BHKPre not working with 6DJ8’s?

JH, the 7dj8 need to be on the 6v setting-12v is only for the 12au7s… good luck.

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Thank you…

One last question I asked above but didn’t get answered.

Is the bias pin at 5ma when the jumper is on both pins? I assume the pic in the manual is the 4ma setting?

this should be helpful.

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To the orig poster, I used Telefunken 6dj8 in my BHK pre. They are my favorite tube in that application and they work perfectly once voltage and current are correct.

Correct.

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I don’t know where this nonsense about 6DJ8, E88CC’s not working in the BHK PreAmp came from. The amp is designed for them and they work fine. I have used many of these over the years with excellent results. Some can be noisy and those should be disregarded. Not all tubes are equal. Many supposed NOS are actually “Pulls” from old equipment. They may have many hours on them or none. Invest in a Tube Tester and you’re covered. I paid $150 Canadian for my B&K Dyna 606 and it’s like new and has saved my butt many times. My favorites after 3 years with the BHK Preamp are the Telefunken 6DJ8’s.

Why doesn’t the same occur with NOS 12AU7 tubes (as much as of course there are bad 12v tubes)? The 6v tubes demand more current.

Simple, the 12au7 is inherently a much better and tighter spec’ed tube than a 6dj8. That’s why you see it in great $10k pre’s and phono pre’s.

Whenever I mention 6dj8s to amp repairmen and amp designers, curse words fly out of their mouths. They are way too hit and miss. And the quality runs the gamut. I am sure that’s what led to having to develop 6922 and 7308s. I have 30 years with that tube and I have seen pre’s that simply will not turn on with them, but they test fine. I spend more time on a Hickok 539b testing, matching 6dj8/7308s than any other tube. Why do you think ARC and Sonic Frontiers used Sovtek 6922 in the 1990s? They sounded MEH but were tightly spec’ed and internally matched. They worked and lasted forever.

There are a ton of great nos 12au7s out there, even some new ones are OK. And you can concentrate on sound, not whether if the amp will turn on.

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hey man, it is a surprise to me but when i got a set from Brent Jesse tubes, they were not at all compatible being very noisy and hissy. hard to figure as they should have worked. from his web site

7DJ8 / PCC88:

This is an unusual tube that must have had a limited range of specific uses. It is virtually identical to the 6DJ8 except for the heater rating, which is 7 volts

Kevin Deal has always recommended the Tungsram 7dj8 as their preferred tube for the preamp

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Hi mate

Once I changed the voltage they were fine and not noisy. I just found them a little more brittle than the gold lions I usually use. However, I like warmer sounding equipment so maybe just not for me. Was worth a try.

Thanks.

these look very promising and are not that expensive.

I have been having a lot of trouble with MATSUSHITA / NATIONAL PCC88 / 7DJ8. They sound great except for the popping and clicking with the volume control.

thanks. never tried them but they are (or were) possibilities. i have had good luck with the Tungsram 7DJ8 from Upscale but they are no longer available.

The Matsushita’s are a great sounding tube in the amps but I found them to be a no go in the preamp also but to me it was hiss level. No popping or clicking when running full balanced but SE is another story.

The Matsushita 7dj8’s were absolutely silent and sounded great in my BHK preamp. Go figure.

The Matsushita 7dj8’s are a hidden gem! Was my #1 tube in my Sony HapZ-1es. Very nice in my BHK… silent in both!

Rolled Matsushita’s in the BHK pre with no noise issues…dead silent. Racked up 258 hours before changing them out. Very detailed and solid bass. I ordered a second set, just because. Currently rolling through NOS RT, Mullard, and RCA 12AU7’s.

…edited hours, 131 was incorrect and for the RT’s.

I am fully balanced, running the Matsushita’s in the BHK pre. Volume pops in one channel with this set, but no hiss or pulsing, which I did experience with the previous set of same.

Are there any really outstanding 12v tubes for the BHK?

I’m pretty sure I’ve found one in the list above. It’s pricey, but not un-obtanium, and I’m contemplating picking up 2 more sets for my stash. Have a few more weeks of rolling before I decide to commit. Will reveal details of my pick after I’ve secured backups.

Should also add I’m fully balanced, too.

For 12AU7’s there are still vendors with quality matched pairs of NOS tubes if that is what you want or a safe and reasonably good sounding current tube are the Gold Lions. There is a vendor on Ebay myself and others have both from that has some good NOS tubes but you need to buy the Platinum Plus pairs for the BHK. Doesn’t require spending the money asked for Telefunkens either. For a B&M dealer call Andy at Vintage Tube Services on the phone as he doesn’t like to do business via e-mail.

Here’s a link for the Ebay seller

https://www.ebay.com/sch/spin4cards/m.html?_nkw=&_armrs=1&_ipg=&_from=

This is a good sounding tube in the BHK