Seduction And Reduction Tube Equivalents

[Grainger49]

This thread is getting started to explore tube types, different numbers, that can be used in the Seduction (and now Reduction) without any circuit modifications.  That is, drop in equivalents.

These are the ones I have found.  I will modify the OP with others as posters contribute other numbers.

If anyone finds that I have a tube with the wrong pin out, or higher heater current than the Seduction can supply please post and I will modify the OP accordingly.

Seduction Tube Equivalents (in numerical order):

6DJ8
6DJ8 (just the generic, many below are better spec tubes)
6N23P (P9 is shield) -EV are tighter specs
CV2492
CV2493
CV4108
CV4109
CV4110
CV5231
CV5354
CV5358
ECC88
E188C
E188CC
E288CC ?
E88CC
6922
7308

Edit: Three dropped.

 

[coca]

6H23 will work with no changes.

Bernie.

 

[JC]

Just to be clear, you are referring to the Russian tube, correct?

 

[Grainger49]

Jim,

Yes, the H is a Cyrillic N.  And the P at the end is actually Pi, which doesn't appear on my keyboard.

 

[JC]

Which explains why one may see them listed as 6N23, 6H23N, 6H23n, and sometimes with a "-EB" suffix.

As if the West didn't have enough numbering systems of its own for tubes!  Lord knows what the Chinese system looks like...

 

[Grainger49]

Yes, the Pi really looks like an N, the N is an H and they use B instead of V for volts.  I'm guessing that there is no V in the Cyrillic alphabet.  

The -EB suffix often denotes the higher tolerance tubes, a select tube.  I just ordered 4 from RU Tubes in Moscow.

 

[NotBen]

I read some posts on the old asylum board from a few years back regarding some of the tubes on this list, specifically the CV2493 and the CV5358: http://tinyurl.com/25g7ano
I just received my Seduction kit and want to know if there has there been a change to the PT-1 or if the old list I linked to is still in question. Or, if for those specific tubes it is a matter of type 1 versus type 2, etc.
Thanks.

 

[Grainger49]

Yes, all those are within the range of the PT-1.  The PT-1 can supply rectified and filtered 365 mA per tube.  The design is for 365mA per tube.  Everything on the list is 365mA or less. The two you mention are direct drop in replacements for the 6DJ8 (same heater current). The Seduction manual lists the supplied tubes as 6DJ8/6922.

If you want to use type 2, 3 or 4 tubes the series resistor in the heater supply could be adjusted to bring any of the other types back to exactly the design voltage.  I don't think that the 6DJ8 was run at a full 6.3V.  (5.7-6.3V according to PJ in Reply #12 below.)

 

[NotBen]

Very good. Thanks!

 

[jamestw]

Hi Grainger,
How's about this NOS VALVO AMPEREX PCC88 (7DJ8) tube selling at eBay now :
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250361475103#ht_8010wt_1135

In descriptions: ......Real PCC88 are drop in replacements for ECC88/6DJ8/E88CC with a slightly higher heater specification of 7 volts producing a much longer life and lower noise threshold when used in place of ECC88/6DJ8.

I'm still looking for a pair of spare tubes for my Secduction, Don't know if this kind PCC88 tubes can be directly replaced ?

Thanks,
james

 

[Grainger49]

Yes, they look similar.  But it is a 7.6V heater.  The 6DJ8 variants are 6.3V.  There will be a change in the tube's sound with more than a volt low on the heaters.

 

[jamestw]

Thanks, Grainger.

james

 

[Paul Joppa]

Seduction runs the heaters at 5.7 to 6.0 volts, which gives the "longer life and lower noise" effect. Running a 7DJ8 that low will give very long life and no noise at all - but no sound either of course; the heaters will be too cold to function!

 

[jamestw]

OK. now I understanded, Thank you, Paul.

james

 

[8452]

How about the 6ES8? I inherited 30 Bugle Boys so I hope its OK to use them. I visited several on-line tube substitution guides and this tube is listed as a 6DJ8 sub.

 

[Paul Joppa]

The 6ES8 is a "semi-remote cutoff" tube, meaning the gain is highly variable depending on the current. It is built that way so that the gain can be automatically adjusted for different radio stations. In audio, that means it is nonlinear as all get-out. It's not suitable for audio. In Seduction, it will also not have anywhere near enough gain.

This tube is often listed, and sometimes sold, as a 6DJ8 equivalent - this is either a product of ignorance or fraud. My opinion of course.

 

[Dobs]

Seduction runs the heaters at 5.7 to 6.0 volts, which gives the "longer life and lower noise" effect. Running a 7DJ8 that low will give very long life and no noise at all - but no sound either of course; the heaters will be too cold to function!

It's the problem i have with 6N1P tube in my Seduction, some work and some dont.

 

[Grainger49]

The 6N1P draws twice the heater current than Seduction was designed for.  The Seduction transformer will burn out after a while using them.  But they are good sounding tubes and were used in the design stage as reported by PJ.

If you want to run the 6N1P, then buy a transformer that will give you double the current for the heaters and put a 500k ohm resistor to ground where the 1M ohm resistor is after the interstage coupling cap and before the grid stopper 220 ohm resistor.  After getting a higher current transformer in there you might need to adjust the voltage on the heaters by changing the series resistor in the heater supply.  This is also according to PJ.

 

[Dobs]

The 6N1P draws twice the heater current than Seduction was designed for.  The Seduction transformer will burn out after a while using them.  But they are good sounding tubes and were used in the design stage as reported by PJ.

I hope i didnt damaged too much my transformer because im using 6N1P for about 2 years now with around 800h of play.

If you want to run the 6N1P, then buy a transformer that will give you double the current for the heaters and put a 500k ohm resistor to ground where the 1M ohm resistor is after the interstage coupling cap and before the grid stopper 220 ohm resistor.  After getting a higher current transformer in there you might need to adjust the voltage on the heaters by changing the series resistor in the heater supply.  This is also according to PJ.

Can you guide me to get a good transformer? And also give me more details on the parts to get and the way to locate them. I have build my Seduction 4 or 5 years ago and i dont have anymore documentation about it.

Thanks again,

 

[Paul Joppa]

I have not yet found a good alternative - in fact, we developed the PT-1 because there were no really suitable transformers even for the 6822 version.

The simplest approach would be to run the 6N1P on AC heater power, bypassing the rectifiers entirely and grounding one side of the winding. This will reduce the RMS current to within spec. There is risk of hum, but there are various inexpensive ways to improve that. I've posted this for years but I don't remember anyone having tried it.

The next simplest approach would be to replace the heater power supply with a 6vDC external supply, as many people did with the original Foreplay years ago. It should be rated for 1.2 amps or greater.  These are usually the kind that have a small box to plug into the power outlet, the so-called "wall wart". Caution - some of these are fine, some are junk, and it's hard to tell which is which!