Tubes for BHK to tame brightness

In “ask Paul” one of the forum members advised me to join a forum about the qualities of tubes. In particular tubes that tame a bit of brightness coming from BHK. I think it is a personal problem (better: a problem of my ears) but if there might be a solution in using other “flavored” tubes.I would like to give it a try. As I can’t find a forum with this subject I have created one myself.
So, ladies and gentlemen, let’s roll.

Might be helpful to specify whether you’re asking regarding the BHK power amp(s) or preamp.

Your most efficient route would be to go to a site that specializes in tubes. I always found Upscale Audio’s website very easy to navigate, with pretty reliable descriptions. And he’s a PSA dealer so a phone call would probably set you on a happy path.

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Hallo Audiobill,

Sorry you’re right. I meant BHK the poweramp.

Nice weekend,


It would probably help to know what speakers you are using.
I have found when changing components that I have had to readjust my speakers. Have you tried a little less toe in? If not, give it a try, it is simple to do and costs nothing. It never hurts to put a couple of pieces of masking tape on the floor, that way if changing the toe in doesn’t do it, you have the markings to get back to the original location.
Tubes may help, and as recommended above Kevin Deal at Upscale is the tube guy. I have been told that he can be a bit hard to deal with over the phone, you might want to start with an email.

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Thanks a lot jeffstarr. My speakers: Harbeth Super HL 5. I have sent a mail to Upscale and we will see. Have a nice weekend,

Frans Gommers

You can also try tweaking your cables. You will find copper can tame some brightness. Tube tweaking can be difficult as you can’t really try them out.

I have talked to Kevin many times over the years and he always sounds like his head is ready to explode, but he knows what he’s talking about. And forget email----I’ve never gotten an answer. Call----be strong.


You can also contact Brent Jessee at I have emailed him many times and gotten an expeditious response. I have purchased many tubes from him. Good guy, gives good advice and sells great tubes – all online. No attitude.

If your looking to tame the amps down then the Matsushita’s will do the trick in either the 6DJ8 or 7DJ8 versions. Kevin has them but so do other dealers like Brent and Andy at Vintage Tube Services.

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Also, the Tungram 7DJ8’s are really worth looking at. And well priced too.


I’ve found the sound of the Tungsram’s to be typical of the Eastern European tubes of that era which is to say they won’t tame any brightness issues. The Matsushita’s were made in a Japanese plant set up by Mullard and are similar in sound to Mullard.

I’ve owned tubed equipment since the 1980s… even DACs (Sonic Frontiers)… A few tips:

1 - Opinions… wow, everyone has them. I will say that you can begin to get “directionally correct” information on the forums. I found Audiogon’s forums not bad for tube information, but there a many places.
2 - Tube dealers… lotsa opinions on where to buy tubes and hence the advice you get from the dealers. Currently, I am a fan of Upscale Audio simply because I like their tube burning and testing claims. Their prices are not bad… but you can get cheaper sources… but the burning and matching is very important.
3 - Brands and makers… There has been an open market with entrepreneurs buying brand names and sourcing tubes from different factories… lotsa confusion and mystery out there. I have purchased Svetlana tubes thinking I am just buying a new set of the same, and they flat out were different… same label. Wha???
4 - Tubes really do sound different from vintage to vintage, brand to brand, and maker to maker.
5 - Generally, the best source of information about how a tube will sound in your particular piece of equipment is going to be from the manufacturer or the amp or preamp or whatever. They always are dealing with varying tube supply issues and voicing their products.
6 - Get ready to waste money. It is going to happen. But when you hit on a particular tube you like, it will be all worth it.
7 - ARS - I have purchased most of my stuff from them. I am not sure they are the best for advice, but I have had good luck with them and their prices are reasonable. The guy always has stock. But lately, Upscale has been my go to place for tubes (again, their burn in and testing is what sold me)
8 - Conflicting information abounds… For example, I have a PrimaLuna Diaglog Premium HP integrated amp (from Upscale). I tried and liked JJ/Slovakia KT88 tubes in them (I had a stock of power tubes from prior VTL ownership) but the tube always had some odd high frequency abnormality. No one mentions this about KT88 tubes but I hear it clearly. Upscale tells me they don’t sell JJ tubes because their quality is “awful”. True? I dunno seemed OK to me - I got them from ARS. Related to the sound? I dunno. But overall, the 'net was accurate about the KT88s more power and better bass.
9 - Upscale on driver tubes… Upscale was corresponding with me via email (guy named Jered) and highly recommended two Brimar 12AU7s to compliment my KT88s and bring back that “tubey” sound. Yikes! These two tubes made my ears bleed they were so bright. Jared said I was the first to complain about them. Each tube cost me $95 each. Yikes. $200 thrown out the window. No, I am not knocking Upscale… but get ready to throw some cash away.
10 - Make changes incrementally. Apparently, tube compliments can exacerbate or neuter sound issues. This will drive you nuts. When I am weighing an opinion on the 'net, I totally reject someone’s spew if they order a bunch of tubes and just start making wholesale changes. After a few years of tube rolling, you will have a small inventory of stuff. If you move to more tube equipment, you can start to play with tube compliments and that offers just more entertainment and neurosis. But when you hit it, it is wonderful.
11 - I just ordered eight KT150 power tubes from Upscale… that was about $800 worth… we will see.
12 - I recommend returning your unit back to the stock tube compliment before you stray too far with new tubes. This is a great reference starting point. When you stray too far from stock by changing this out, then that out… you loose your reference point. So, I occasionally return my PrimaLuna back to stock to tubes and remember why I fell in love with this brand. Again, the manufactures voiced their product by trying out different tubes and tube compliments. You can still improve the sound or tune it to your likeing… one reason you can do this is there may be a great tube out there the manufacture knows about but won’t use as stock due to supply issues. Again, talk to your manufacturer.

