• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Tubes in your system?

Kegger said:
Very cool looking little unit yu got there!
Click to expand...

My wife tells me that from time to time. :D

I have a quick tube question (probably a dumb one). Will NOS RCA 7591A tubes be plug and play for a Fisher that has 7591s. I remember hearing something about the "A". It looks ok to me in the RCA manual, but just thought I'd ask to be safe rather than sorry. Thanks, Jay
 
Well, I've got another question that I can't seem to find a definative answer to. :no: Would a 6922 (or 6DJ8) be plug and play for a 6N1P? If not, what would be a good tube (or tubes) to try in the 6N1P stage of a SE300B amp? From my research it appears that the 6N1P is a Russian made tube, and I was wanting to try some good ol' USA tubes up front. Thanks for any and all advice, Jay
 
Double check the voltage at the plate of the tube, if it's 130 or less then a 6dj8 should
be just fine and if it's 200 or less a 6922 should be fine. (Give or take as some handle more)
But more then likely no problem with the sub. :thmbsp:

It's when you go the other way around, subbing a 6n1p for a 6dj8/6922 where you can
run into trouble as the 6n1p draws more current.
 
Thanks Kegger, That was what my data was showing, but I don't completely trust my interpertation just yet. It's nice to have another opinion :thmbsp:
 
6fw8 and 6es8 are 2 other possable candidates.

Quite a few different ECC's and CV's as well to. If you rewire a few pins of the
socket you'll open up a whole nother world of tubes to roll/try!

What your really looking for is, (As for drop in replacement)
The pinout (9AJ), plate resistance (I'd say 2200-3000), and gain (say 25 to 40)
If a tube meets all those then look at the voltage and current of the one yu suspect.
(Others close to these specs may work as well depending on the circuit)

You may be able to get away with one that has a higher plate resistance depending
on the load that's applied to it, many believe a 5x plate resistance to the load value.
So if you normally run 6n1p,6dj8,6922 that would mean 5x say 2650 which is 13.25K
If your plate load is 15k or less I would stick to the tubes with a 3k and under plate R.

These are just some general rules and don't apply to all but it's a good starting point. IMHO
 
Kegger, You have a way of explaining things, that makes the little dim bulb in my head light up. :D I got these monos to use in the man cave, so there will be lots of rolling and experimenting. I'm still struggling with some basics, but I'm still reading every night and asking questions here, so someday......... BTW what is pin 9 on the 6DJ8 type tubes? On the pinout it is a dotted line seperating the triode sections :scratch2: Thanks, Jay
 
Kegger said:
Very cool looking little unit yu got there!
Click to expand...

Thanks Kegger, its a nice sounding little amp. I've noticed the transformers get pretty hot I just hope it holds up over time. Seems to be well-made.
 
"BTW what is pin 9 on the 6DJ8 type tubes?".... Basically it's a no connection.

That's the difference between that pinout and the types like 12au7, 12ax7. (9A)
What they do is pin 9 with pins 4,5 tied together to use 6.3 but use just 4,5 for 12volt.
That's why those tubes have a 12.6 and 6.3 heater rating where a 6DJ8 is strictly a 6.3.

And Jay yes I am still learning every day as well! :yes:

----------------------------------------------
Donoghue glad the little amp sounds as cool as it looks,
yes the trannies should get pretty hot.
 
This thread may live forever :D I've got just a couple questions. First do any of you guys who use tubes in the 6DJ8 family have any suggestions as far as a tube that may give the bass a shot in the arm? I'm finding out that some of these rascals are pretty high dollar, so I thought maybe I could save some dough by asking around. I was looking at some Mullards, but crap, they seem to be selling for 75 plus per pair. :drool: The only thing I've tried so far is 6922 Phillips JANs which are fine in the mid and upperHz, but a bit wimpy down low. The Russian 6N1Ps that were in the amps made better bass, but the higher stuff was grainy. On a different subject, does anyone know anything about Japanese made AWA-Thorn tubes? I'm trying to keep a Japanese amp, all Japanese and one of the Matsushita 6BM8s is gone. I heard somewhere that Awa-Thorns were made by Matsushita, but don't know for sure. They seem to be plentiful, where as Matsus are not. Thanks in advance for any ideas, Jay
 
