Thread to share Isabella tube rolling experience

6rs · « **on:** 5 Sep 2008, 07:13 am »

Out of curiosity, I have started to try different tubes in the Isabella. I use the mapleshade tube anchors and like all tubes better with them.
Compared to the stock tubes,
- Matshushita E88CC 6922 Japan - MINT NOS NIB Mullard Tooling seem to resolve a bit better. The midrange may be sounding slightly thinner.
- Tungsram (not sure what variety, they are labeled in red letters) have more air and dimensionality (maybe even more than "realistic"?), less "slam" than the others. Bass has less pressure, but more definition. I hear more details, complex passages seem to be resolved better. Very seducing sound. This is the best tube of the three in my opinion.
I have ordered:
- Tesla with the 32 factory code
- and Siemens gold pin (not quite sure what year etc).

Vinnie informed me that the "holy grail" in 6922 tubes are the Amperex pinched waist tubes? However, they seem very hard to get at all. Based on past sales, the price of a pair is from 400$ to 800$

BTW, a highly recommended upgrade to the Isabella are the Boston Audio Tuneblocks (I have the XT version with Tungsten Carbide bearing). The sound becomes more stable and transparent. Those improvements are not subtle in my opinion.

lonewolfny42 · « **Reply #1 on:** 5 Sep 2008, 07:40 am »

You might check out some NOS Mullards......

Vinnie R. · « **Reply #2 on:** 5 Sep 2008, 02:44 pm »

Hi 6rs,

Excellent post!

This is a great thread to share your Isabella tube rolling experiences.

This might be helpful for those looking for a great sounding set of tubes:

The other night I visited Steve at North Lake Audio (20 minutes South of RWA, in Hamden, CT).

He has a small stash of Amperex 7308s (get 'em while there are HOT!

):

- Amperex USN-CEP (military grade), gold pins, 7308 tubes.

- Matched pairs (he has a very nice tube tester tha the showed me and matched them all)

- All are 1965 production, white letter, U.S.A. (Amperex New York)
manufacturer (Philips) Amperex factory date code: VR5 *5D

- Price: $120.00 per pair

- Contact: [email protected]

We tried them in the Isabella and they are magic and well worth the asking price, IMO! (especially since I know Steve is a very reputable source and carefully tests every tube to make sure they are matched and perform like new). The midrange is amazing on these, and they still have the bass control and "punch" as the stock JJs. The top end is very sweet, airy, and extended on these as well...

NOTE: I have NO business affiliation with North Lake Audio, but Steve and I have become friends. We enjoy listening in his awesome room, going out to New Haven, CT for great food and live music, etc. I recommend my Isabella customers to Steve if they are looking to tube roll without the risk of getting ripped off with bad tubes that do not perform as they should and are not really "matched" or performing "like new" as advertised.

Thanks again,

Vinnie

PS: At the last NYAR, Levi swapped in some NOS tubes in our Isabella. They sounded beautiful as well! Levi, can you remind me which tubes they were? (Amperex?) Thanks!

Afterimage · « **Reply #3 on:** 12 Sep 2008, 01:40 am »

Thanks for the tip on the tubes from North Lake Audio. I have a pair on the way and will try and post my impressions later on.

6rs · « **Reply #4 on:** 17 Sep 2008, 06:45 pm »

Hi
An update on my recent tube rolling experiments.
I got the Tesla gold-pins with the 32 factory code, and the Siemens goldpins (supposely from the sixties).
The Tesla are nicely balanced and do everything quite well: Have nice bass, slam, voices are seductive. They may not be top in each category, for example the Tungsram are more airy, have better texture in the bass, nevertheless they represent an excellent value.
The Siemens are remarkable in their way. They offer high resolution and provide a lot of texture to each instrument and/or sound. Bass is solid too. They do not sound harsh, but in a way lack a bit of "magic" or intimacy. However, in their way they are very nice, especially for classical music.
While these observations are reproducible with my individual tube pairs (I used the same music for the comparisons), I do not know how representative they are for a whole brand or production batch.
I am looking forward to the Amperex 7308.

