6P3S-E direct replacement for el34?

[Mr Boochie]

The 6P3S-E is NOT equivalent to a 6L6GC. It won't manage 30W anode dissipation, nor have I ever seen reliable specifications for screen grid dissipation or voltage. Reputable sellers only rate it equivalent to the 5881, and it was relabeled and sold as this type for a number of years. The 6P3S-E is also not equivalent to the EL34. There are a number of significant differences, such as transconductance, voltage ratings and optimum load impedance. I know it's been subbed for the EL34 in certain amplifiers (including the Dynaco ST-70), but there are reports that this produces a different sonic signature and reduced performance.

Just to be clear, I'm a big fan of the 6P3S-E, and I bought a large lot directly from Russia quite a few years ago. It's a terrific tube that can sub for many 6L6 variants in many different amplifiers, but it's important to know its limitations. I use them in my Citation V, but the amplifier has been modified for reduced screen voltage. I'm also careful to bias the tubes below 25W dissipation.

Jack

Truth!

I run them like 5881/6L6WGC. A conservative 18-20 watts per tube, Class AB1, in a push-pull arrangement. Then, they last and have good headroom.

 

[MNmarantz]

Appears to be cathode biased, so there's a good chance the 6P3S-E's will be running way too hot in your amp.

I don't see anything on their website about running other output tubes.

jeff

I had messaged them about this and am waiting to hear back. Maybe they will work in my primaluna??? That amp is a true auto bias. Or I’ll have to flip them on Bartertown. For all the ease of cathode/autobias I can see why the real tube guys don’t like them.

 

[Mr Boochie]

I had messaged them about this and am waiting to hear back. Maybe they will work in my primaluna??? That amp is a true auto bias. Or I’ll have to flip them on Bartertown. For all the ease of cathode/autobias I can see why the real tube guys don’t like them.

Just an aside. Have you tried KT77 or 6CA7 tubes?

Thanks!

 

[TriodeLuvr]

Raven blackhawk

A quick search indicates this amp uses 6L6GC. Also, based on its output power of 20W/ch, I would assume voltages are not crazy high. It might be good to confirm this before plugging in the new tubes.

About bias, triode curves provide a quick comparison. According to charts, the 6L6GC with 400V on screen and anode draws 43mA with -40V grid bias. The 6P3S-E under those same conditions draws about 48-49mA. This difference in current draw will be moderated if cathode bias is used, and depending on other conditions, it's possible no changes will be needed to sub the 6P3S-E. I'll add that even with fixed bias, I haven't experienced the degree of difference shown when comparing the charts. I've subbed the 6P3S-E recently for NOS Sylvania 5881 and several used 6L6GC, and bias changed very little. The 6P3S-E also measures like any other 6L6 variant on my Hickok.

I won't bother uploading the 6L6GC triode graph, because it's readily available elsewhere online. Here's the 6P3S-E in triode, which might be more difficult to find:



Jack

 

[MNmarantz]

Just

Just an aside. Have you tried KT77 or 6CA7 tubes?

Thanks!

Sadly ive only used the stock el34 in the primaluna.

 

[TriodeLuvr]

Just an aside. Have you tried KT77 or 6CA7 tubes?

Thanks!

A quad of either of those will draw much more filament current than 6L6GC.

 

[MNmarantz]

A quick search indicates this amp uses 6L6GC. Also, based on its output power of 20W/ch, I would assume voltages are not crazy high. It might be good to confirm this before plugging in the new tubes.

About bias, triode curves provide a quick comparison. According to charts, the 6L6GC with 400V on screen and anode draws 43mA with -40V grid bias. The 6P3S-E under those same conditions draws about 48-49mA. This difference in current draw will be moderated if cathode bias is used, and depending on other conditions, it's possible no changes will be needed to sub the 6P3S-E. I'll add that even with fixed bias, I haven't experienced the degree of difference shown when comparing the charts. I've subbed the 6P3S-E recently for NOS Sylvania 5881 and several used 6L6GC, and bias changed very little. The 6P3S-E also measures like any other 6L6 variant on my Hickok.

I won't bother uploading the 6L6GC triode graph, because it's readily available elsewhere online. Here's the 6P3S-E in triode, which might be more difficult to find:

View attachment 3172298

Jack

So you’re saying there’s a chance! Thats some great info triodeLuvr. And you are quick on the draw! I’ll wait until I hear from the folks at Raven before trying them.

 

[Mr Boochie]

A quad of either of those will draw much more filament current than 6L6GC.

Yes, but aren't the amp's OEM tubes EL34?

 

[MNmarantz]

Yes, but aren't the amp's OEM tubes EL34?

Sorry I prob caused some confusion. The Ravens OEM are 6l6gc. I mentioned potentiallly using the 6P3S-e in my primaluna if the Raven is not compatible with the 6P3S-E

 

[Mr Boochie]

Sorry I prob caused some confusion. The Ravens OEM are 6l6gc. I mentioned potentiallly using the 6P3S-e in my primaluna if the Raven is not compatible with the 6P3S-E

Okay!

Thanks for the clarification.

 

[TriodeLuvr]

I’ll wait until I hear from the folks at Raven before trying them.

You can probably determine this for yourself if you have a schematic, especially if it lists a few power supply voltages. Good luck with everything!

Jack

 

[Blackdog61]

I ran them for a few months in my Dyna ST-70, keeping the bias under 45ma and they sounded good. After buying a nice quad of RFT I’m not going back. Fun to experiment but that‘s all it was for me.

 

[Mr Boochie]

I ran them for a few months in my Dyna ST-70, keeping the bias under 45ma and they sounded good. After buying a nice quad of RFT I’m not going back. Fun to experiment but that‘s all it was for me.

RFT EL34. Right?

Very good tubes.

 

[Blackdog61]

RFT EL34. Right?

Very good tubes.

Yes. Very happy with them.

 

[Mr Boochie]

Yes. Very happy with them.

I wish I had bought more when they were cheaper. The sound is very close to Blackburn xf1 and xf2.

 

[MNmarantz]

I wish I had bought more when they were cheaper. The sound is very close to Blackburn xf1 and xf2.

I feel the same about my matsushita’s