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

RPM123 · « **Reply #60 on:** 21 Dec 2015, 04:23 pm »

Quote from: jimbones on 21 Dec 2015, 03:42 pm

Im using RCA grey glass in my ls100. Love it. I am considering Black Treasure Cv181z and not sure if I will regret it

Hi,

Thought you might be interested in seeing this email from Rachel of Grant Fidelity after I inquired about the differences between the tubes: "The CV181-Tii are special selected for very low noise for high end preamp and phonostages. CV181-Z wasn't screened to that extent. If you are considering these tubes for tube amp driver stage before power output tubes, CV181-Z at $199 is perfectly fine." And FYI - Grant Fidelity does stand behind the tubes it sells.

dminches · « **Reply #61 on:** 21 Dec 2015, 04:33 pm »

Stick with old production tubes. They are nicer and cheaper.

Try a pair of Sylvania WGTA brown base. Very nice tube.

jimbones · « **Reply #62 on:** 21 Dec 2015, 04:34 pm »

Thanks RPM. I read that the cv181z is more laid back that the TII. So I am thinking it will sound more like the RCA than the TII. I just have to make sure they will fit!

borism · « **Reply #63 on:** 21 Dec 2015, 06:22 pm »

I don't have experience with a Modwright LS100 but my Atma-Sphere MP3 also uses two 6SN7 tubes. While I tried Psvane CV181 T1 ultimately I preferred NOS tubes - Ken-Rad VT231 black bottle and Brimar CV1988. The Psvane, however, is very good.

dminches · « **Reply #64 on:** 21 Dec 2015, 09:12 pm »

The Ken Rads are nice. The are little heavy in the bass and a little light in the treble but they are really nice tubes. The CV1988s are sweet too.

jimbones · « **Reply #65 on:** 21 Dec 2015, 10:54 pm »

As far as NOS Im thinking CBS-hytron, RCA or maybe a Sylvania. The problem with NOS is you have to make sure you get the right model and hope that it has sufficient life left. (Technically they are new but….

)

borism · « **Reply #66 on:** 21 Dec 2015, 11:08 pm »

Working with reputable dealers like Brent Jessee, Paul Lindeman or Kevin Deal (Upscale Audio) helps regarding any NOS worries. They test the tubes and usually stand behind them.

JackD · « **Reply #67 on:** 21 Dec 2015, 11:09 pm »

As the LS-100 only uses half the tube at a time they are going to last twice as long when you switch positions. A simple way to get the right model is to call and talk to someone like Andy Bowman or Brent Jessee and tell them what you are looking for. The few dollars extra from them will save you money in the long run. Also read the reviews online as to the general sound of the different tube families. I would trust the longevity of any of the NOS tubes over any of the new Chinese ones. Plus even the better NOS ones save the "flavors of the month" are cheaper than the Chinese tubes. The Hytron's are probably the most neutral of the ones you listed in my system.

jimbones · « **Reply #68 on:** 21 Dec 2015, 11:47 pm »

Quote from: borism on 21 Dec 2015, 11:08 pm

Working with reputable dealers like Brent Jessee, Paul Lindeman or Kevin Deal (Upscale Audio) helps regarding any NOS worries. They test the tubes and usually stand behind them.

Yes I have purchased from Brent Jessee, nice guy to do business with.I don't know Paul.

toddc2 · « **Reply #69 on:** 11 Feb 2016, 01:56 pm »

Quote from: jimbones on 21 Dec 2015, 11:47 pm

Yes I have purchased from Brent Jessee, nice guy to do business with.I don't know Paul.

+1 on Brent, really a very nice guy to work with who stands behind his product. I know this first-hand as I'm really struggling to get a quiet pair of 6SN7's for my LS100:

RCA VT-231 (Pair 1) from Brent. One tube was excellent, the other microphonic (as posted earlier on this thread). Replacement tube was noise tested but was noisy in the LS100. Brent was really great working with me on this.

Sylvania VT-231 (Pair 2) from Audiogon. Again one tube was excellent and one is microphonic. The bad tube settled down after a couple of hours of warmup so it's tolerable but not great (who wants to wait 2 hours every time they power up?). Very good sonics, very transparent, but lacking bass slam.

