305 tube rollin

had a bit of free time last night....
what to do, what to do....
how about playing with my tube's....

started diggin into what I have, and found a set of Harman Kardon 12AT7's (German), to replace the current ones that came with the amps, a set of ???, as these only say 12AT7WA
made in the USA.

the only real change that the HK tube did was bring the sound stage a bit more to the center, with the originals it was a bit wider.
not that stock tube sounded bad. the HK's brought it just a bit more to the center, tighter if you will.
as to the sound, I did not really hear any change, the lows, mids and highs all sounded the same.
kinda nice to know this, as this takes one tube out of the loop....

onto the 12ax7's, which I do have a few different types.....

more to follow............

okay, stock 12ax7 was JJ's now it is a set of HK's (British)
while the jj's sound real good for cheap tubes the hk's have a better air about, them a bit cleaner also, didn't even try a set of sovtek's, but may just for the fun of it.....


time to turn the fridge back on, noisey piece o crap....
going to make a timer/contractor so when I forget to turn it back on I will not rune my milk....

Tube rolling is always fun. Glad to hear you are having fun. I ender who makes the HK tubes you have. Do they have a diamond on the bottom? They might be Telefunken. Time for Chauss to pop up he might know.

yes the at7 have a diamond, so my guess is the ax7 might be mullards.
tried to find info on them and found none.

put the sovteks in, uuummm, NO
noisy....

yes the at7 have a diamond, so my guess is the ax7 might be mullards.
tried to find info on them and found none.

put the sovteks in, uuummm, NO
noisy....

Sovteks, imho suck.

One of these days I'll get around to some more tube rolling. Brian reccommended the PSvanes, anyone try them yet?

One of these days I'll get around to some more tube rolling. Brian reccommended the PSvanes, anyone try them yet?

Yes Robin, you are correct I really did like the Psvanes I used the 12AT7 and the 12AX7 in the Cherry's
along with the KT-120's the bottom end was fantastic.
I thought they worked better than the Telefunken 12AX7 (that you now own)

Brian

I am still running the KT-120's. However, the entire front end is now Telefunken. That made a huge difference.

Until I can score 12 treasures, I am going with Valve Art KT-88's (Shuguang) I have heard they sound very nice.

I am also going for the look. lol

yes the at7 have a diamond, so my guess is the ax7 might be mullards.
tried to find info on them and found none.

put the sovteks in, uuummm, NO
noisy....

Mike,
If the AT7's have a raised <> on the btm between the pins- they are Telefunkens--they produce a very wide and transparent soundstage- one of my favorites!
If your AX7's are Mullards you will really enjoy them with guitar music, especially acoustic guitar. AT7's have a bit less gain than the AX7's so you may not hear as much goodness from the TFN's as compared to what they can muster in a 12AX7 flavor- should still sound sw-e-e-t though!

Please post your thoughts after listening for a while! Every system seems to play tubes just a bit differently.

Tried the Pavave 12at7 and 12ax7 and found them to sound the best overall. The Power tubes are the KT120's. I also tried the Mullard 4004's & 4024's in them and the midrange is something niiice...but after all is said and done, I end up back with the Pavanes back in my system.

Can you substitute 12at7's for 12ax7's in the cherry 180's?
Meaning having a total of four 12ax7's running in a pair of 180's.
What might be the pros and/or cons?

Until I can score 12 treasures, I am going with Valve Art KT-88's (Shuguang) I have heard they sound very nice.

I am also going for the look. lol

Tom.

I have a few (8/10) Treasures that I am not using, I will bring them to CF12, make sure you bring your tube tested and
we will work a deal out.

Brian

Can you substitute 12at7's for 12ax7's in the cherry 180's?
Equalling a total of four 12ax7's running in a pair of 180's.
What might be the pros and/or cons be?


Somebody...Anybody

Tried the Pavave 12at7 and 12ax7 and found them to sound the best overall. The Power tubes are the KT120's. I also tried the Mullard 4004's & 4024's in them and the midrange is something niiice...but after all is said and done, I end up back with the Pavanes back in my system.

If you only tried the CV4024's, you absolutely have to try the CV4024/M8162's as they are in a completely different league.

Can you substitute 12at7's for 12ax7's in the cherry 180's?
Equalling a total of four 12ax7's running in a pair of 180's.
What might be the pros and/or cons be?

this is a ? for Bob, this can be asked at CF.....


was thinking about this and found some info...


In general, 12AX7 tubes are selected where high open loop gain is necessary, 12AT7 tubes where higher output current drive is more important than high voltage gain.

this is also what came to me as I was at work.....
thinking about other things than my job...

http://www.audiocircle.com/index.php?topic=98231.0

Good question. A general comment. The 12AT7 family has approximately 3.5 times the transconductance of a 12AX7 family. Subbing a 12AX7 for a 12AT7 will mean only 1/3-1/4 the plate current, so idle plate voltage will be much higher than with a 12AT7. Two questions emerge.

1) In an amplifier, is there enough signal voltage swing capability to drive the output tube to full power before maximum plate voltage swing reaches B+, and "flat tops".

2) As the plate current drops closer to zero, the curves become more nonlinear. More distortion.

So no matter what the circuit, conditions won't be optimal.



http://www.cydathria.com/fdm/12AX7_sub.html

Tried the Pavave 12at7 and 12ax7 and found them to sound the best overall. The Power tubes are the KT120's. I also tried the Mullard 4004's & 4024's in them and the midrange is something niiice...but after all is said and done, I end up back with the Pavanes back in my system.

If you only tried the CV4024's, you absolutely have to try the CV4024/M8162's as they are in a completely different league.

What have you experienced with the Mullard 4024/M8162's compared to the reg Mullard 4024?
With the 4024 or 4024/M8162 situated in the driver stage, have you found it to dramatically change the overall sound of the Cherries? I was under the impression that the Input Stage (12ax7 or 4004) was the primary force in altering the sound of an amp. I am new to this tube thing, but this is what was passed on to me

Ranking in importance in the alteration of the sound of a tube amp
1) input stage tube(s)
2) output tube(s)
3) grid or driver tube(s)



I tried to contact Bob about the substitution of the 12at7 for a 12ax7, but I haven't heard back from him. I gathered he's busy and all.

Can you substitute 12at7's for 12ax7's in the cherry 180's?
Equalling a total of four 12ax7's running in a pair of 180's.
What might be the pros and/or cons be?


Somebody...Anybody

although it was anwsered, bob said a few months back when i asked, the current capacity in the tubes are different and that is why you have both. so no it would not be a good idea, or bob would have done it from the start. as a side note, i am looking forward to using the psauve tubes i ordered.