Let's talk about Tube Rolling in the Modwright LS100 Pre

nnck · « **on:** 3 Mar 2011, 06:34 pm »

Wanted to start a thread to talk about some specific tubes people may have tried in place of the stock tubes that come with the Modwright LS100 Preamp.

For me specifically, I would be looking for something that would help fill out the sound mostly at the bottom end and just a bigger, fuller sound in general. At the same time, I dont want to lose the detail and the wide soundstage that I already have. And I am interested in getting as much holographic sound as possible (Dont know if any of these wants are contrary to one another).

But really anything you've tried please just post here and give some info about how it has worked out in your system.

BTW, please include in this discussion all the tubes found in this preamp(5AR4/GZ34 Rectifier, 6SN7 Drivers and also the 12AX7 and 12AU7 found in the phono stage).

nnck · « **Reply #1 on:** 30 Mar 2011, 07:01 pm »

Hasn't anyone successfully rolled out tubes in the LS100 preamp?

How did it work out and What were you impressions?

dminches · « **Reply #2 on:** 31 Mar 2011, 03:00 am »

I have been using 2 Tung Sol 6SN7 black glass round plates and a Mullard GZ34. I have enjoyed the sound so much that I haven't tried anything else.

nnck · « **Reply #3 on:** 31 Mar 2011, 03:46 am »

Quote from: dminches on 31 Mar 2011, 03:00 am

I have been using 2 Tung Sol 6SN7 black glass round plates and a Mullard GZ34. I have enjoyed the sound so much that I haven't tried anything else.

dminches-
Did you feel these tubes changed the sound in some way vs. the stock tubes that came with the LS100? In what way, and which tubes mattered more?

Sorry, I'm a tube newbie and get confused by this stuff easily. Are these tubes you replaced them with new production tubes or NOS? Where can you find them? Any links I can look at?

Thanks a bunch.

dminches · « **Reply #4 on:** 31 Mar 2011, 12:06 pm »

I did not run the LS-100 with stock tubes. I had the other NOS on hand so I immediately threw them in. It is really up to you to decide which sound you prefer. There is no "stock" answer.

Regarding buying NOS tubes, I would look on ebay (carefully), audiogon and some of the on line sellers like Tube World and Audio Tubes.

jriggy · « **Reply #5 on:** 31 Mar 2011, 02:22 pm »

I have tried the Black Treasure CV181-Z and the Tung-Sol black glass, round plates as well... I think these two, very well may be the top performers - taking into account other reviews of the tubes and having other 6sn7 that i have used in other gear.
That is a broad statement to call the two set the 'best' but they both have great repartitions to back em up as well.

The BT's are holographic, detailed, well extended and fleshed out. Not as 'abrupt' (for lack of a better word) thant the stock tubes. real solid top to bottom new stock tubes.

the TS rp's are much more organic and rounder. More analog sounding to me. What I do love about them is the air and spaciousness they add. Very holographic, wide, yet a bit diffused (still image well though). Maybe that is what is adding to the spaciousness... Great organic and euphoric sound but still hits nicely used in the LS 100

You could try tons of 6sn7 from reading characteristics of them or you could skip to the two that I find to be the best

It really all depends on what you want to get out of the pre. Bear in mind that your lack of fullness or bass could be your room sucking out the sound or an issue elsewhere.

BTW the rectifier is a Mullard Blackburn GZ34... If the signal tubes are the flavor, then the rectifier is the heart of the unit. Got great results adding a Blackburn. Just seemed to bring all the positives together even more.

nnck · « **Reply #6 on:** 31 Mar 2011, 03:48 pm »

Quote from: jriggy on 31 Mar 2011, 02:22 pm

You could try tons of 6sn7 from reading characteristics of them or you could skip to the two that I find to be the best

Well given my complete lack of experience in this area, I am going to have to go by recommendations I hear from folks like you on these sorts of forums.

Just doing general searches online or on Ebay makes me a bit nervous, as there are just SO MANY tubes with SO MANY similar looks and names that it all gets a bit confusing. And then you start hearing about how many of them are re-branded and it gets even more difficult... It seems that this could be an area where look-alikes and couterfeits might be common (could be wrong).

