The Reference 6SN7 Thread

[Skylab]

ALL tubes are at least slightly microphonic.

 

[Wedge]

I guess I meant a little more than slightly microphonic.  

 

[jamato8]

Quote:

ALL tubes are at least slightly microphonic.

Well yes but I think you know what we are getting at. It is like adding reverb to a dry recording to give it life, which is done for many studio recordings or they fall flat. 
 
Quote:

I guess I meant a little more than slightly microphonic.  

The old pencil eraser test. Rap, rap, hey this tube is microphonic. Look, whack, whack, see I can hear that!! what a junk tube! :^) Playing with some of the old tubes that I like, late 1920's to the early 1930's, there are some real gems. Some would make excellent microphones. Others have just the right touch. It is all about balance. 
 
 

 

[Skylab]

Quote:

Well yes but I think you know what we are getting at. It is like adding reverb to a dry recording to give it life, which is done for many studio recordings or they fall flat. 
 

 
Indeed, I was just playing.  Yes, sometimes a slightly microphonic tube can sound better than one that isn't. Unless a tube is horribly microphonic, I really don;t worry about it.
 
 

 

[mikey8811]

Hi
 
After a long and fruitless attempt trying to hunt down some RCA Grey Glass 6SN7's , I came across these on eBay
 
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320713374641
 
They don't look like a matched pair as the colour of the lettering on each tube label is different.
 
The seller description says:
 
[size=x-small][size=large][size=medium]104 & 102 and 102 & 102, well above typical NOS tubes reading. The minimum good reading of the 6SN7 tube on this tester is 50 & 50. Short and Gas testings passed for both tubes.[/size][/size][/size]
 
Sound OK?
 
How do these military spec ones sound ? Anyone try them in the balanced output positions ie. tube nos. 3 & 6 in a Cary SLP 05 preamp? Or would I be better off with the black base silver label RCA 6SN7 GTB's?
 
Thanks

 

[jamato8]

Hard to say what you would be better off with as everyones ear is different. I have a number of the grey glass 6SN7's and I always found them to be too warm for my liking and lacking in clean detail. They have followers so for the right price they are worth a listen I guess. As far as internal construction on the two being exactly the same, I wouldn't know from the image. They appear to be made in 1945 and 1944. 

 

[dminches]

He is a good seller.  I have purchased stuff from him before and I have been pleased.  That's not to say that you will like the sound of the tubes...

 

[mikey8811]

Hi
 
Thanks for the feedback.
 
Not much luck winning these auctions.
 
Currently bidding on similar RCA VT-231 Grey Glass, Brimar 6SN7 GT, Tungsol BGRP (long shot - looks very expensive) and black base clear glass RCA 6SN7 GTB from 1950's.
 
Would someone with the experience characterise the sounds of these tubes relative to each other and the red base RCA 5692's?
 
Thanks

 

[mikey8811]

Hi
 
Up for some feedback please.
 
This is my impression based on research (mostly from this thread and other online sources) - your comments please on if they are appropriate.
 
[size=smaller][size=larger]1. RCA 5692 Red Base - a long shot as this seems expensive (the best of the RCA's with a warm midrange, wide soundstage, smooth highs which are still somewhat extended, laid back and maybe rolled off)

2. Brimar 6SN7 GT - most likely the black base clear glass as the brown base dark glass one is probably too expensive (warm with a wide soundstage and smooth extended highs but more dynamic than the RCA sound)

3. Tungsol Black Glass Round Plates - again a long shot as it is probably over my budget (the best all rounder with all the above attributes quite balanced out)

4. RCA VT-231 Grey Glass (a poorer cousin of the 5692 red base with similar attributes at a lower price)

5. RCA 6SN7 GTB - (one more notch down in the RCA sound with similar attributes at a lower price)[/size][/size]
 
Also, do preamp tubes need to be matched pairs? I keep getting conflicting opinions on this. Cary says yes but many others say only power tubes need matching.

 

[Anaxilus]

.

 

[williaty]

Is there any way to use a multimeter to verify that a 6SN7 is "safe" or not? Obviously, it can't tell you if there's still life in the tube, but can you at least test resistances between pins to verify that it isn't shorted and won't blow up your amp?

 

[Elysian]

This thread is a lifesaver!  Been hunting all over for 6SN7 (NOS and new production) reviews, and I think this thread has saved me a lot of wallet pain.
 
Does anyone have experience pairing the new production Electro Harmonix 6SN7 (gold pin) with either the Shuguang Gold Treasure 300B-Z or Psvane 300B-T tubes?  I realize the pairing will also depend on how I want to adjust the final SQ of the gear.
 
Seems like the majority of people feel the new production Electro Harmonix 6SN7 tubes have better bass and overall precision in the sound than the Shuguang Treasure 6SN7 at a fraction of the price.  The EHes also seem to compare well with the NOS Sylvania and Tung Sol 6SN7s.

 

[MacedonianHero]

Quote:

This thread is a lifesaver!  Been hunting all over for 6SN7 (NOS and new production) reviews, and I think this thread has saved me a lot of wallet pain.
 
Does anyone have experience pairing the new production Electro Harmonix 6SN7 (gold pin) with either the Shuguang Gold Treasure 300B-Z or Psvane 300B-T tubes?  I realize the pairing will also depend on how I want to adjust the final SQ of the gear.
 
Seems like the majority of people feel the new production Electro Harmonix 6SN7 tubes have better bass and overall precision in the sound than the Shuguang Treasure 6SN7 at a fraction of the price.  The EHes also seem to compare well with the NOS Sylvania and Tung Sol 6SN7s.

Not sure where you got this impression? I happen to have the  EH Golds and Treasures and the Treasures are much better tubes IMO. Cleaner, more balanced and extended.
 

 

[Elysian]

From some of the posts earlier in this thread, as well as various impressions on the Treasures on other forums.
 
Aside from the Grant Fidelity testimonials, yours is one of the few comments I've seen that say the Treasures are both cleaner and more extended.  One of the main complaints I've read about the Treasures is that they don't reproduce certain frequencies that well.  At least from what others have said the Treasures seem good if there are particular imbalances in the system.  The Tung Sols seem to be well-favored, but I'd prefer new production over NOS.
 
I'll probably need to pick up a quad of 6SN7s soon, so I'm looking for something with a good price-performance ratio (with good soundstaging, bass, and transparency), and is reliable.

 

[Anaxilus]

Agreed w/ MH.  I have not heard the EH gold pins but the standard EH's are crap and my bottom of the barrel tube.  I have not heard a worse tube.  I need to get rid of all of them.  Pretty much worthless IMO.  The current Tung Sol GTB's are better than the EH's generally IME.  They look identical in build to the EH's except brown base but the GTB's have a bit more chrome on top than the EH's.  I've been through about 8 GTB's and 6 EH's, pretty consistent difference IMO.  Not night and day but enough to matter.  Though I'm dealing w/ 6 output tubes so YMMV.  The Treasure I heard was bright, analytical, precise, weak on the low end if it had any.  The EH's were flabby, bloated, distorted crap.