Vinnie R. · « **Reply #5 on:** 18 Sep 2008, 12:45 am »

Quote from: 6rs on 17 Sep 2008, 06:45 pm

Hi
An update on my recent tube rolling experiments.
I got the Tesla gold-pins with the 32 factory code, and the Siemens goldpins (supposely from the sixties).
The Tesla are nicely balanced and do everything quite well: Have nice bass, slam, voices are seductive. They may not be top in each category, for example the Tungsram are more airy, have better texture in the bass, nevertheless they represent an excellent value.
The Siemens are remarkable in their way. They offer high resolution and provide a lot of texture to each instrument and/or sound. Bass is solid too. They do not sound harsh, but in a way lack a bit of "magic" or intimacy. However, in their way they are very nice, especially for classical music.
While these observations are reproducible with my individual tube pairs (I used the same music for the comparisons), I do not know how representative they are for a whole brand or production batch.
I am looking forward to the Amperex 7308.

Hi 6rs,

Thanks for the feedback on the Teslas. I've tried a pair of Telsa PCC88s, and while they probably are not the same model Tesla that you are using, they seemed to have the sonic characteristics that you mention (well-balanced sound that does a lot of things very well).

Quote

I do not know how representative they are for a whole brand or production batch.

This is an excellent point! Different production lots of tubes from different years - there is quite a bit of variance with tubes. Also, unless you know you are getting a good pair of tubes - low usage, matched (or close to it!), up to specs, etc. - one has to be careful not to say "this make/model/year" sucks" when it can be a bum tube(s)

I guess this is why people add "YMMV" to their posts

Still - it is very helpful and appreciated for everyone to share your findings. I'll be posting some of my findings soon....

Vinnie

6rs · « **Reply #6 on:** 18 Sep 2008, 06:36 am »

Quote

Also, unless you know you are getting a good pair of tubes - low usage, matched (or close to it!), up to specs, etc.

Actually I forgot to mention that all the tube pairs came with measurements and were matched pairs. However, I have no means to double-check those claims, but have no reason for mistrust either.

BTW, a bit off-topic: I have exchanged the inductor in the mid/bass driver section of the Xover (ATC SCM20) from Alphacore to Duelund. I had doubts about that move and was prepared to regret spending the cash on the Duelunds. There is a substantial fraction of people (including ATC itself) that would think such a part swap is ridiculous and improvements are not to be expected and, if perceived, solely due to "placebo effect". However, my ears and brain tell me otherwise: the sound improvement was substantial - residual grain in female voices is gone, sound is more effortless.

Afterimage · « **Reply #7 on:** 18 Sep 2008, 05:42 pm »

I just recieved the Amperex 7308. I only got a chance to spend about 15 minutes and only one peice of music with them so far. I listened to Ammie Mann and all I will to say at this point is it is a huge improvement over the stock tubes in my system. I will try and post more details after I get some more time.

carsten_chr · « **Reply #8 on:** 20 Sep 2008, 10:12 pm »

Best tube ever (sorry to say) are the most expensive Siemens Cca from the late 50's !.......

I have tried almost all tubes in the ECC88 family, and must say that most are wast of valuable time compared to the Siemens Cca !......

If you want to check this wonderful tube out; then please be aware to have the right stuff (huge difference) !......

6rs · « **Reply #9 on:** 21 Sep 2008, 05:51 am »

Quote from: carsten_chr on 20 Sep 2008, 10:12 pm

Best tube ever (sorry to say) are the most expensive Siemens Cca from the late 50's !.......

I have tried almost all tubes in the ECC88 family, and must say that most are wast of valuable time compared to the Siemens Cca !......

If you want to check this wonderful tube out; then please be aware to have the right stuff (huge difference) !......