If you can locate Sylvania (Gold Brand) EXPORT (made in France) 6DJ8, you may want to give them a try. They are rebrand Amp's that sound, look and taste just like the high priced spread. I found mine via EBay. Made 5/74 and were less than $10 per. Good Hunting.
 
jaymanaa said:
This thread may live forever :D I've got just a couple questions. First do any of you guys who use tubes in the 6DJ8 family have any suggestions as far as a tube that may give the bass a shot in the arm?
Click to expand...

For bass, the new-production JJ's are pretty ridiculous in my Juicymusic Peach ... moreso than most of my old stock tubes ... and they sound close to "neutral". Of course, much will depend on the actual operating point in your amp. Russian 6N23Ps aren't too shabby either, but can get a bit glassy up top.
 
Those all sound good :thmbsp: I was trackin some fancy ones on ebay, but I'll be danged if I'm gonna pay 100 bux apeice for small signal tubes :no:
 
jaymanaa said:
Those all sound good :thmbsp: I was trackin some fancy ones on ebay, but I'll be danged if I'm gonna pay 100 bux apeice for small signal tubes :no:
Click to expand...

Hey Jay,
I didn't find a whole lot of magic in the 6DJ8. I prefer the 6BQ7, ironically the older black plate/white printing RCA variety sounds the best where I use it. Fortunately there are other varieties that also sound good, and these are $2 tubes....:) GE 6BK7B is also a nice one.
cheers,
Douglas
 
Still tweaking lots but I have finally come up with some winners....
Amplifier--2- Brimar CV4004 12ax7's in my amp( Nos valves built) as well as 2- Mullard CV4003...very very nice!! Have some Valve Art KT88's in there "for now".......
Pre Amplifier ( Bottlehead Foreplay lll) In there I have the same Mullard CV4003, Had some EI's as well as some RCA black plates in there but the Mullards took em to school IMHO....
Phone Pre (Bottlehead Seduction) have some Reflektor ( Russian Military) in there and love em..... Had Phillips which were horrid and some Ei's, not bad but like the Reflektors better, seem to be tighter cleaner and more separation IMHO!!!
 
pocketchange said:
Maybe a listing of the 6DJ8 family would be in order with the sonic's included.
Or would there be a thread covering this subject?
Click to expand...

Hey!!!,
That's one of the more difficult things to do. First...it's opinion based for the most part. Second, a large part of the sound is due to the relationship with the rest of the amp, load, OP, PS design...all contribute. It is a bit difficult to seperate them. With a host of different equipment, it would be possible to get some insight.

Look for general trends and shared characteristics in the tubes operated in a lot of different ways. The simpler and usual way has always been to try rolling the various valves into a single bit of gear and see how it sounds. Useful, but conclusions are extracted from a small data set IMO...:)
cheers,
Douglas
 
Like Douglas says there will be differences in different circuits but the general sounds
of particular brands will still try and hold true, meaning a tellie will still have the tellie
sound which is a tip toward better performance on the highs and a mullard will still be
a mullard with at least retaining a touch of it'self within most circuits and that's where
they tend to shine in the midrange on down area.

Now if you mean different types of 6DJ8's well there really is only 2, 6DJ8 and 6922 if
you are wanting to stay with the same pinout and plate resistance while keeping the
same internal structure as well. The other one is the 6FW8 which is the same frame-grid
type of tube that has the same numbers as the 6DJ8 and I would tend to label them as
a tad not quite as sharp sounding as the typical 6dj8/6922's, smoother if you will.
(But everything is circuit dependant)
 
Thanks Kegger, you covered my Q's with your last paragraph. I haven't needed any new 6DJ8/6922 examples in a long time and I just wasn't up to speed on the other #'s
being mentioned. Early Amperex examples make my setup sing.
 
You must log in or register to reply here.
Back
Top Bottom