is 7DJ8 a real substitute for 6DJ8???

[Daddy Dee]

The text below is from Brent Jesse's website. He makes a good case, but also uses the word "probably" describing the possible sub. Any folks familiar with the tube specs and what they would mean in a real world substitution... your take is appreciated. If it is, it's a good bang for the buck consideration.

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. I have seen Siemens, Valvo, Telefunken, Philips, Ultron and Matsu****a (Japan) brands of this tube. It probably makes a good sub for the 6DJ8 and may last longer due to the higher voltage heater. Some are labelled with only the "PCC88" and others have both types listed on the label. All seem to be good quality. The Japanese factory was set up by Mullard, and these tubes even flash orange at the bottom of the filaments when first energized, like most European triodes do. Most of the European types were made at the Munich Siemens factory, the Hamburg Valvo factory, the Heerlen Holland Amperex Factory, or the Blackburn, UK Mullard factory. These sound just like the best 6DJ8 tubes, the German tubes being mostly neutral, and the Dutch and British tubes having a touch of midrange warmth. You may want to try a 7DJ8 for the longer heater life in a 6.3 volt circuit, and the lower price!

edit: if this thing is a real winner, I'll thank you in advance for NOT buying up Brent Jesse's stock before I have a chance to order.

[Daddy Dee]

Thanks Mark,

That is an interesting question as to what the real world trade off would be in terms of added distortion.

[doctorcilantro]

I'm real interested in trying these out in my Sunfire moving coil stage. I have heard they do sound great even when undervolted, but on AA some were discussing they could sound even better at 7v. This is a high gain situtation which I was considering upping further to 65 or 70db. I'll report back after testing these. Sunfire couldn't give me any info over the phone as to the rated voltage (6.3?) for the Classic Tube Pre which uses (4) 6922/6DJ8 (one for "Infrasonic filter) and it also uses the two 12ax7s from the MM stage.

DC

[mark1101]

What would be great is if someone would make a really extreme sounding current product 6922 for a reasonable price. The 6922 is one tube I have been burnt on for trying to purchase NOS. I quit buying most of the so-called NOS ones. Most were not brand new and most were noisey. You buy the current production ones and they can't hold a candle to the sound of the really good old ones. Frustrating. I found the EH 6922 Gold pin to be the least offensive as far as noise but it does not sound near as nice as an old Telefunken or Bugle Boy. Jan Philips 6992 is a bargain NOS tube from the 80s if you can find a quiet one. They sound good in a Peach.

[doctorcilantro]

I have some Amperex (various makes) 6922 and I keep them in the line stage. Now that I'm using the moving coil I need some good tubes. I tried some of my Amperex in there and while super microphonic (booming to the point of an echo when I rapped the preamp housing) they sound was so much better with them than these EH 6922. I am going to do some heavy listening with Amperex, EH, and Sovtek in the Mc this weekend. I swear there was a major differece; I need to make sure my tonearm/tracking force didn't get out of alignment.

I'm looking at Tesla 7DJ8 w/ low noise and matched right now but tempted to buy some Telefunken 7DJ8/PCC88 for less than half the price of the Tele E88CC. I found some info on AA about the 7DJ8, all quite positive, especially the Tesla...for the price might make sense.

DC

[thebes]

Dee, why not try before you buy?

I have a pair of (matched if I recall correctly) Lorenz PCC88's in da house which I'd be happy to lend to you for a listen. They were real NOS when purchased late last sumnmer for $45 and still have very low hours on them. I do believe I recall that one was slightly noisy in my Anthem pre on the low gain phono stage setting but ok when placed into my AH '99 cd player.

Even if one turns out to be slightly noisy in your pre it would probably still give you a feeling for the sonic charachter of these tubes. PM me or email your address. I'm leaving for a week tomorrow and may not be able to get them out until I return./

[thebes]

Dee, why not try before you buy?

I have a pair of (matched if I recall correctly) Lorenz PCC88's in da house which I'd be happy to lend to you for a listen. They were real NOS when purchased late last sumnmer for $45 and still have very low hours on them. I do believe I recall that one was slightly noisy in my Anthem pre on the low gain phono stage setting but ok when placed into my AH '99 cd player.

Even if one turns out to be slightly noisy in your pre it would probably still give you a feeling for the sonic charachter of these tubes. PM me or email your address. I'm leaving for a week tomorrow and may not be able to get them out until I return./

[thebes]

Dee, why not try before you buy?

I have a pair of (matched if I recall correctly) Lorenz PCC88's in da house which I'd be happy to lend to you for a listen. They were real NOS when purchased late last sumnmer for $45 and still have very low hours on them. I do believe I recall that one was slightly noisy in my Anthem pre on the low gain phono stage setting but ok when placed into my AH '99 cd player.

Even if one turns out to be slightly noisy in your pre it would probably still give you a feeling for the sonic charachter of these tubes. PM me or email your address. I'm leaving for a week tomorrow and may not be able to get them out until I return./