Good luck. Again, be prepared to throw away money. Do your research but trust your ears. Not all expensive tubes are worth it… the market for tubes is wacky and doesn’t track sound quality. Trust your ears. Trust your ears.

Bruce in Philly


I just picked up a PS Audio BHK250 amplifier from Kevin at Upscale. He added (2) sets of tubes he claims BHK loved. I have about 200hrs on the amp and will change them this fall. I want to make sure the system is broken in and I really understand the sound before I tamper with the tubes.

Kevin Deal:
We found a very special tube made by Tungsram that Bascom King likes a lot. He should. They add a level of texture and sense of space that is incredible. BUT recently I found a small stash of them that are unique. They had been locked up in a warehouse in Serbia for over 50 years. We graded out them by only considering the ones that have the highest transconductance for longest life. Then we look at the measurements and accepted only the ones with a triode balance of 5% or better. We then tested them again, this time for gain, so the two halves of the tube amplify equally and required the same 5% balance. If they pass that test, we put them in a moving coil phono stage with 60dB of gain and listen to them with headphones, carefully listening for both noise and microphony, to achieve the absolute blackest background.

When I installed the super-duper-magic Tungsrams in my BHK pre, I set the current to 5mA per Bascom’s instructions. I found them to add a nice depth and timbre to the bass but they were a bit too crystalline on top—brittle, even after about 100 hours.
Then I set the current down to 4 and it just seemed to take the edge off.

Ron - what are you using for AMP?
I’m using a PS Audio DAC input to BHK250 amplifier (no signal level tailoring); running a Nordost Valhalla 2 HDMI cable from DMP to DAC and Nordost Tyr 2 XLR from DAC to amp and BHK250 has stock tubes and the system sounds great. I’m not hearing any bright treble. These Sonus Faber Guareni Evolution speakers are so smooth at the high end. Even when I really crank them up, there is minimal ear fatigue. As a matter of fact my wife commented on how I like listening to the tunes a lot louder since setting up this system. I’m also using ACS isothermal bass traps (16in and 13in) for the front sound stage w/ diffusers built in. The speakers have outstanding detail, openness, and 3D imaging. I have never heard speakers like these; sure there are better out there… I have owned KEF reference, Vanderstien, B&W… and they are not even in the same zip code as these bookshelf speakers. I believe the speakers are the heart of the 2 channel. The first decision you make building a system is what are your listening priorities. Do you want a forgiving or revealing speakers. Is the music room small, medium, or large and how do I handle the lower 3 octaves. Do I get full range speakers, sub, or bookshelf. Speakers rolling off at 40Hz may be enough when in a smaller room. So, the speakers will dictate sound throughout the bass, mid-range, and treble. I think it is difficult to tailor the preamp to speaker. SF speakers are not the answer, the answer is picking out a set of speakers that you love to listen to and can spend an entire day listening.

So, to answer the initial post - I have a BHK250 amplifier and the treble is amazing, smooth, huge detail, openness… as indicated above. I think it has more to do with selection of speaker, than tubes in the BHK amplifier. I assume you have bought the speakers already and are locked into that sound.

We have a couple of Harbeth owners who post regularly on Paul’s Posts and I have never gotten the impression that they are bright.
So it could be a lot of things, from the room to the cables, and everything in between.
Bruce has given some good advice on tubes. Now if we were talking 6CG7/6FQ7 I would have some experience, I had a preamp that used them. I went a little nuts for a while, buying any brand I came across, other than the GEs. Luckily they were mostly very cheap. I once bought 77 pulled tubes. Cleaned, tested, matched the best I could, and sold most of them to my dealer for a couple of bucks a tube.
I have a CJ CT-5 thst uses 6H30s, as there are only two current brands and the NOS are really expensive, if you can find them, although I think BAT has them for like $300 a tube. Anyway, I have been buying my tubes from Cryoset, and for current model tubes his price is decent, and service is excellent.
You might try reaching out to Badbeef and Steven as they both have Harbeth.

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How do you use a HDMI cable between the DAC and power amp?

Ron - Initially I thought I’d change the tubes once a year; however, I’m listening at least 6 hrs a day and 8-10 hrs a day on weekends. On the weekends I put on Smooth Jazz 101 and listen all day. During the week, I like the SACD and focused TIDAL listening… like Brian Crain for working. I work from home (WiFi) and the system is so amazing and so smooth, I find myself sitting in the music room in the late afternoon with my working laptop doing work till 8:00PM. The ACS isothermal bass traps make such a difference with the tightness of the low end. Room dimensions are 12ft wide, 22ft long, and 10ft high. Since this is a smaller room; I selected a deep bass “book shelf” speaker on stands with very smooth treble.

How often are you changing your tubes and how many hrs a week listening?

Jeffstarr - My apologies, got ahead of myself. HDMI from DMP to DAC, then XLR to BHK250. I just corrected the post, not to mislead others. Thanks for your input.

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