Replacing The Stock EH 6SN7 Tubes For Cary SLP 05


I run a Cary SLP 05 in the following setup

Cary Audio SLP-05 Preamp > Krell FPB 200 c Power Amp > Dynaudio Contour S3.4 Speakers

The Cary SLP 05 gives me that "live" atmosphere and soundstaging but I find that brass and horn instruments are still on the bright and harsh side with the stock tubes. It could be the Krell power amp. As such I thought of tube rolling and trying out some 6SN7's to hopefully give me more warmth and I guess a more euphonic and traditional tube sound. I will look towards replacing Tube Nos. 3 and 6 or the balanced buffer tubes first, retaining the stock EH 6SN7's elsewhere.

My shortlist follows below. Your opinions on how these tubes may sound in the Cary SLP 05 vis-a-vis each other is much appreciated.
Depending on how much you want to spend?

1. Shuguang "Black Treasure"
2. Sophia Electric
3. New production Tungsol
I don't have a Cary SLP 05 but have found RCA GT Gray glass from the 40's have a very rich midrange and well balanced from top to bottom. So far they are my favorite 6SN7.
The notes an info on this page, have proven very accurate, in my experience: ( I've tried every tube in the top 10, on this listing, in the last few years. The National Union(VT-231), RCA(VY-231) and CBS/Hytron(6SN7GT) were the warmest(in that order). The bottom gettered tubes, from the 40's and 50's, are the best sounding of the NOS 6SN7 family. The exception to that is the Sylvania, tall bottle 6SN7W, but- That one definitely does NOT fit your desire for a warmer sound. BTW: Nothing currently produced will match the presentation of NOS tubes.
I have tried a lot of 6SN7 tubes except Tungsol round plates.
Can't afford them. The best by far I have found is the 1962 nos russian 6HC8 tube from Upscale Audio. Tube is identical to 6SN7's and at $25 per tube must be tried. I have stopped tube rolling my 6SN7's because of this tube
Thanks for the replies. The post truncated before I cpould write my shortlist which is as follows.

After reading numerous online guides (including the reference one on Head Fi) I have a shortlist as follows (with my read impressions in brackets):

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)

Your opinions on how these tubes may sound in the Cary SLP 05 vis-a-vis each other is much appreciated especially from those with prior experience with the same equipment.

You should try the Pavane 6sn7 in the tube #1 and 3.They made a big different in my Cary SLP 05.
Hi .I made a mistake, it should be tube #1 and 4 .
Based on my experience with 6SN7s in AtmaSphere amps, I would recommend RCA for NOS and Ming Da for new. The Ming Das don't get much press, but they sound quite nice, and look really cool, too.
Does Pavane really make a 6SN7? I thought they were made by Shuguang, and as such, already have a 6SN7 in their Treasure line? Not sure though.
If you want a warm sound; the Tung-Sol round plate is not your cup-o-tea anyway. It's my fav, because of it's very clean, non-euphonic(my taste) presentation. I'm using them as drivers, with Sylvania 6SN7W's, as phase splitters(another very uncolored tube), in my mains monoblocks. The Brimars would represent the other end of the temp spectrum. Brit valves, like Mullard(ECC33) and Brimar(CV1988/6SN7GT), tend to be much warmer than those European or American manufactured, and well worth seeking out. BTW: don't skip finding a Mullard(Blackburn plant)GZ34 rectifier, as that will also transform your unit, in a very pleasant way. Matter of fact; I'd probably start with that position and tube.
Thanks for all the feedback so far.

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.
A circuit using a pair of tubes(one per channel), in any stage(gain/splitter/buffer), will have better balance if the tubes are matched. Whether you can discern the difference or not(numerous variables), is another matter. Of course if you have a number of stages, and each has mismatched tubes; the effect would be cumulative.
Thanks Rodman,

Do I stick to the +/- 5% tolerance level in tube strength test levels for tubes that are manufactured around the same period? In other words, if I follow this, can I purchase loose tubes and then match them and adjust for imbalances using the balance controls on the pre?

