I’ll burn in the unit with the stock tubes and after several hundred hours I’ll roll in the BHK select tubes! I can’t wait to listen to this preamp, as I have the BHK 250 and DSD dac!
I briefly swapped the Telefunkens out for the Tungsram. Both nice, but the Telefunkens seem to have more air and openness. I am going to try Brimarthe 12AU7Mullard and . [Links are provided solely for convenience, not because I get anything from them; I don’t.]
And then, just for fun, I am going to try something completely different: the original Psvane T-II 12AU7 [at least, the originals look like T-II series]. I have always liked their 6CA7, better than the Shuguang Treasure Black Bottle in my old Decware equipment. I am putting these tubes in the T2 I am having built for my Stax. I have several of these, and am going to see how they fare after trying the other 12AU7. Wouldn’t that just be the kick. And reminding myself why tube rolling drove me nuts before. At least I don’t work any more. At work.
Wondering what you thought about the Brimar 12AU7 and Mullard when you tried them. I have a pair of Brimar 12AU7 tubes nicely broken in that I really like.
Maybe this has been asked or addressed before, if so sorry. I see in the BHK there is a clock that is keeping track of the hours on the tubes. Is this re settable in the event of rolling in new tubes?
Yes. I did it when I changed tubes in the BHK Pre but don’t remember the details and I’m not at home (and if I was I would be reluctant to look because I’d probably accidentally reset the counter–it didn’t take much to do it). It does involve going into the set-up menu and then going to the counter readout.
