• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

What 2a3 ?

I want to buy a pair of 2a3 for my Tubelab SE amp.

I found locally the following choices:
1) NOS JJ 2A3-40 $320
2) Sovtek $75
3) Golden Dragon Premium $160
4) EH $110
5) Tronal $190

Then there are also Full Music and KR, but far more expensive.

What do you recommend ?

Thanks,

Davide
 

45

Member
2008-12-18 2:29 am
UK
I want to buy a pair of 2a3 for my Tubelab SE amp.

I found locally the following choices:
1) NOS JJ 2A3-40 $320
2) Sovtek $75
3) Golden Dragon Premium $160
4) EH $110
5) Tronal $190

Then there are also Full Music and KR, but far more expensive.

What do you recommend ?

Thanks,

Davide

The JJ is a 300B with 2.5V filament supply.
Also the Sovetk, EH and GD premium with that single plate don't measure exactly like a 2A3.

I would go for the normal Golden Dragon (double plate) that is a true and very good 2A3. It has also got a gold grid. You just need a good selection for mutual conductance because it can vary quite a bit, from approx. 4.2 to 5.2 mA/V typically. Actually this was and is true also for NOS tubes....
As vintage option there is the Russian 6C4C. This is very good as well but requires a DC filament supply. It is an improved copy of the RCA design, IMHO. This has the advantage of higher maximum rating for plate voltage (360V instead of 300V).

45
 

costis_n

Member
2008-08-01 1:18 am
NOS JJ ??? Since when? JJ has been around for how long (as a label, I know it was Tesla before)? 8 years? New Old Stock is a ridiculous buzzword. I guess "Sitting on the shelf for 5 years" doesn't sound nearly as cool....

On the other hand, I have recently stumbled upon an electronic parts shop that has loads of Mullard "mustard" caps. Anybody interested?
 

CLS

Member
2005-06-17 6:58 am
Taiwan
A fan of the jj 2a3's - using them vs eh2a3 was quite significant (in a couple of amps). Less glare in the treble and better bass with the jj's.

If not compared directly, the HF 'glare' of EH2A3 is that bad?

I'm using EH2A3 now, not feeling its glaring treble. Compared to my previous 6S45 spud, it's slightly brighter in HF, but not to the degree of 'glare'. And I guess it can be largely affected by other factors, like power supplies, OPT, driver circuit... etc., other than the output tube itself...

Interestingly, its mid to lower mid is also richer, fuller, with more punch and strength. So overall a more energetic and blooming sound, not thin or clinical at all. I like it a lot.

Oh well, that's not even a 2A3 comparison:eek: I've only used EH by now. And it serves 240Hz and up, so I don't know it's bass performance.
 
Thank you very much for the advices. Reading around I realize that NOS JJ sounds silly. I will check in the shop, maybe they are Tesla. Anyway it looks like they are mainly 300B with 2.5 V Filament. I already have a pair of 300B, so maybe there is not much point, as the goal is to try something else. I am running the amp with the 45 now, but the OPT can handle the current of the 2a3 as well.

Thanks,

Davide
 

costis_n

Member
2008-08-01 1:18 am
Thank you very much for the advices. Reading around I realize that NOS JJ sounds silly. I will check in the shop, maybe they are Tesla. Anyway it looks like they are mainly 300B with 2.5 V Filament. I already have a pair of 300B, so maybe there is not much point, as the goal is to try something else. I am running the amp with the 45 now, but the OPT can handle the current of the 2a3 as well.

Thanks,

Davide

Yes, I read somewhere else that they are 300B's. They are just keeping their costs down.
 
other than the output tube itself...
When comparing output tubes only, B+ voltage and bias should be checked to see how much of discrepancies there are between them. One can change the way tube amp sounds without switching output tubes. Just tinker with those two parameters. So many online reviews about OPT don't mention such things. :rolleyes: Take them with a grain of salt.
 
When comparing output tubes only, B+ voltage and bias should be checked to see how much of discrepancies there are between them. One can change the way tube amp sounds without switching output tubes. Just tinker with those two parameters. So many online reviews about OPT don't mention such things. :rolleyes: Take them with a grain of salt.

This is what I always think when I read about the "sound of the rectifier": changing rectifier you modify the B+ and the impedance of the PSU, no wonder that the amp sound different.

D.