The reason I'm asking is because many of the listings on eBay are for single tubes or multiple tubes that seem to be "loose". Even a lot of them that are said to be matched pairs have different appearances, date codes, labels, etc. but are said to be electrically matched.

I guess it's unfortunate that tube buying at reasonable prices seem to be a crapshoot.
Most of the 6SN7 family tubes that I've purchased, have been in matched pairs. They are worth the wait and cost. Avoid any, that claim to be matched, but are not the exact same tube(internal appearance). A difference in presentation, between your channels, is almost certain to result. I've bought pairs that were identical in appearance/internal structure, but labeled differently(ie: Sylvania 6SN7W/6SN7A), and had differing date codes, but were perfectly matched in sound and electrical measurement. The 5% figure is a good one. Also, the triode to triode balance should be close, for each tube. Buying loose tubes, from different people would be a crapshoot, given that few tube sellers will have the same tube tester, and if they did; how close would the calibration be between them?
I have no affiliation to Brent Jesse other than as a customer, thought this link to his 6sn7 webpage might give you so insights on various tubes
I use several 6SN7's in my Atma-Sphere MP-1 and MA-1s(20 total) plus two in my Modwright/Sony 5400 and two more in my Cary SLI-80 all-triode F1. I've accumulated at least 70 or 80(lost count) NOS 6SN7's over the past few years including all the ones mentioned above; several Tungsol black glass, red base RCA 5692's, gray glass RCA VT231's, nickel base Sylvania's, you name it, I've got it.

Rodman99999 gave you lots of good advice. I too love the old Tungsols and while I wouldn't describe them as lean like many of the Sylvania's, they are pretty neutral and won't add much warmth. If your Cary can handle the red base RCA 5692's, that's where I'd be looking; a very sweet tube, big spacious airy soundstage and images with plenty of flesh on the bones. If you're nervous about getting non-microphonic matched pairs(I would be) at the prices they're going for, you may want to just look into some later RCA GTA's or GTB's. They're still plentiful and cheap and they'll definitely give you what you're looking for.

Be careful if you're looking at TungSol black glass, RCA 5692's, RCA gray glass(GT or VT231) and the KenRads. Many of them have been recycled on Ebay and can be VERY microphonic. Id get some kind of guarantee if you spring for any of them OR, buy from a reputable dealer who'll give you a guarantee; Andy at Vintage Tube Services comes to mind.

Also, for the money, while the Black Treasure and Psvane's are supposed to be very good, you can probably pick up NOS RCA's for less and they'll most likely sound at least as good, if not better, AND I'll wager they'll last a lot longer than the Chinese tubes.

Finally, Rodman is exactly right about those Mullard/Blackburn GZ34 rectifiers. They sound great, last forever and it's fairly easy to find good reliable ones on Ebay or the 'Gon.
Ken Rad Black coated glass VT231 = 6SN7

Brimar CV1988 = 6SN7 with print on glass, not base, with O getter on bottom - My favorite