Did you also try a Telefunken CCa? When you say "the right stuff", you refer to forgeries, or Siemens CCa from later (70s)? What are the diagnostic traits of a Siemens CCa from the late 50s?
Thanks!

carsten_chr · « **Reply #10 on:** 21 Sep 2008, 06:43 am »

Quote from: 6rs on 21 Sep 2008, 05:51 am

Quote from: carsten_chr on 20 Sep 2008, 10:12 pm
Best tube ever (sorry to say) are the most expensive Siemens Cca from the late 50's !.......

I have tried almost all tubes in the ECC88 family, and must say that most are wast of valuable time compared to the Siemens Cca !......

If you want to check this wonderful tube out; then please be aware to have the right stuff (huge difference) !......

Did you also try a Telefunken CCa? When you say "the right stuff", you refer to forgeries, or Siemens CCa from later (70s)? What are the diagnostic traits of a Siemens CCa from the late 50s?
Thanks!

Yes, I have tried the Telefunken Cca's too - also a very, very good sounding tube too !.......

But the Siemens Cca's (from late 50's to first 60's) just have a touch more of air, 3D, naturalness - just sound right !.......

Compared to the Siemens Cca's all new tubes that I know of, sounds mechanical (almost didital) and un-natural !.......

I have tried the Siemens Cca's from the 70's too - better than new tubes in general, but nothing compared to the real stuff !......

So it is - unfortunately !.....

Vinnie R. · « **Reply #11 on:** 22 Sep 2008, 06:05 pm »

Quote from: Afterimage on 18 Sep 2008, 05:42 pm

I just recieved the Amperex 7308. I only got a chance to spend about 15 minutes and only one peice of music with them so far. I listened to Ammie Mann and all I will to say at this point is it is a huge improvement over the stock tubes in my system. I will try and post more details after I get some more time.

Hi Afterimage,

Besides the Amperex "pinched waist" tubes that are very rare and too expensive, the Amperex 7308s that Steve at North Lake Audio is selling are my favorite so far! They have such an effortless sound and amazing tonal balance - I love 'em!

Steve also told me that he came across a small batch of Amperex 6DJ8 "orange globe logo" made in Holland tubes. I just picked up a pair from him and will be testing them soon. He mentioned that they'll be less expensive (I think he said $70/pair) and he is in the process of carefully testing them with his tube tester and matching them.

Quote

But the Siemens Cca's (from late 50's to first 60's) just have a touch more of air, 3D, naturalness - just sound right !.......

Hi Carsten,

Thanks for posting. Do yo have these Siemens Cca's to try with the Isabella? I hope to be able to find a pair one day and try...

I have to admit, this tube rolling thing is a lot of fun and a little addicting! aa

Vinnie

carsten_chr · « **Reply #12 on:** 23 Sep 2008, 07:43 pm »

Hi Vinnie !.......

As you might guess tube rolling are not new to me !.......

During the last 12 years or so I have had (and still have) a lot of tube gear (pre-amp's, power-amp's and DAC's) - in fact I have had so much tube based equipment that I found it absolutely necessary to have my own private tube tester !........

Answer to your question:

Yes, the Siemens Cca's are placed in the socket's of my Isabella - a huge difference !.......

I know the Amperex tubes too - unfortunately I have to tell you, that they don't even come close to the Cca's - sorry !......

You have to hear the real stuff one day !......

moonman · « **Reply #13 on:** 23 Sep 2008, 11:22 pm »

Hi Carsten,

Steve here, from North Lake Audio. I've had all of the 6DJ8/6922/7308 types, too. I had the Siemens CCA and I prefer the Amperex pinched waist over them. There are several versions of the CCA and the best are, as often the case, the earliest D-getter variety. These go for in excess of $300 a pair, the last I checked.

