6SN7 Tube Addicts
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LoryWiv

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CV181s are all the same electrical specifications. Real CV181s are .96 heater current draw or they are either defective or not a CV181. Now where it gets confusing is with the folks at PSvane and Shu-guang -- they went and threw a monkey-wrench into the works by marketing a line of "CV181" tubes that are not CV181s . Their CV-181 series tubes are NOT CV-181s at all, but are actually 6SN7s with .6 heater current draw. Why their marketing department decided to do that is beyond me. Even Grant HiFi had to put out a disclaimer that the PSvane CV181s they sell are NOT CV181s but are actually 6SN7 tubes, due to concerns with heater current draw specs being different between the two.

Hope this helps.
It does, yes. Thanks @Ripper2860 for helping a relative "tubey - newbie" make sense of this complex but endlessly fascinating topic. :smile_phones:
 
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ken6217

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I have a Cayin 300B amp that takes two 6SN7 driver tubes. The manual says that it also takes ECC32 tubes. I tried a pair of unused NOS Mullard ECC32 tubes tonight, and the sound seems to have some distortion. I know the tubes need breaking in but I hadn't heard this type of sound on new tubes before. Seems more prevalent in the bass. Could it be bad tubes, or is it break in? I’ve certainly had new tubes in my amp before but didn’t have this type of experience. Any ideas? Thanks.
 
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m17xr2b

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Could be dirty pins, try to clean them with some sandpaper or deoxit.

Never had distortion with ECC32 and 300B on the WA5 or any other tube amp. Could be your source is too hot as these have higher amplification. Try with something else like a phone see if it distorts.
 
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ken6217

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Thanks for the reply. I have Deoxit. I’ll give it a try.

When you say the source could be hot, what exactly did you mean? I’m using the amp as a headphone amplifier.
 
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ken6217

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By the way, will I damage the amp by using this while I’m testing to see if I can turn it around?
 
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m17xr2b

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Standard DACs should have 2V output from single ended and I think 4V for balanced. Some have 3V or even 4V output out of single ended and 6V for balanced, couple that with a higher gain input tube biased at the edge and it can distort depending on the operating point of the amplifier

Quick and not entirely accurate info:

Tubes are negativity biased on input. For example you can have -3V grid and couple that with a +2V input the tube never sees positive voltage on the grid(which would be bad).
I think gain also has an impact, ECC32 has 32 gain where 6SN7 has 20ish.

Say you have -3V grid with +4V input from a hot dac(hot meaning it has higher voltage that it should be), now you are overdriving the tube and can cause distortion.

What's your dac?

Shouldn't cause any harm, unless the tubes are bad are are near failure.
 
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ken6217

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Standard DACs should have 2V output from single ended and I think 4V for balanced. Some have 3V or even 4V output out of single ended and 6V for balanced, couple that with a higher gain input tube biased at the edge and it can distort depending on the operating point of the amplifier

Quick and not entirely accurate info:

Tubes are negativity biased on input. For example you can have -3V grid and couple that with a +2V input the tube never sees positive voltage on the grid(which would be bad).
I think gain also has an impact, ECC32 has 32 gain where 6SN7 has 20ish.

Say you have -3V grid with +4V input from a hot dac(hot meaning it has higher voltage that it should be), now you are overdriving the tube and can cause distortion.

What's your dac?

Shouldn't cause any harm, unless the tubes are bad are are near failure.
The DAC is a Metrum Pavane. 4V output.
 
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m17xr2b

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I've got the Pavane as well, it's not the cause unless there's some weird incompatibility between it and you amp which I doubt. Still, try another source to be sure.
 
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LoryWiv

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In addition to looking into NOS tubes, was considering the new production Psvane CV-181TII as drivers for my Feliks-Audio Elise and noted another new production option at about same cost: Northern Electric 6SN7. Does anyone have experience with one or both of these? Comparisons would be especially helpful. Thanks!
 
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TheSnafu

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LoryWiv

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LoryWiv

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Wondering if anyone has tried the Sylvania made Baldwin organ 6SN7 vintage tubes. They are not hard to source and fairly inexpensive. The concept that they were purpose-made for a musical instrument raises my hopes that they will perform well in my Felik Audio Elise as drivers. I realize, however, that may not necessarily be true so if anyone's used them as a driver tube, I'd really appreciate your impressions.
 
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attmci

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Wondering if anyone has tried the Sylvania made Baldwin organ 6SN7 vintage tubes. They are not hard to source and fairly inexpensive. The concept that they were purpose-made for a musical instrument raises my hopes that they will perform well in my Felik Audio Elise as drivers. I realize, however, that may not necessarily be true so if anyone's used them as a driver tube, I'd really appreciate your impressions.
https://www.head-fi.org/threads/the-6sn7-identification-guide.209782/page-13
 
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LoryWiv

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MasonStorm

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When using any of those two-other-tubes-in-a-converter-to-a-single-6SN7 contraptions (I have 6J5G's, 7193's and 76's with the appropriate two-to-one adapters from eBay merchants), is it more important to insert two tubes that are closely matched for plate current, or for transconductance? Which measurement takes precedence?
 
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