Anybody ever tried EBC41 as 12AX7 substitute?

Kenneth Zhu · 9th May 2011, 05:41 AM

By coincidence, I got a quad of EBC41 manufactured by Mullard in the 50's, by judging their EVM code. What is surprising to me is that they have much similarity to Mullard's 12AX7 made in mid-50's, for example, D-getter and half-vaporized gas absorber. It is actually a single triode, and the triode is shielded by a metal mesh like that in an early Mullard's EF86. I examined its PDF mannual and found that it is originally designed for radio receiver application, but its linearity, as shown by the mannual, is equal to or even slightly better than that of a 12AX7, particularly at relatively low working point. I just wonder if there's any audiophile has ever tried it as a replacement (indirect, for its structure and pin layout) for 12AX7, and how's the outcome?

Kenneth Zhu · 10th May 2011, 09:58 AM

Gee... Anybody can give me a hint?

Shoog · 10th May 2011, 10:04 AM

Most things in life are a suck it and see situation. Its the brave soul who push out to new frontiers who everyone follows.
Since you have them - give it a try and see if you can generate a fanclub for the EBC41.

Shoog

revintage · 10th May 2011, 10:41 AM

It is not a 12AX7 substitute! But 5751 has exactly the same characteristics.

DF96 · 10th May 2011, 01:09 PM

This appears to be the same characteristics as EBC90/6AT6, so same valve on a different base. Designing a new valve was hard work in the days before computers, so a successful design was simply repackaged on different bases. Also made things easier for the circuit designer, who also did not have a computer.

It also looks remarkably similar to the octal 6Q7, so the same circuit can be used with three generations of valves. EBC81 too, and possibly EBC21.

the_manta · 10th May 2011, 01:14 PM

I once tried EBC91 which has ECC83 triode section. Worked well, but huge spread in dynamic (µ) and static (-Ug) parameters in my batch.
These tube were designed for consumer radio equipment and weren't selected or matched.
I have to nice old wooden tube radios using them and that's exactly where they belong. I can't stand words like "audiophile" or something for tubes like this.

davorin · 10th May 2011, 01:34 PM

Triode at EBC41 (EBC81, EBC90) is electric and mehanic copy 1/2 ECC81 tube, not ECC83!

DF96 · 10th May 2011, 01:53 PM

I don't think so. Check the datasheet. There is more to a triode than mu! EBC41/81/90 has a high impedance triode. ECC81 is a low impedance triode, similar mu but much higher gm and lower Ra. From memory, EC92 is half an ECC81.

barrymagrec · 10th May 2011, 07:21 PM

The Mullard maintenance manual (circa 1956) suggests that the EBC41 is very similar though not identical to the ECC83, no similarity at all to the ECC81. As has been pointed out it is also even more like the EBC90, or DH77 as I tend to think of them. I haven`t heard an amp using the EBC41 but the old EMI TR50 amp using a DH77 and N78 made a very nice sound with a reasonably efficient speaker.

Barry

Kenneth Zhu · 11th May 2011, 11:55 AM

I've gathered 4 Valvo metal-based, 4 Mullard glass-based and 2 Telefulken glass-based, and also 5 Telefulken glass-based EBC81 which is akin to EBC41. I plan to build a Jadis JP80 preamp by using these tubes in stead of 12AX7。Perhaps as the_manta pointed out, matching would be a challenge. Anyway I'd like to have a try, as it would be very costly to find 12AX7 made in this age by these shining brands.

9th May 2011, 05:41 AM	#1
Kenneth Zhu diyAudio Member Join Date: Sep 2003 Location: Deyang, Sichuan, P.R.China	Anybody ever tried EBC41 as 12AX7 substitute? By coincidence, I got a quad of EBC41 manufactured by Mullard in the 50's, by judging their EVM code. What is surprising to me is that they have much similarity to Mullard's 12AX7 made in mid-50's, for example, D-getter and half-vaporized gas absorber. It is actually a single triode, and the triode is shielded by a metal mesh like that in an early Mullard's EF86. I examined its PDF mannual and found that it is originally designed for radio receiver application, but its linearity, as shown by the mannual, is equal to or even slightly better than that of a 12AX7, particularly at relatively low working point. I just wonder if there's any audiophile has ever tried it as a replacement (indirect, for its structure and pin layout) for 12AX7, and how's the outcome?

10th May 2011, 10:41 AM	#4
revintage diyAudio Member Join Date: May 2007 Location: Eskilstuna, Sweden	It is not a 12AX7 substitute! But 5751 has exactly the same characteristics. __________________ Brgds Lars

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10th May 2011, 09:58 AM	#2
Kenneth Zhu diyAudio Member Join Date: Sep 2003 Location: Deyang, Sichuan, P.R.China	Gee... Anybody can give me a hint?

10th May 2011, 10:04 AM	#3
Shoog diyAudio Member Join Date: Aug 2002 Location: Eire	Most things in life are a suck it and see situation. Its the brave soul who push out to new frontiers who everyone follows. Since you have them - give it a try and see if you can generate a fanclub for the EBC41. Shoog

10th May 2011, 01:09 PM	#5
DF96 diyAudio Member Join Date: May 2007	This appears to be the same characteristics as EBC90/6AT6, so same valve on a different base. Designing a new valve was hard work in the days before computers, so a successful design was simply repackaged on different bases. Also made things easier for the circuit designer, who also did not have a computer. It also looks remarkably similar to the octal 6Q7, so the same circuit can be used with three generations of valves. EBC81 too, and possibly EBC21.

10th May 2011, 01:14 PM	#6
the_manta diyAudio Member Join Date: Nov 2006 Location: Munich, Bavaria	I once tried EBC91 which has ECC83 triode section. Worked well, but huge spread in dynamic (µ) and static (-Ug) parameters in my batch. These tube were designed for consumer radio equipment and weren't selected or matched. I have to nice old wooden tube radios using them and that's exactly where they belong. I can't stand words like "audiophile" or something for tubes like this.

10th May 2011, 01:34 PM	#7
davorin diyAudio Member Join Date: Aug 2005 Location: Zadar, Croatia	Triode at EBC41 (EBC81, EBC90) is electric and mehanic copy 1/2 ECC81 tube, not ECC83!

10th May 2011, 01:53 PM	#8
DF96 diyAudio Member Join Date: May 2007	I don't think so. Check the datasheet. There is more to a triode than mu! EBC41/81/90 has a high impedance triode. ECC81 is a low impedance triode, similar mu but much higher gm and lower Ra. From memory, EC92 is half an ECC81.

10th May 2011, 07:21 PM	#9
barrymagrec diyAudio Member Join Date: Apr 2010	The Mullard maintenance manual (circa 1956) suggests that the EBC41 is very similar though not identical to the ECC83, no similarity at all to the ECC81. As has been pointed out it is also even more like the EBC90, or DH77 as I tend to think of them. I haven`t heard an amp using the EBC41 but the old EMI TR50 amp using a DH77 and N78 made a very nice sound with a reasonably efficient speaker. Barry

11th May 2011, 11:55 AM	#10
Kenneth Zhu diyAudio Member Join Date: Sep 2003 Location: Deyang, Sichuan, P.R.China	I've gathered 4 Valvo metal-based, 4 Mullard glass-based and 2 Telefulken glass-based, and also 5 Telefulken glass-based EBC81 which is akin to EBC41. I plan to build a Jadis JP80 preamp by using these tubes in stead of 12AX7。Perhaps as the_manta pointed out, matching would be a challenge. Anyway I'd like to have a try, as it would be very costly to find 12AX7 made in this age by these shining brands.

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