I think another consideration is the plate voltage (and other parameters) at which the component designer is running the tube. This is probably one of the reasons why the same tube type may not be preferable in a different component.

Another example was ARC preamp owners insisting on using the Amperex Bugle Boys in them. They claimed they were the best-sounding in that piece (e.g., ARC SP10).

All that being said, I would also be interested in hearing the CCA in the Isabella. Whatever the outcome, I heard the Amperex 7308 gold pin in the Isabella in my system, and it sounded very good....a major improvement over the stock JJ tubes.

Cost is a consideration here, of course. People can spend $600 on a pair of Amperex pinched waist tubes if they like. However, I think there are probably a lot of people who are happier spending a lot less for a major improvement over the stock JJ tubes (although they are probably the best of new production).

Regards,
Steve
North Lake Audio

carsten_chr · « **Reply #14 on:** 24 Sep 2008, 05:19 am »

Hi Steve !......

You may have a point by your argument !......

Unfortunately the case with the Siemens Cca's are that most people buying this tube get's cheated big time !....... They are NOT getting what they are told by the seller !......

I have been doing Simens Cca's right from the start of my "tube life", and can tell real clear that I (when I was not that experienced) was cheated several times too !.......

When tou have a Siemens Cca it's In fact very hard to verify if it's the right stuff - but still there are some characteristics !......

If you have some Siemens Cca's and you don't know if they are the right stuff, then please feel free to sent me some detailed pics of each of them. I then study the tubes, and tell you what you have !........

The differences between the different types are unbelieveble !.....

6rs · « **Reply #15 on:** 24 Sep 2008, 07:25 am »

Quote from: carsten_chr on 24 Sep 2008, 05:19 am

If you have some Siemens Cca's and you don't know if they are the right stuff, then please feel free to sent me some detailed pics of each of them. I then study the tubes, and tell you what you have !........

Well, just bought some off ebay. Are they the real thing?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150295483978&ssPageName=ADME:B:EOIBSA:GB:1123#ebayphotohosting
Thanks!

carsten_chr · « **Reply #16 on:** 24 Sep 2008, 09:10 pm »

Hi 6RS !.......

Not bad at all !......

I may need more pics to be 100 % sure !.......

But here it is:

The left tube are the right stuff, and the right tube are just a few years newer - both real good stuff !.......

You have to ensure that both of the tubes are measuring 100 %, and that none of them have any problems with noise and microphonics !.......

Then you are on the road to heaven !.......

Please post your impressions here in this forum - I'm quite sure you'll be amazed by the sound from this outstanding tubes !....

6rs · « **Reply #17 on:** 25 Sep 2008, 10:14 am »

Thanks Carsten, for your expertise

Quote from: carsten_chr on 24 Sep 2008, 09:10 pm

You have to ensure that both of the tubes are measuring 100 %, and that none of them have any problems with noise and microphonics !.......

Yes, this is the risk I have taken. On the other hand, the price was ok. Since I have no tube tester, I will have to rely on my ears to detect any potential problems.
I will compare to the Amperex 7308 from Steve (they will provide a positive control of a matched pair of nice tubes in good health), and the pair of Siemens e88cc (from the sixties) I got off ebay (they measured >100%, according to seller).
Thanks!

Vinnie R. · « **Reply #18 on:** 25 Sep 2008, 12:56 pm »

Hi 6rs,

Nice find! aa

Please keep us posted!

Thanks,

Vinnie

Afterimage · « **Reply #19 on:** 27 Sep 2008, 01:39 pm »

Quote from: Afterimage on 18 Sep 2008, 05:42 pm

I just recieved the Amperex 7308. I only got a chance to spend about 15 minutes and only one peice of music with them so far. I listened to Ammie Mann and all I will to say at this point is it is a huge improvement over the stock tubes in my system. I will try and post more details after I get some more time.

A pipe burst and my basement flooded. All of my stuff is okay, but I am out of the game until I can get the drywallers and new carpet down.