Sustitute 5842 for EC86

Hans Olofsson · 8th April 2010, 08:35 AM

I am planning a Phono Preamp using the 5842 tube. However, these tubes seems quite costly and I am considering replacing them for EC86 that I have available and are less expensive. Is that a good idea, and would that require a major redesign of the schematics?

revintage · 8th April 2010, 09:06 AM

Hej Hans,
The EC86 is a very good tube in RIAAs if you don´t get problems with microphony. The tubes does not have very much in common.

An option could be to use the EC86 as input tube and parallell the the two halves of a E88CC( or 6N6P=lower gain/lower Zout) at the output. Personally I find the EQ a little nweird but it will anyway work. But almost all component-values has to be changed.

Hans Olofsson · 8th April 2010, 09:42 PM

Thanks, The obvious is the ampl factor (u=68 for ec86 and 43 for 5842) and that would have to be lowered in circuit (?) The EQ network would have to be altered as well?
Any other suitable replacement tube for 5842 (aside from the 417)?

revintage · 9th April 2010, 05:26 AM

Quote:

(u=68 for ec86 and 43 for 5842)

Gain difference is only just above 4dB so no big deal

. If you don´t want more total gain you can go for something like 6N6P in the second stage it´s got 6dB lower gain. With E88CC second, total gain will be almost on par.

But still, whatever tube you go for componentvalues have to be altered. Or let´s say the complete circuit should be redsigned.

There are no easy to find substitutes to find for 5842. 6c45 comes to mind but seems hard to get nowadays.

Hans Olofsson · 13th April 2010, 06:03 PM

Thanks for your input, I understand that the schematics needs reworking and right now I am not in the position to do that. However- someone who has experience ( and a schematics) for a RIAA phono amplifier that would fit the EC86 tube? As I understand it , the tube would qualify very well as a base for a highquality phonoamp.
Regards/ Hans

db! · 08:51 PM

I have used the 6S3P-EV and 6S3P-DR as a cheap substitute for the 5842. Keep in mind that the max anode voltage is slightly lower than the 5842 and/or the WE417. Also keep in mind that the pinouts are not the same...

Hans Olofsson · 14th April 2010, 09:56 PM

Some confusion here, The 6S3P-EV seems to be listed as 6S3P-EV/EC86/PC86 tube at Tubes-Store.com - Vacuum tubes, capacitors, nixie, sockets. Wholesale & retail trade. Worldwide shipping. The 6S3P-DR might be an option. I am aware of the pinout and will change them accordingly.
Thank you all for your valuable information. /Hans

Allen Wright · 14th April 2010, 11:08 PM

The WE417/5842 is MICROPHONIC to a degree that in a mic pre you don't need to bother with a microphone!

A far better tube for phono prte is the Russki 6C45, or 6P45 if you like. Even more gM that the 417, far more consistant and much less microphonoc. In current production, and costs less than most NOS tubes.

But I don't understand the reson for the half passive, half active RIAA eq. Doing the active that way is VERY noisy because of the very high impedances seen at the grid of the second tube.

Regards, Allen

Hans Olofsson · 21st April 2010, 07:48 PM

I won´t argue about that, the designer has identified himself, and the schematics is from AudioXpress Jan 2010.
Russki 6C45, or 6P45 if you like: Do you mean the
cyrillic C (S) or P (R)? In that case the tubes are not identical?

Allen Wright · 21st April 2010, 08:35 PM

Quote:

Originally Posted by Hans Olofsson

Russki 6C45, or 6P45 if you like: Do you mean the
cyrillic C (S) or P (R)? In that case the tubes are not identical?

No idea. Maybe 6S45. Made by Reflecta, sold by Electroharmonix. I mean the single 9 pin triode with a gM of circa 45mA/V.

Regards, Allen

8th April 2010, 09:06 AM	#2
revintage diyAudio Member Join Date: May 2007 Location: Eskilstuna, Sweden	Hej Hans, The EC86 is a very good tube in RIAAs if you don´t get problems with microphony. The tubes does not have very much in common. An option could be to use the EC86 as input tube and parallell the the two halves of a E88CC( or 6N6P=lower gain/lower Zout) at the output. Personally I find the EQ a little nweird but it will anyway work. But almost all component-values has to be changed. __________________ Brgds Lars

13th April 2010, 08:48 PM	#6
db! diyAudio Member Join Date: Nov 2009 Location: Ontario	I have used the 6S3P-EV and 6S3P-DR as a cheap substitute for the 5842. Keep in mind that the max anode voltage is slightly lower than the 5842 and/or the WE417. Also keep in mind that the pinouts are not the same... Last edited by db!; 13th April 2010 at 08:51 PM.

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8th April 2010, 09:42 PM	#3
Hans Olofsson diyAudio Member Join Date: Feb 2007 Location: Lapland, Sweden	Thanks, The obvious is the ampl factor (u=68 for ec86 and 43 for 5842) and that would have to be lowered in circuit (?) The EQ network would have to be altered as well? Any other suitable replacement tube for 5842 (aside from the 417)?

13th April 2010, 06:03 PM	#5
Hans Olofsson diyAudio Member Join Date: Feb 2007 Location: Lapland, Sweden	Thanks for your input, I understand that the schematics needs reworking and right now I am not in the position to do that. However- someone who has experience ( and a schematics) for a RIAA phono amplifier that would fit the EC86 tube? As I understand it , the tube would qualify very well as a base for a highquality phonoamp. Regards/ Hans

14th April 2010, 09:56 PM	#7
Hans Olofsson diyAudio Member Join Date: Feb 2007 Location: Lapland, Sweden	Some confusion here, The 6S3P-EV seems to be listed as 6S3P-EV/EC86/PC86 tube at Tubes-Store.com - Vacuum tubes, capacitors, nixie, sockets. Wholesale & retail trade. Worldwide shipping. The 6S3P-DR might be an option. I am aware of the pinout and will change them accordingly. Thank you all for your valuable information. /Hans

14th April 2010, 11:08 PM	#8
Allen Wright R.I.P. Join Date: Dec 2001 Location: Schaffhausen Switzerland	The WE417/5842 is MICROPHONIC to a degree that in a mic pre you don't need to bother with a microphone! A far better tube for phono prte is the Russki 6C45, or 6P45 if you like. Even more gM that the 417, far more consistant and much less microphonoc. In current production, and costs less than most NOS tubes. But I don't understand the reson for the half passive, half active RIAA eq. Doing the active that way is VERY noisy because of the very high impedances seen at the grid of the second tube. Regards, Allen

21st April 2010, 07:48 PM	#9
Hans Olofsson diyAudio Member Join Date: Feb 2007 Location: Lapland, Sweden	I won´t argue about that, the designer has identified himself, and the schematics is from AudioXpress Jan 2010. Russki 6C45, or 6P45 if you like: Do you mean the cyrillic C (S) or P (R)? In that case the tubes are not identical?

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