Alas after no pulsing for two days it returned last night now in both channels so I’m going to call them. Maybe the pulsing is with the premium cryo tubes only.
If it helps, I did not order my Tungsrams from Upscale, and I have had zero issues – go figure…
Thanks, would you tell me from where ? I assume they are NOS, are they cryo’ed ?
The Tube Store (www.thetubestore.com). The tubes are not cryo’d, but the triodes are matched and balanced.
I should also note that I owned a Cary preamp, and continue to own CJ power amps. So, I’ve used The Tube Store quite often, and for many years.
I have a question for the tube rollers: I read through BHK’s posts and all the discussion around the development of the Preamp. Great info [and thanks very much for your time and work @bhk ]. I found especially interesting the decision to settle on the 12AU7 tube for production, even while favoring the 6922 and certain NOS 7DJ8 tubes for their sonics. I have ordered several sets of the recommended Tungsrams from both Upscale & The Tube Store, and am looking forward to those, but I have a couple of questions for the group:
The 12AU7 came up as a matter of curiosity if I remember correctly. I looked at the general 12–7 group of tubes and the closest one with the closest gain and shape of the characteristic curves with the operating plate voltage supply to the 6922 genre was the 12AU7. I tested it in my tube circuit setup and with the current reduced from 5 mA to 4 mA the measured performance was similar to the 6922 types. This was promising. Then my good friend and associate Arnie Nudell ordered a bunch of different brands of 12AU7 tubes that were currently manufactured. Of the ones he tested by listening to them, the Psvane one sounted the best and was very close to the sound of the Tungsram 7DJ8 that we favored.
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I am curious as to why there seems to be less reported tube rolling past the Tungsram tubes that BHK favored. There are some nice candidates out there e.g., Telefunken, Phillips, Ediswann. Is this a case of heeding the designer, as well as the relatively short period of time we’ve had to try out alternatives?
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I am also wondering why so little love for some of the very fine 12AU7 out there? I realize that in the high end market, 6922 has the reputation of being more desirable, but is it inherently so in this design? I have some nice 1960s Mullard NOS 12AU7 that I am going to have to try. As @lonson knows, I was about to simply give all my tubes away, but I see now that I need to sift through them first.
I swore I would put tube rolling behind me, but here I am again. Ah well. Ah well, do try some of what you have and let us know what you find!
Ah nuts, the color didn’t come out in what I had added.
If you ordered NOS 7DJ8’s from Upscale hope yours work out better than mine, finally returned them because of the pulsing.
I read about those issues; sorry to hear you had all those problems. Did Kevin share any assessment about the source of the problem? I ordered from both Upscale and TTS. Will see how they work out.
No I was surprised he gave me a bit of a hard time at first implying what I was hearing was not possible and that no one else had complained about this, (ref Mark’s earlier comment), finally backed off and offered a refund.
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I can understand his reaction. It is a truly bizarre story.
I couldn’t because it was near hostile at first.
I suspect he gets jerked around a lot.
He is completely legit. Not all of his customers are.
And your issue has been addressed as you desired.
palerider said I have a question for the tube rollers: I read through BHK's posts and all the discussion around the development of the Preamp. Great info [and thanks very much for your time and work @bhk ]. I found especially interesting the decision to settle on the 12AU7 tube for production, even while favoring the 6922 and certain NOS 7DJ8 tubes for their sonics. I have ordered several sets of the recommended Tungsrams from both Upscale & The Tube Store, and am looking forward to those, but I have a couple of questions for the group:Somehow my additions in color don't come through. Second paragraph and the addition to the last sentence.The 12AU7 came up as a matter of curiosity if I remember correctly. I looked at the general 12–7 group of tubes and the closest one with the closest gain and shape of the characteristic curves with the operating plate voltage supply to the 6922 genre was the 12AU7. I tested it in my tube circuit setup and with the current reduced from 5 mA to 4 mA the measured performance was similar to the 6922 types. This was promising. Then my good friend and associate Arnie Nudell ordered a bunch of different brands of 12AU7 tubes that were currently manufactured. Of the ones he tested by listening to them, the Psvane one sounted the best and was very close to the sound of the Tungsram 7DJ8 that we favored.
