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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 269

post #4021 of 7566
Guys is this a good version of 6n6p ?
http://m.ebay.com/itm/261261824230?nav=SEARCH&sbk=1
Can't afford 6n6p-ir right now.getting 6n6p.
Let me if you guys get a better deal.
Ordering tonight so reply soon !
post #4022 of 7566
Quote:
Originally Posted by gunnerwholelife View Post

Guys is this a good version of 6n6p ?
http://m.ebay.com/itm/261261824230?nav=SEARCH&sbk=1
Can't afford 6n6p-ir right now.getting 6n6p.
Let me if you guys get a better deal.
Ordering tonight so reply soon !
Why are you switching out the power tubes? Are not those ones you linked similar quality or less to the stock tubes that come with the MK III, or do you just want them as spares?
post #4023 of 7566
Quote:
Originally Posted by mordy View Post

 

Getting nervous, all the octal tubes that are recommended are really expensive! Are there any good alternatives that are less expensive?

 

It seems to me that there is considerable consensus the Tung-Sol JAN CTL 6SU7GTY is the best of the best in this tube family. And yes, these are expensive, but no where near as expensive as some of the 6DJ8s. To my way of thinking, rather than spend $50 on a bunch of octals of questionable quality, I would rather spend $50 to get the best of the best and be done. So I purchased the Tung-Sol and I have absolutely no plans to purchase another 6SL7 or 6SU7.

 

I wish I could say the same about the 6DJ8 family....lol  :)

post #4024 of 7566

Got today 3 Ken-Rad 6SL7GT's. They all have different plates. Silver, matt silver and charcoal.

1000

According to this post these should be second best sounding octal drivers. http://www.head-fi.org/t/100774/top-5-6sn7-s#post_1176885 Could one of these say something to mighty 6SU7GTY...

post #4025 of 7566

Hi Artsi,

 

Found this post below, which represents somebody's thoughts on the best TS 6SL7GTY. BTW, do you have one from 1951?

 

 

"I have given this type some notice in other threads from time to time, but I think it deserves more attention, since it isn't nearly so well known as its most common electrical near-equivalent, the 6SL7GT.

I've been using it in projects since 1967, and it was always Big B's front end tube (five of them in the current version). These are the three in the power amp chassis front end. Two of them ordinarily wear homebrew copper tube shields.

Image

The 6SU7GTY is one of several Tung-Sol proprietary winners. The familiar 5881 and 6550 are two other Tung-Sol winners, and two that made it into manufacture by other companies. Tung-Sol took the 6SU7GTY through several marks and construction styles, but apparently no other company picked it up. The closest thing to it, so far as I can see, is the 5691.

In fact, the Hytron 5691 shown in this view appears to be a duplicate, and I think it's a rebranded/relabeled 6SU7GTY (1951 mark).

Image

The 6SL7WGT (Sylvania) is probably the next closest equivalent, and two of those, with their brown bases, can be seen in the view above, in the rear row of tubes behind the 6SU7 trio.

Over the years, I've come to believe that the 6SU7GTY is to the 6SL7GT what the 7025 is to the 12AX7. In fact, I think it's not an exaggeration to call it "the octal 7025."

It features a low-loss micanol base (this helps improve the noise and signal loss factor). It carries Aquadag electrostatic shielding on the inside of the bulb. It is also tested with AC on the heaters for a low hum-and-noise characteristic, and it is tested for balance between its two triodes.

I first got acquainted with this tube during high-school years, via my former boss, on whose bench I had apprenticed for two junior-high summer seasons. He was an old Signal Corps vet, and he had many boxes full of WWII surplus tubes (wish I had them now! :wink:). A number of these 6SU7's were among them. I was able to get half a dozen to start with, and I built my first project with these tubes in 1967.

Since then, I have experimented with several marks of this tube (from World War II vintage through the late 1950's) over the years, but the mark you see here (1951 vintage) is far and away the best-performing version I have encountered.

It is somewhat microphonic if the micas are not snug against the glass, but earlier and later marks can be far worse.

They also tend to show up much worse for hum and noise. The 1951 mark seems much slower on average to develop heater-cathode leakage than other production runs (some later 1950's editions developed it fairly quickly!).

In this 1951 mark, it seems, they got everything as good as it gets with this type:

Image

For some years, these weren't hard to find, and they weren't pricier than ordinary 6SL7's. I found a number of them at RARSfest in the late 1970's, and got several more from Fair Radio at about the same time. Since then, I've been lucky enough to find a few, here and there, in mil-surplus lots that turned up at RARSfest and elsewhere. About 15 years ago, I found and snapped up a huge batch of those Hytron 5691 tubes that appear to be (and act like) rebranded 1951-mark 6SU7 tubes, going for next to nothing at Durhamfest.

