Hello All,
For a long long time NOS tubes like the 12ax7 prices had gone through the roof yet the use of NOS compactrons, some can perform the same function is relatively low.
New amps can be constructed and perform very good using them.
Any idea why?
BR
Glass_painter
For a long long time NOS tubes like the 12ax7 prices had gone through the roof yet the use of NOS compactrons, some can perform the same function is relatively low.
New amps can be constructed and perform very good using them.
Any idea why?
BR
Glass_painter
NOS tubes do not present a large, open, and stable supply chain for commercial scale. Obviously nothing stops using compactrons for hobby scale.
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Glass_painter,
Go to Eurotubes.com
The only sell the latest production of JJ tubes.
They Extensively Re-Test the characteristics of all the JJ tubes that they sell (including testing for Noise).
Order a pair of JJ ECC83 tubes from Eurotubes. (12AX7)
They use Spiral Wound Filaments.
They do Not use the more common up, down, up, down . . . filaments.
When you get them and try them, you will be a happy person.
Expensive to ship to Israel?
Good things do not come Cheap.
Cheap things do not come Good.
Happy Listening!
A "Compactron" is not very compact. It takes up much more real estate than a 12AX7.
And it likely has more sections in it that take up much more filament power than a 12AX7.
Just my opinion.
Go to Eurotubes.com
The only sell the latest production of JJ tubes.
They Extensively Re-Test the characteristics of all the JJ tubes that they sell (including testing for Noise).
Order a pair of JJ ECC83 tubes from Eurotubes. (12AX7)
They use Spiral Wound Filaments.
They do Not use the more common up, down, up, down . . . filaments.
When you get them and try them, you will be a happy person.
Expensive to ship to Israel?
Good things do not come Cheap.
Cheap things do not come Good.
Happy Listening!
A "Compactron" is not very compact. It takes up much more real estate than a 12AX7.
And it likely has more sections in it that take up much more filament power than a 12AX7.
Just my opinion.
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Pete Millett has done a lot of work with Compactron tubes...
Pete Millett's DIY Audio pages
RE: 12AX7, why use that instead of 6N2P?!
It's "compact" because you get more elements in the same tube. 12 pins allowed for double triode with pentode etc. Separately, these would take more space. Then there was the European socket tax or whatever. Incentive to reduce bottle count, no? 😀
Pete Millett's DIY Audio pages
RE: 12AX7, why use that instead of 6N2P?!
It's "compact" because you get more elements in the same tube. 12 pins allowed for double triode with pentode etc. Separately, these would take more space. Then there was the European socket tax or whatever. Incentive to reduce bottle count, no? 😀
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Look at the Bottlehead S.E.X. kit amp, for years it used the 6DN7 octal base tubes until the supply started to dry up, recently they switched to the 6FJ7 which is the compaction equivalent. Suddenly the tubes are really cheap as they are just an obscure tube used as vertical deflection oscillators in TV sets. Supply and demand....
i purchased lots of 6BH11 when they were U$1 each at Rogalskies....
one compactron tube to implement a Mullard 5-20 or even a Radford 120...
Attachments
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Compactrons are wonderful!
But . . .
If you are building a stand alone stereo phono preamp with a pair of 12AX7 tubes,
You may not want to use 2 compactions that each have an extra pentode along with the 2 triodes.
That is 2 unused pentodes, and the extra filament current to heat the cathodes.
And if you are using DC on the filaments, the current required goes up too.
If you decide to use AC on the filaments, I bet they are not spiral wound filaments.
Ask yourself, how low are the microphonics of a compaction that is used in a phono preamp?
Just something to think about.
But . . .
If you are building a stand alone stereo phono preamp with a pair of 12AX7 tubes,
You may not want to use 2 compactions that each have an extra pentode along with the 2 triodes.
That is 2 unused pentodes, and the extra filament current to heat the cathodes.
And if you are using DC on the filaments, the current required goes up too.
If you decide to use AC on the filaments, I bet they are not spiral wound filaments.
Ask yourself, how low are the microphonics of a compaction that is used in a phono preamp?
Just something to think about.
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for phono preamps, the 6C10, 6AC10, 6D10 are triple high mu triodes that can be used, the third triode can be used as cathode followers...
the 6BN11, a dual pentode can be configured a triode, imagination is key..
the 6BN11, a dual pentode can be configured a triode, imagination is key..
I remember when an article in Glass Audio gave quite a detailed story about a DIY portable stereo 45 amplifier.
Shortly after that, the price of 45 tubes went up drastically.
Then, a very few companies started making new production "45" tubes.
No, not original design, but the new production was living off the reputation of the original legendary 45.
I have not seen the same thing happen to Compactrons.
Are there any replacements currently produced anywhere in this world?
If you want to tube roll, there are probably more 12AX7 current production models from several manufacturers and countries, than just about anything else.
Shortly after that, the price of 45 tubes went up drastically.
Then, a very few companies started making new production "45" tubes.
No, not original design, but the new production was living off the reputation of the original legendary 45.
I have not seen the same thing happen to Compactrons.
Are there any replacements currently produced anywhere in this world?
If you want to tube roll, there are probably more 12AX7 current production models from several manufacturers and countries, than just about anything else.
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like all low power tubes like the 12ax7's, compactrons used that way can live forever, well almost...
btw, the 45's i see today, i can not differentiate between 2a3 nor 300b, they all look the same, same heights.... 😀
btw, the 45's i see today, i can not differentiate between 2a3 nor 300b, they all look the same, same heights.... 😀
I remember when I first saw the 2.5V filament "300B" tubes.
They were at the first VSAC (1997?), in Silverdale Washington
(Vacuum State of the Art Conference).
I would have bought a pair if I thought I could afford/justify it.
They were at the first VSAC (1997?), in Silverdale Washington
(Vacuum State of the Art Conference).
I would have bought a pair if I thought I could afford/justify it.
2a3 is 2.5vac and 300B is 5vac, i have them both with me, but i do not own them...
someone asks me to make an amp out of them...
someone asks me to make an amp out of them...
When I said a 2.5V filament "300B", I meant a Pseudo 300B, not a real 300B.
Yes, the filaments of the real 2A3 that I have is 2.5V; and the filaments of the real 300B I have is 5V.
Boutique tubes generally are not really the original tubes that they pretend to be.
Yes, the filaments of the real 2A3 that I have is 2.5V; and the filaments of the real 300B I have is 5V.
Boutique tubes generally are not really the original tubes that they pretend to be.
or a 2a3 plugged into a 300b amp and survived.......there was a thread about that here..What if 2A3 is inserted in 300b amp for a long time?
TonyTecson,
Is your picture of a tube a 4-65 Tetrode?
I once built a somewhat unusual single ended stereo amp using a pair of 4-65 outputs.
It was shown at one of the VSAC conferences at Silverdale, Washington.
There is quite a story behind why I even used 4-65 tubes there.
Is your picture of a tube a 4-65 Tetrode?
I once built a somewhat unusual single ended stereo amp using a pair of 4-65 outputs.
It was shown at one of the VSAC conferences at Silverdale, Washington.
There is quite a story behind why I even used 4-65 tubes there.