But thank you both for your help so far. A couple additional questions. It appears that the one source I know of for the Shuguang Black Treasure 6SN7 (CV181-Z) has been out of stock for the Grade A variety for quite some time. Do you folks know of multiple sources for these Black Treasure tubes?

And how about the Tung-Sol black glass round plates? These are NOS, correct? So finding them might be more difficult. Can you recommend sources for these that wont break the bank? As I said, I dont quite trust my instincts enough to use Ebay yet - if I could find them from other online sellers with a good reputation, maybe it would be better for me right now.

jriggy- the same sort of questions would pertain to the Mullard Blackburn GZ34 you mention. I'm guessing this is another NOS. Where is a good source and approx how much might they go for?

Audioclyde · « **Reply #7 on:** 9 Apr 2011, 02:09 pm »

I've been really, really enjoying my LS100 for a couple of months now. I've rolled quite a few 6sn7 family tubes in it; great results with the usual TS roundplates (though my pair is getting somewhat tired I suspect), Brimar orange label, Mullard ecc33's and RCA redbase 5692's. My amp also uses a pair of 6sn7's as drivers, so I have a nice stock of this family to play with.

I've been running a fat base Mullard Blackburn gz34 as the rectifier for quite some time. Last night I popped the hood and on a whim rolled in my Mullard cv378 High Wycombe that was so good in the MW Transporter--the down side of course is that the cover can't go back on the LS100 with this rectifier in it....BUT I'm not sure I can go back to another rectifier--wow, its really, really good. Don't know how to describe the change specifically, things just seem more musical, natural. I thought my system was already doing a great job of making vocals sound natural, but with the rectifier change things have gotten spooky realistic!

Randy

dminches · « **Reply #8 on:** 9 Apr 2011, 03:37 pm »

Did you confirm with Dan that the CV378 could be used with the LS-100? I thought it wasn't a direct replacement for a GZ34.

JG2 · « **Reply #9 on:** 9 Apr 2011, 08:59 pm »

I believe the same PS circuit is in the LS100 as is in the outboard PS for players so the HW CV378 should work fine, Randy!

Audioclyde · « **Reply #10 on:** 9 Apr 2011, 09:11 pm »

Pretty sure I've read somewhere that 5u4 & 5u4gb is fine, as I think the cv378 is pretty similar.

JG2 · « **Reply #11 on:** 9 Apr 2011, 09:54 pm »

The HW CV378 is (I believe) a GZ37.

That will be OK in this application.

Audioclyde · « **Reply #12 on:** 9 Apr 2011, 10:19 pm »

JG, you are correct.

NutBuster · « **Reply #13 on:** 21 Sep 2011, 07:28 pm »

Has anyone matched up Ken-Rad Black Glass 6SN7's w/a Holland GZ34?

rlmacklin · « **Reply #14 on:** 26 Sep 2011, 06:45 pm »

Received my LS100 July 26th, so 2 months old today.

I rotated in my 1957 metal base Philips Miniwatt GZ34/5AR4 rectifier
(previously in my SWL9.0 Signature) and inserted 2 Psvane CV181-T
(similar to Shuguang Black Treasure CV181-Z, but per Rachel of Grant Fidelity:
"There is no difference in quality control, testing or specs. They are
same model tubes but T is tweaked for slightly more high frequency.")

I have never run my LS100 with the stock tubes.

After two months of break-in/burn-in, the Psvane CV181-Ts sound similar to me as "jriggy" described the BT CV181-Z :

" The BT's are holographic, detailed, well extended and fleshed out."

jriggy contrasted CV181-Z with the TungSol round plates:

"the TS rp's are much more organic and rounder. More analog sounding to me. What I do love about them is the air and spaciousness they add. Very holographic, wide, yet a bit diffused (still image well though). Maybe that is what is adding to the spaciousness... Great organic and euphoric sound but still hits nicely used in the LS 100"

In preparation for upcoming receipt of Modwright tube modified 2-channel and SS mod on remaining multi-channel Oppo 95 (with Bybee rail mod on each DAC and Truth Umbilical), I received a new NOS 1957 metal base Philips Miniwatt GZ34/5AR4 rectifier and 2 of the Sophia Electric 6SN7 on Friday and installed these in the LS100 for break-in/burn-in (went through the LS100 case disassembly, tube rolling, and assembling the case and re-inserting in system and reconnecting the ICs). Same TelWire PC used on LS100.