These days, of course, things have changed. These tubes have been "discovered," as one look at any mark-1951 6SU7GTY's on "that auction site" will show you (the asking prices are egregious these days!) :( . I'm just glad I discovered this tube when I did, and stocked up on it long ago.

Guys with large lots of mil-surplus tubes should search them for this type, especially the 1951 mark. If you find any, treasure them and put them to work if you can, for you have some cherries that are definitely worth attention."
post #4026 of 7566

Hi Ctritical Bill,

 

Thanks for your detailed post.

 

The Q version comes from China. Based on previous experience, the VR tube should be the highest quality.

 

If I understand correctly, only one tube on the list is directly compatible with LDIII.

post #4027 of 7566
Quote:
Originally Posted by mordy View Post
 

Hi Artsi,

 

Found this post below, which represents somebody's thoughts on the best TS 6SL7GTY. BTW, do you have one from 1951?

 

I can't see any date codes etc on tubes or boxes. Otherwise top mica and all i can see looks to be like same like 1951 model.

post #4028 of 7566
Quote:
Originally Posted by mordy View Post
 

Found this post below, which represents somebody's thoughts on the best TS 6SL7GTY. BTW, do you have one from 1951?

 

Mine was manufactured in 1950, week 47, which is the week of November 19 - 25. Perhaps close enough. :)

 

post #4029 of 7566
Quote:
Originally Posted by gibosi View Post
 

Since the Amperex OG with halo getters could be considered a "reference" tube, I decided to pick one up and found one for $13, manufactured in 1967. With that, configured the amp to play 6DJ8 and began listening. I now understand AFB's observations regarding the US-Amperex 6922 (1964) and the OG. While lacking the ultra detail of the 6922, I feel that the OG is more enjoyable. Moreover, I prefer it over both the Tesla and Valvo (Hamburg) E88CC.

 

Next, I decided to roll in the Voskhod (1978) 6N23P, as I hadn't heard it recently. The Voskhod has a sonic signature quite similar to the OG, with a lush, almost warm mid range, but a bit more bass presence and punch, and excellent flow and liquidity. Moreover, the Voskhod's ability to resolve ultra detail is second to none. Gong through my playlist of favorite songs, I heard details that I have never heard before. This is a seriously good tube.

 

Hi G.

 

Interesting to note your preferences over the Tesla E88CC (gold pins & gold grids, I believe), especially as they are reputedly equal to the almighty Telefunken variant - in what are they lacking? Did you give them a good burn-in?

Am especially interested as 1: The Tesla PCC88s hammering my ears at the moment are really quite something. And 2: Am awaiting my own E88CCs, complete with gold pins and grids...hope I haven't wasted my money lol!!

 

I recognise what you say about the Voskhods, although mine are the 6N2P-ERs - the clear detail is astounding, and the delicate finesse in the treble is especially "sweet". Methinks there is a definite 'synergy' going on with the 6H30P-DRs...

 

But these Teslas seem to be giving MORE in general...especially with about 30+ hours on them.

 

Cheers

post #4030 of 7566
Quote:
Originally Posted by hypnos1 View Post

 

Interesting to note your preferences over the Tesla E88CC (gold pins & gold grids, I believe), especially as they are reputedly equal to the almighty Telefunken variant - in what are they lacking? Did you give them a good burn-in?

Am especially interested as 1: The Tesla PCC88s hammering my ears at the moment are really quite something. And 2: Am awaiting my own E88CCs, complete with gold pins and grids...hope I haven't wasted my money lol!!

 

I recognise what you say about the Voskhods, although mine are the 6N2P-ERs - the clear detail is astounding, and the delicate finesse in the treble is especially "sweet". Methinks there is a definite 'synergy' going on with the 6H30P-DRs...

 

But these Teslas seem to be giving MORE in general...especially with about 30+ hours on them.

 

Well, of course, I think this really comes down to personal preferences... While I do not have a Telefunken from the 6DJ8 family, I do have a Siemens PCC88, a Valvo (Hamburg) E88CC and the Tesla E88CC with gold pins and gold grids, and they all have a mid range characteristic of German production, which is less warm and lush than is typical of Dutch and British production. Given my ears and gear, I find that I much prefer the Amperex tonality, which is not as warm as the Mullard, but more forward and lush than my Siemens, Valvo and Tesla.

