They are touted as closely matched quads. Bill is right.
The matching is based upon readings from a tube tester. The Gold Lions are new stock. The Tungsrams and Siemens are new old stock. The Amperex are close on the measurements on a tube tester.
Some of what I just said, I am certain you understand on a much higher level than I do.
I think Bascom (and I) got confused because the BHK only needs a pair of tubes as each tube has two triodes in it.
–SSW
Hard to be articulate when I have a limited understanding of the subject matter. I am more like a parrot, just repeating what others wrote elsewhere. I have BHK Signature 300s – rolling five different sets of quads, which I trust sellers when they tell me they are matched.
Perhaps this will help:
Power tubes are commonly sold in matched pairs (two tubes) or matched quads (four tubes). Power tubes are matched because many amplifiers require using power tubes that exhibit similar plate current (current draw). If the tubes are not matched, the amp will sound dreadful because of the way the tubes are used in the circuit.
A “matched quad” is four tubes of the same type (brand, etc.) with similar plate current intended to be used together in an amp.
Preamp/input tubes typically are not matched. Matched small signal tubes typically do not sound any better, or only marginally better, in a preamp. This is because the tubes are typically used differently in a preamp circuit. But many sell matched preamp tubes, and many buyers insist on them, because audiophiles believe they are “better.” As the charge for matched is typically small, there is no downside getting matched if you like the idea.
The BHK only uses two tubes. Thus, one can roll in a matched pair. But one cannot roll in a matched quad; there is only room for two. Hence the confusion in terminology. 
But, of course, one could have a matched quad of input tubes from which one chooses two at a time to install.
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Thank you. Each BHK Signature 300 requires two tubes. That is why I bought matched quads.
Oh, OK. I was thinking only of my BHK 250, so I was projecting that into my mental image and didn’t think of the 4 needed for a 300 setup.
Out of curiosity, did you try the PCC88’s in the BHK300? How does that sound?
–SSW
Thank you SSW. You said, “each tube has two triodes in it.” Although obvious to you veterans, that is why each tube has two scores from the tube tester? One for each triode? So if the two scores are really close and the other tubes are close to each tube’s score, they are considered “matched.” Also, if I understand correctly, matching is less important in the input stage of an amplifier.
I intend to test all of the tubes I purchased, except for the Siemens and the OEM tubes, to make certain they were preforming well.
The first paragraph should cause anyone reading this some concern about my opinion. I liked the Siemens ECC88 (6DJ8) best. They have a level of detail and clarity not found in the other tubes.
The Amperex 6922 (Holland) and the Amperex ECC88 Bugle Boys sounded very close, but I liked the Bugle Boys slightly better.
I thought the NOS 1971 Tungsram PCC88 7DJ8 and the Genalex Gold Lion sounded very close to each other. They are excellent tubes, but not as good to my ears in my system as the Siemens or the Amperex.
Mark A. Larsen said Thank you SSW. You said, “each tube has two triodes in it.” Although obvious to you veterans, that is why each tube has two scores from the tube tester? One for each triode? So if the two scores are really close and the other tubes are close to each tube’s score, they are considered “matched.” Also, if I understand correctly, matching is less important in the input stage of an amplifier.I intend to test all of the tubes I purchased, except for the Siemens and the OEM tubes, to make certain they were preforming well.
The first paragraph should cause anyone reading this some concern about my opinion. I liked the Siemens ECC88 (6DJ8) best. They have a level of detail and clarity not found in the other tubes.
The Amperex 6922 (Holland) and the Amperex ECC88 Bugle Boys sounded very close, but I liked the Bugle Boys slightly better.
I thought the NOS 1971 Tungsram PCC88 7DJ8 and the Genalex Gold Lion sounded very close to each other. They are excellent tubes, but not as good to my ears in my system as the Siemens or the Amperex.
Correct, the ‘score’ is the measured transconductance value of each triode.
–SSW
Mark A. Larsen said So if the two scores are really close and the other tubes are close to each tube’s score, they are considered “matched.”Yes, many places aim for within 5% to be considered matched.
Anyone have an update to report???
Good morning
is there any BHK mono block users willing to bring there Amps to my new place for an afternoon of comparison listening on my IRS v setup . If yes do you have the tube recommend by BHK as well as stock tube to hear . If not I can buy a pair to have on hand as well .
My intension is to buy them and would very much appreciat testing for a few hours on my setup .
My setup,is in queens ny , woodhaven area . It can be any time or day convient to you .
My current Amps are aragons 8008 BB. oddly also designed by mr King , funny right lol.
My cureent cross over is arriving at ps audio this week for making it balanced as well as the external low pass filter section .
i also have Paul’s new cross over in my system now .
You can bring your own music as well . I do not have any analog source to use but I also welcome it as well but you must bring your own preamp too .
Bringing a friend is fine as well.
The sytem is completely on seperate circuits and P10 ,s and P 5 as well.
Dacs to be used are a msb stack and up to date lampi head dac . I also have many tubes to roll as well. .
thanks in advance for any offerings , and I’ll feed you too lol.
I have BHK recommended tubes for sale on eBay, seller name SLCity. You can borrow them if you like.
First I need a willing person lol. If not I intend to buy them from ps audio anyway. And I can buy the tubes from you. To even hear a bhk 250 would be fine. But thanks for your offer of it was ment to me
Hi.
I am now a PS audio dealer in Manhattan and have the mono blocks in my system.
First I think you should come and listen on my TAD system and if you like what you hear we can talk about a way to get the amps to Queens.
Look me up at www.Triodepicturesound.com
Very cool and glad your there. I’ll call you tomorrow if ok. I would love to come down to your store and Visit.
I have purchased two sets of of Tungstrem PCC88 and I would like to know if I have to change the rail voltage of the BHK preamp?
How about the BHK amplifier?
Thanks from a newbie.
The PCC88 works fine in the BHK amp and sounds wonderful.
The PCC88 is also known as 7DJ8, which shows that it is a seven-volt tube. See page 10 of the manual for how to change the preamp to use a lower voltage tube (it is supplied with twelve-volt tubes).
Thanks magister!
I will give it a try.
I have purchased a pair of of Tungstrem PCC88 premiums with cryo treatment from Upscale Audio and let them play all day ( 10 hrs ) with a burn in cd. Boy was I impressed when I got home. The amp has an even bigger sound stage, deeper and detailed. I am loving the BHK 250. Don’t miss my Emo XPA-1 gen 1’s monos at all!