GE/CBS Hytron 5692 - another great choice. I have GE branded.
So which tubes does the SLP-05 not use in single-ended mode? The review in Stereophile stated that it does not use tubes 5&6, which is obviously an error. Mikey and/or Jtran plese help.
I have a Cary SLP 98P and I've never tried NOS tubes before. I just ordered NOS RCA tubes, replacing all of the chinese stock tubes that came with the 98P. I also ordered NOS tubes for my 300B tube amp. I'm looking forward to my first experience with NOS tubes. My system sounds a tad harsh now. Dealt with Andy at Vintage Tube.
I also own the SLP05 preamp and have nos tube rolled extensively through the years I have owned it. The best, by a good margin, are the Pope Holland 6SN7GT tubes from the 50's. I happened on 6 of these and in my system, the difference is incredable
I would highly recommend the Sophia Electric if you DON'T want euphonic, warm but DO want balanced, accurate top to bottom sound with superb placement, staging and dynamic capabilities, I suspect due to the careful matching that you are paying for. The dynamics with this tube was quite a revelation to me in my Supratek Syrah pre-amp. These are the best I have heard and while not cheap at 200.00 a pair they are better than any of the NOS I have heard and own. I would also consider Ahendler's and the RCA GTA, GTB's at less cost. I haven't heard the Tung Sol round plates but am familiar with most of the above recommendations, my very favorite being the Sylvania brown base but these are certainly not equal to the Sophias IMHO. I have been touting these tubes since I purchased them a few months back and while there was initially a bit of harshness the stunning balance was evident right from the get go. They have now smoothed out and the highs are absolutely exquisite, no harshness but extended and airy.

Of ALL the tubes mentioned above, I would stay clear of the Ken-Rad black glass VT-231 unless you are looking for euphonic, inaccurate and for a lack of better description, phasey sound that seemingly expands the soundstage but to my ears is the worst 6sn7 I have personally heard. For the life of me I don't understand why this tube is ever in the conversation. I have a pair that test almost new, no gas emissions, shorts or any other issues that would explain to me why they might sound as they do, oh well, different strokes I suppose.

Just an update.

I have tried using the RCA 6SN7 GT Grey Glass in the balanced input buffer positions with a quad of the stock EH in the positive and negative, left and right gain positions. This made the treble warmer and filled out the midrange - but probably a wee bit too much as some vocals got a bit chesty. I am guessing if I used RCA's all throughout it may be too much of a good thing. Using the stock EH in the balanced input buffer postions and a quad of RCA 6SN7 GT Grey Glass in the positive and negative, left and right gain positions did not do much to tame the bright treble - I am guessing the phase gain positions do not have as much of an impact as the balanced input positions(?).

I am trying to get a quad of early Sylvania 6SN7 GT's which are Chrome Domes but of the same construction as the 6SN7W's with black plates - has anyone heard these and how do you think they will sound with the RCA's in the balanced input buffer?
I think the Sylvania will provide a ton of clarity which might not be what you need. I had them in my Rogue and took them out fairly quickly as they had too much energy. Your mileage may vary. The Sylvania GTB of mid 50's vintage may work better.
I have read elsewhere that the Suguang Treasure CV181 tubes don't physically fit into the Cary SLP-05. Can someone (Jtran?) confirm if these tubes actually fit through the chassis?
The new Pavane CV181 (6SN7) would fit.
Jtran - there is no Psvane CV181 (6SN7). Do you mean the Shuguang Treasure 6SN7?
Go to ,you will see it.The psvane 6sn7 tube base is smaller than the treasure 6sn7 .So they fit in the Cary slp 05 perfectly.I'm using them in my Cary slp 05.
Hi Jtran. How does the sound with Psvane 6SN7 compare to the stock EH tubes?

I have tried a couple of different tube sets including RCA NOS GTB's but I keep coming back to the stock tubes which seem to provide more air and dynamics.
Thanks Jtran. Wow, those are expensive tubes.
Krisjan. You should consider Sophia 6sn7 .I prefer the Sophia over the Psvane 6sn7 in the Cary slp 05.
Kiwi .The Psvane 6sn7 will give you a very details and lust sounding.But I'm now using Sophia 6sn7 tubes in my Cary 05 ,the sophia tubes are more brigther and faster and seem beter match in the Cary 05 than the Psvane tube .They are both much nore detail and finest sounding tubes compared to the EH 6ns7.
There doesn't seem to be a consensus on which locations on the SLP-05 to replace tubes first. I've read 3 and 6, as the original poster plans, and I've read 1 and 4.

Which is it?

EDIT: Called Cary. They said to get full effect (if you are not going to replace all six at once), positions 1,2,4, and 5 should be replaced, as these are the gain stages.