Excellent choice! I was very impressed indeed when I heard them. Good stands are quite critical, I believe. I could quite happily live with those.
I totally agree. I noticed a massive improvement when I bought a set of sound anchor stands for them.
Hi everyone
I’ve been running my bhk250 for about 1500hrs now and I’m thinking it might be time to roll the tubes.
I am keen to understand views on the following:
-
When is the right time to change tubes? What symptoms start appearing with old tubes?
-
What experiences have people had with different tubes in the 250?
Thanks.
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I have BHK 300’s so similar. I use NOS tubes from yesteryear primarily.
In my order of preference:
Telefunken E88CC
Philips Miniwatt’ 7308
Lorenz 7308
Siemens E88CC
Mullard made RTC E188CC
National Matsushita 6DJ8
I have more but I’m not at home and this is by memory
All of these are good and the differences are more of a personal preference. Right now I have the Lorenz tubes in and I’m amazed at the detail and how “correct” music sounds especially the piano.
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I love tube gear and tube rolling …the frustration comes when as in an
ice cream shop you can’t decide on raspberry, orange. lime sherbets or
chocolate, vaniila or strawberry ice cream…and begin to roll tubes using
the same track to decide on the flavor “of the moment”…
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Hi guys,
Sorry new to the BHK power amp game.
I’ve listened to the BHK 250 with a pair OEM Genalex Gold Lions (stock tubes).
Then, I tried a pair of Tungsram PCC189 tubes. Made the Gold Lions sound very soft and completely flat.
I was very surprised. The Gold Lions had a annoying shrill on some female vocal songs, and was lacking in layering, mid range magic, and bass. Overall, a very flat sounding presentation.
On the other hand, the PCC 189 Tungsrams were rich, detailed, visceral mids, with a beautiful present bass, air on top without the shrill of the Gold Lions.
Now, any further suggestions to try next for continued improvements, if even possible??
Cheers…
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A post was merged into an existing topic: New BHK 600?
Though expensive…but well worth the asking price
nos Telefunken 6922s…these will likely top your
Tungsram and with a much longer service life…
Best wishes
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Have you tried these in the preamp?
PCC189 is a variable mutual conductance tube compare to a PCC88/6922/6DJ8. I wonder if it would translate into an addition of odd harmonics, non linearity, distortion, compression. Maybe BHK can enlighten us here.
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Does anyone know if the BHK amps have adaptive auto bias?
Hay Tubes! From the owners manual:
"The unit is shipped with a pair of hand matched Gold Lion 6922 vacuum tubes, installed in their proper
sockets and ready for use. If you wish to experiment with different tubes, you may use most 6 or 7
Series triode without changing the bias, which is adjusted automatically. Tube rolling, as it is known,
is common practice and an entirely different sound quality can be achieved by changing tube types.
And:
“There are many who will wish to experiment with different tubes on the BHK input in a practice known
as tube rolling. The BHK will accept and work with most 6 or 7 series dual triode tubes. Different
tubes require different bias currents, but *the BHK will automatically adjust the current to exactly what *
is needed.”
HTHs
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I just remembered something if you hadn’t seen it for the pre-amps: Tube rolling a BHK preamp - YouTube
Thanks, BilT. That pretty much answers my question 
. The BHK power amp is fitted with adaptive autobias, similar to my Primaluna pre amp. Wonderful technology really 
.
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The other question I had with BHK power amps, regards their small internal housing for tubes (rear of unit). There is a small rear grill window to allow some ventilation. I notice this compartment gets very hot during normal amp operations. I wonder how much this contributes to shortened tube life (6-12 months), overheating? I note most other tubes amps and even tube pre amps, has the tubes top unit, exposed and well ventilated in the open. Perhaps, Paul could also contribute to this too if possible if there is no clear answer already published somewhere? I realise there are some design constrants from using a P10 or P20 SS bases power regenerator box for a tube/SS hybrid power amp.
Hello again Tubes! I have both Prima Luna and the full PS audio suit. Never had a problem with the tubes from either. Paul recommends changing out the BHK 300s after about a year. But note the NOS tubes will probably last longer. It all depends on how hard you run them. The biggest tube effect is in the preamps, the center 2 for PL and the only 2 for the BHK.
One word of caution: some folks have tried a number of different type tubes that quickly failed. They are mentioned earlier in this thread, I think. Might be in another in this forum, but its here. There’s a lot of great info and collective experience. Enjoy the journey.
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Any idea how these compare to the newly produced Telefunken Black Diamond 6922’s?
Sound wise can’t say as I haven’t hear them…but as far
as quality control…Black Diamonds are made by JJ tubes.
JJ tubes can sound good but longevity is iffy…
NOS Telefunken quality control is unsurpassed
and their sound is superb…if you have the $$$ and NOS
Telefunkens 6922s are available…don’t dilly dally…
just get them!!!
You will be very glad you did…
Best wishes
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I agree with David. Over the years, I have had–and still have many pairs of NOS Telefunken 6 volt tubes and they’ve all been the best sounding and MOST reliable tubes that I’ve owned. Worth the crazy money.
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Considering I can hear the stock BHK tubes starting to decline at around a 1000 hrs, the price for the Telefunken 6922s, which should last much longer, and I’m sure sound better, doesn’t sound all that outrageous.
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