Source is currently Oppo 83SE with Modwright full SS 2-channel and SS multi-channel mods.

Indeed the Sophia Electric started with a slight upward tilt in frequency response curve, but right out of the box displayed increased resolution over the CV181-T at all frequencies [reference the Steve Davis Project "Quality of Silence" stereo SACD] and did not sound at all edgy or harsh to me on any material played [primary reference test for this aspect was SACD of Mozart Horn Concertos with Alan Civil on horn, with Neville Marriner conducting the Academy of St. Martin-in-the-Fields (stereo layer)].

After two days, the Sophia Electrics are clearly the more neutral and linear and resolving tube to my ears - and hence the "keepers." The sonics match descriptions by Ern Dog in the Oppo tube rolling thread here in the Modwright Circle on Audio Circle.
The slight upward tilt is reducing.

So when the modded Oppo 95 arrives, I may place the 2 CV181-Ts atop it ...
if I haven't received 2 more Sophia Electric 6SN7s by then !!!

(I plan to keep the Psvane Cv181-Ts as higher level "backups" than the stock tubes and
I will definitely run the competition again between them and the Sophias on the Modwright Oppo 95.)

mraudio · « **Reply #15 on:** 26 Sep 2011, 10:53 pm »

I'll add my 2 cents worth. I've had my LS100 for over 6 months now and have both the original BT tubes and the Sophias. I am using a Mullard GZ34/5AR4, (Blackburn) as the rectifier.

Each pair need a massive amount of burn-in/break-in. Grant Fidelity recommends 150-300 hours for the BTs. I have over 500 hours on each pair.

I find the BTs to be my "keeper" tube. In my system and for my tastes they throw a wider, deeper soundstage and are smoother and more open than the Sophias. I agree that the Sophias are "a tad" more neutral, linear and have more detail, but that's not what I am looking for. I wanted a smoother, more open, more romantic sound and found that in the BTs. Had I started with the Sophias, (I didn't, I started with the BTs), I might have just stopped.

Bottom line, they are both excellent tubes and really need to be tried in one's system to match personal tastes and preferences. You really can't go wrong with either.

SoCalWJS · « **Reply #16 on:** 14 Dec 2011, 12:43 am »

OK. went ahead and pulled the trigger and ordered the Black Treasures. Hopefully here tomorrow or the next day.

Can't make up my mind on the rectifier though. Hard to find the Mullard and I'm a bit paranoid about some of the ebay sellers. What other options are recommended these days?

Who's having good luck with what??????

dminches · « **Reply #17 on:** 14 Dec 2011, 01:50 am »

A less expensive tube would be a Tung sol 5U4G. I believe you can use it instead of a GZ34.

wilsynet · « **Reply #18 on:** 14 Dec 2011, 02:27 pm »

There are three Mullard GZ34 rectifier tubes on Audiogon right now. If you want an impeccable source, consider Andy at Vintage Tube Services, Brent Jesse, etc.

I really like Andy. You have to be patient and you have to phone him, but he's trustworthy and if I recall, he also has a return policy.

SoCalWJS · « **Reply #19 on:** 14 Dec 2011, 03:39 pm »

Quote from: wilsynet on 14 Dec 2011, 02:27 pm

There are three Mullard GZ34 rectifier tubes on Audiogon right now. If you want an impeccable source, consider Andy at Vintage Tube Services, Brent Jesse, etc.

I really like Andy. You have to be patient and you have to phone him, but he's trustworthy and if I recall, he also has a return policy.

Thanks - I see the listings on Audiogon.
Question: What makes a "Mullard" a Mullard? One of the three listings on Audiogon is an an actual "Mullard", one is a Phillips, and the other is a Hammond. They claim to be from the U.K., and more specifically Blackburn.

Is there a real difference or not?