 

As the Tesla was NOS, I burned it in for 20 hours and then compared it directly to the Valvo. Mid range and treble for these two tubes is very similar, again typical of German production, but the Valvo had more bass presence, while the Tesla sounded "thinner".  As I liked the Valvo better, I then rolled in the OG. And again, personal preference, but vocals came alive. The OG has a lushness and richness, coupled with great flow and liquidity, that I find very seductive.

 

But as much as like the OG, I think my 1978 Voskhod 6N23P is just a bit better. And given that you can get these Voskhods for $3 to $5 each, they are a steal. You want to look for production years 1974 through 1979. :)

 

 http://www.head-fi.org/t/549508/schiit-lyr-the-tube-rolling-thread/8595#post_9625620

post #4031 of 7566
Quote:
Originally Posted by mordy View Post
 

Hi Ctritical Bill,

 

Thanks for your detailed post.

 

The Q version comes from China. Based on previous experience, the VR tube should be the highest quality.

 

If I understand correctly, only one tube on the list is directly compatible with LDIII.


Yes, I found the Q version a little later, supposed to be 'space grade' but still Chinese...

The others on my list may work but for my first try I selected the most suitable. There seem to be lots of american ones to choose from, all appear to be high quality. I would try some of those but shipping from America to this corner of the world has become too expensive.

On further listening to my 6N16B I am liking them more and more.

Next I would like to try a pair of single triodes that I could mount directly in the sockets.

 

These look very suitable :

http://www.ebay.com.au/itm/271211549190?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

and the seller has lots of other sub-miniatures.


Edited by Ctritical Bill - 11/18/13 at 11:44am
post #4032 of 7566

A small package came today with a US-Amperex 6922, production date, February, 1961. Like my 1964 US-Amperex, this one is also labeled Beckman, and since it was not labeled Amperex, I got it for $35.00 with free shipping! Again, there are some very good deals to be had by going after relabeled tubes. :)

 

After reading AFB's observations regarding the sonic differences between his 1962 and 1964 production tubes, I am very curious to discover if my 1961 tube sounds any different....

 

post #4033 of 7566

The lifetime supply of sub miniatures... 

http://www.ebay.com/itm/Raytheon-JAN-5702-WB-Stock-box-200-each-tubes-Very-Rare-tubes-NOS-New-A-/271324699266

 

It's not the 20,000 qty sale one but what can you do... :D


Edited by TrollDragon - 11/18/13 at 12:11pm
post #4034 of 7566

The best 6SU7GT I tried was the Tung Sol 1945 era. I would be facinated to try the Hytrons however (5691). I picked up a big stash of the 5692 (1961) by Hytron some 15 - 20 years ago and I am a great fan of these, even over my reds. These are much underated.

 

on a different subject (and a 12v tube SO NOT A DIRECT SUBSTITUTE here), the 12SX7GT is another unsung hero. Only made by RCA I think.

 

Vacuum Tube Valley had some good articles on these some 20 years ago inc 6SU7GT I think.

post #4035 of 7566
Quote:
Originally Posted by gibosi View Post
 

A small package came today with a US-Amperex 6922, production date, February, 1961. Like my 1964 US-Amperex, this one is also labeled Beckman, and since it was not labeled Amperex, I got it for $35.00 with free shipping! Again, there are some very good deals to be had by going after relabeled tubes. :)

 

After reading AFB's observations regarding the sonic differences between his 1962 and 1964 production tubes, I am very curious to discover if my 1961 tube sounds any different....

 

Looking forward to your impressions, if only to know whether or not I'm just hearing things lol.

 

Regardless, even if they turned out to sound the same as the '64s, those are fabulous tubes, that definitely won't be losing any value any time soon, and it's never a bad idea to have spares - especially at this price!

 

Speaking of price, like gobosi's been saying, you can find those tubes fairly cheap fairly easily, even branded Amp'ex. You just won't get matched pairs or even matched date codes or production years is all. If I told you how much I paid for my two - unmatched & different years which is a good thing in my case as it allows testing different flavors - 6922, you'd find it hard to believe. Anyway, paying 3-digit figures for one of these is silly and easy to avoid, unless you have a Lyr or whatnot, and need matched pairs.

 

I have to  say that these tubes, especially the early 60's ones, are actually quite rare on ebay. I must have gotten lucky since I bumped in to two separate auctions - hence the decent prices - sold from EU countries over the span of a week without even looking that hard. I haven't really found anything else since then lol...

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