I am curious as to why there seems to be less reported tube rolling past the Tungsram tubes that BHK favored. There are some nice candidates out there e.g., Telefunken, Phillips, Ediswann. Is this a case of heeding the designer, as well as the relatively short period of time we’ve had to try out alternatives?
I am also wondering why so little love for some of the very fine 12AU7 out there? I realize that in the high end market, 6922 has the reputation of being more desirable, but is it inherently so in this design? I have some nice 1960s Mullard NOS 12AU7 that I am going to have to try. As @lonson knows, I was about to simply give all my tubes away, but I see now that I need to sift through them first.
I swore I would put tube rolling behind me, but here I am again. Ah well. Ah well, do try some of what you have and let us know what you find!
BHK
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Thanks Bascom, I appreciate that reply. Rollin’, rollin’, rollin’…
rogerdn said I couldn't because it was near hostile at first.Kevin wasn't hostile w/ me - but after the second tube he asked me some pretty thorough questions regarding my troubleshooting process. Kevin's response was that historically these tubes were very stable if they tested ok. In the end he replaced both suspect tubes - I have no complaints.
OTOH, after the second set of Upscale Audio tubes started pulsing I pulled them and put a set of Tubestore Tungsram 7DJ8 matched tubes in. The first thing I noticed was that volume changes on the BHK were now silent(w/ the Upscale tubes I heard clicks and noise). Overall musicality seems to be better also. YMMV.
An odd problem to experience. Did he offer an hypothesis as to what is going on?
Mark said OTOH, after the second set of Upscale Audio tubes started pulsing I pulled them and put a set of Tubestore Tungsram 7DJ8 matched tubes in. The first thing I noticed was that volume changes on the BHK were now silent(w/ the Upscale tubes I heard clicks and noise).That's interesting (and strange). I don't recall a difference in the volume change clicks when I replaced the stock tubes with the Tungsrams, but they became less noticeable when I went from RCA to XLR interconnects between the pre and BHK 250 amp.
Elk said An odd problem to experience. Did he offer an hypothesis as to what is going on?No, he was not happy that I was having problems with tubes that tested fine on his end and I was not happy having tubes that degraded in sound quality after a few hundred hours. After replacing the Upscale Audio tubes with the Tubestore tubes and having the audible clicks that I heard on volume changes w/ the Upscale Audio tubes go away I'm scratching my head. FWIW, when using the stock 12AU7 tubes I did not hear the clicks when changing the volume.
Hi Bascom,
When you voiced the variety of tubes for the preamp, did you try any of the other more expensive 6922 or 12AU7-type NOS tubes, such as the Telefunken, Siemens, Amperex, or others?
While the Tungsram really does make the amp sing as you note, I’d like to roll others as well. That being said, I don’t want to spend 200+ on a pair of NOS if you had already tried that particular make and had decided that it didn’t sound as good as the Tungsram.
Hope that makes sense, and appreciate your insight when you have a chance to provide…
+1. Would be interesting to know some of the other tube comparison points. The Telefunken continue to perform well in my setup, but I am wondering if I am hearing some mid-range, especially vocal, forwardness. May have to swap tubes a few times to see.
If it helps other BHK Sig owners widen their tube rolling choices, I’ve been listening to both NOS Telefunken (E88CC, 1960s production) and NOS Siemens 7308 (E188CC, 1960s and early 1970s production). With the high bias jumper setting. I’m a huge fan of the NOS Telefunken 6922, but for my money the Siemens 7308s elevate my BHK Sig to another level. Incredible bass drive and extension that excels even the mighty Telefunkens with midrange to die for. I listen to a lot of voice and jazz and these 7308s are blockbuster tubes for that kind of material. Yes they’re pricey and hard to find, but I’m so sold on 7308s for my BHK Pre I’ve invested in a backup pair.
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