Tube Behavior - ECC823 Thread:

???? This is an ECC82 system combined with an ECC83 system in one enclosure.

Datasheet is here: http://www.mif.pg.gda.pl/homepages/frank/sheets/163/e/ECC832.pdf

Its beavior depends a lot how the 2nd system, the EC82 is used. If V1 is a mixer, this would lead to strange behavior - one channel driven by the 83, th 2nd by the 82.

In typical single channel amps the #82 would usually be the 2nd triode, just because it is on pins 6-8. That would mean:

Input stage unchanged, just a normal '83 stage, sound like JJ/Tesla/Telefunken (same technology). The 2nd one will behave differently: less gain, much wider frequency range toward high frequencies due to reduced Miller effect. In sum roughly like a ECC81, but probably less microphonic and different, cleaner sound than the '81. Maybe more headroom. Depends on the details of the amp.
 
bea said:
???? This is an ECC82 system combined with an ECC83 system in one enclosure.

Datasheet is here: http://www.mif.pg.gda.pl/homepages/frank/sheets/163/e/ECC832.pdf

Its beavior depends a lot how the 2nd system, the EC82 is used. If V1 is a mixer, this would lead to strange behavior - one channel driven by the 83, th 2nd by the 82.

In typical single channel amps the #82 would usually be the 2nd triode, just because it is on pins 6-8. That would mean:

Input stage unchanged, just a normal '83 stage, sound like JJ/Tesla/Telefunken (same technology). The 2nd one will behave differently: less gain, much wider frequency range toward high frequencies due to reduced Miller effect. In sum roughly like a ECC81, but probably less microphonic and different, cleaner sound than the '81. Maybe more headroom. Depends on the details of the amp.
Click to expand...

Thank you for the details, Bea....I'm interested in this tube because I have been told it will roll off the gain in a DSL40C.
 
If the amp uses both triode stages as gain stages - which is usually the case with Hiwatts as a notable exception - this will indeed roll off the gain. In almost any amp.

Simple reason: the '82 system has a gain of around 13.5-17 while the '83 has a gain of around 50-60. So it can be used to reduce the gain in almost any amp, but it is wise to have at least a short look into the schematics before swapping tubes.

The intended use of that tube is in a catodyne/concertina phase inverter: the '82 is really good as a catodyne and the '83 provides its driver stage. Ideally with galvanic coupling.
 
bea said:
If the amp uses both triode stages as gain stages - which is usually the case with Hiwatts as a notable exception - this will indeed roll off the gain. In almost any amp.

Simple reason: the '82 system has a gain of around 13.5-17 while the '83 has a gain of around 50-60. So it can be used to reduce the gain in almost any amp, but it is wise to have at least a short look into the schematics before swapping tubes.

The intended use of that tube is in a catodyne/concertina phase inverter: the '82 is really good as a catodyne and the '83 provides its driver stage. Ideally with galvanic coupling.
Click to expand...

Good points there. Lots of difference in gain!!!!!!!!!!!!!
 
bea said:
If the amp uses both triode stages as gain stages - which is usually the case with Hiwatts as a notable exception - this will indeed roll off the gain. In almost any amp.

Simple reason: the '82 system has a gain of around 13.5-17 while the '83 has a gain of around 50-60. So it can be used to reduce the gain in almost any amp, but it is wise to have at least a short look into the schematics before swapping tubes.

The intended use of that tube is in a catodyne/concertina phase inverter: the '82 is really good as a catodyne and the '83 provides its driver stage. Ideally with galvanic coupling.
Click to expand...

Just to confirm, this is the correct tube, right????

ECC823 - JJ Electronics, Dual Triode
 
Next question:

Of the tubes I currently have on hand, which would be the best choice in the V3 or Power Inverter position???

1. Marshall White Label ECC83 U.K. made

2. JJ-ECC83-MG

3. TAD 7025-WA

4. Marshall Red Label ECC83S

5. 1954 Ken-rad Pewter Plate 12AX7
 
You'll have to try out. A true 7025 should have a little less gain than an ECC83.

And yes, it is electrically safe to replace an ECC83 by an ECC82 and hence also the '832 and '823. The pin layout of the sockets are identical for all 3 tubes and also for the ECC81 and the 12AY7 (which are in between the '82 and the '83).

I just noticed that there are actually two versions: the '832 alias 12DW7 with the '82 system on pins 1,2,3 and the '823 with the '82 system on pins 6,7,8. The latter is unique to JJ and more useful in the design of cathodyne PI stages.

In Your case it depends - with a 12DW7 replacing a ECC83 it is not possible that the 2nd stage will be overdriven, at least in position one, while this is still possible with a ECC823 - the '83 in the first stage can of course also overdrive the input of a '82.
 
bea said:
You'll have to try out. A true 7025 should have a little less gain than an ECC83.

And yes, it is electrically safe to replace an ECC83 by an ECC82 and hence also the '832 and '823. The pin layout of the sockets are identical for all 3 tubes and also for the ECC81 and the 12AY7 (which are in between the '82 and the '83).

I just noticed that there are actually two versions: the '832 alias 12DW7 with the '82 system on pins 1,2,3 and the '823 with the '82 system on pins 6,7,8. The latter is unique to JJ and more useful in the design of cathodyne PI stages.

In Your case it depends - with a 12DW7 replacing a ECC83 it is not possible that the 2nd stage will be overdriven, at least in position one, while this is still possible with a ECC823 - the '83 in the first stage can of course also overdrive the input of a '82.
Click to expand...


Thanks, Bea!!!!
 
Robert Herndon said:
Next question:

Of the tubes I currently have on hand, which would be the best choice in the V3 or Power Inverter position???

1. Marshall White Label ECC83 U.K. made

2. JJ-ECC83-MG

3. TAD 7025-WA

4. Marshall Red Label ECC83S

5. 1954 Ken-rad Pewter Plate 12AX7
Click to expand...

The phase inverter on my DSL15 is V4
In that I used a NOS JAN Phillips 12AT7WC.
A comparatively low gain tube compared to the 12AX7 that was in that spot.
Completely happy with the gain (red) chanel now without affecting the clean (green) chanel. No more fizzy, harsh or rude behavior.
The overdrive is creamy, not over saturated till you dime the gain.
And even then it's still a musical type of distortion. Sustained singing leads without the fizz.

But the ECC823 in V1 alone, is what solved the harshness issue.
 
Using a tube like the ECC81 / 12AT7 in a phase inverter stage is usually a good idea. In my Mywatt i have replaced the ECC83 in this place by a JJ ECC81 or by an old and long used Telefunken (i do not remember, have a few spare ones...), and it sounds great. Well, actually the Hiwatt PI stage had been designed for a ECC81.

HOWEVER (!!!!)

such a swap is not always possible. The ECC82 and '83 support up to 180V between heater and cathode while the '81 supports only 90V. It is known to die quickly when this is exceeded - and cathode potentials above 90V are not uncommon in PI stages. (that's why i'm using an ECC82 in my homebrew amp) So before You swap in the ECC81 as a phase inverter check the cathode voltage!!!
 
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