RCA 5692 Red Base (Pair 3) from CanuckAudioMart. Again one tube was excellent and the other noisy. By far the best sounding tubes I have tried in my LS100. The noise floor of the questionable tube is about the same as the background noise from a needle in the groove so this is tolerable for listening to vinyl but completely unacceptable for digital.

For those wondering if I have a bad channel in my preamp, I would say no for two reasons: 1) the symptoms follow the tube and 2) the crappy sounding Russian current production tubes that came with my LS100 are dead quiet.

So the struggle continues...

I will try Andy when he gets back to the office. I might also consider a new production set of Sophia Electrics or BT's...

Todd

SoCalWJS · « **Reply #70 on:** 11 Feb 2016, 04:13 pm »

I saw the new post on this thread and went back to read the old comments to refresh my memory on what's been said and done.

Glad I did.

I recently moved and finally got the main system setup in the new house (that's a topic unto itself - not a great room - too small, but boy are the acoustics different. Much work ahead), BUT...

I forgot to reverse the polarity

. Corrected now, but my main source is back at the factory for repairs.

JackD · « **Reply #71 on:** 11 Feb 2016, 10:39 pm »

Todd

I had to go through three RCA VT-231's to get two good ones and can be an issue with the military tubes sometimes is that were graded and selected for uses other than audio. I understand that Andy does more actual "in gear" testing and sells in grades based on intended use. Also might want to take a look at Tubemaze on Ebay as he gear tests to in addition to a tube tester.

toddc2 · « **Reply #72 on:** 12 Feb 2016, 01:23 am »

Quote from: JackD on 11 Feb 2016, 10:39 pm

Todd

I had to go through three RCA VT-231's to get two good ones and can be an issue with the military tubes sometimes is that were graded and selected for uses other than audio. I understand that Andy does more actual "in gear" testing and sells in grades based on intended use. Also might want to take a look at Tubemaze on Ebay as he gear tests to in addition to a tube tester.

Thanks Jack! I really liked the RCA VT-231's but after a 1 for 3 experience they went back to Brent. I'm going to send my Sylvania VT-231's to Andy to see if they can be salvaged, maybe he can match the good one. The RCA Red Base's sound fantastic in my system (other than the noise in one tube). I'll probably buck up and buy a really quiet pair from Andy while he's testing my Sylvania's. Thanks for the tip on Tubemaze, I'll check them out.

Todd

JackD · « **Reply #73 on:** 12 Feb 2016, 01:38 am »

Randy

I've got four of the RCA Jan-6SN7GT's with "smoked glass" from the same era as the VT-231's and half of them were two noisy for the LS-100, but worked fine as input tubes on two different tube amps. They do have that "liquid" midrange and very good bass. The Sylvania's are a little drier and not quite as prominent in the bass in my setup. The most "neutral" tube I have used in the LS-100 is the white label Hytron 6SN7GT followed by Raytheon VT-231's. Andy lists mostly RCA and Sylvania on his website, but I would guess he has most everything and he grades them from Line to MC Phono. I tried a bunch before deciding on the Hytrons for now.

Manolo · « **Reply #74 on:** 13 Feb 2016, 12:43 pm »

Read this thread with interest. I do not use any Modwright equipment but I do have a Supratek preamp. which also uses 6sn7's and is also tube rectified. After some tube rolling with 6sn7's which include BT,-very musical and smooth, but lasted only 3 months, had to return them-, Sylvanias short bottles -nothing special-, RCA's grey glass very smooth and musical, kind of floppy bass, RCA gtb kind of the same, Sylvania 5692's black base, very rare, the real thing w/ additional rods and micas, -kind of cold sounding, don't think are really suited for this preamp. I really like a Raytheon short bottle -it is very musical dynamic and balanced, some microphone- Sophia Electric -having a lot of fun with these, much better experience than w/ the BT's. And lastly, -heresy!- I always come back to my trusty EH's and TS's reissues...... Across the board, they seem to have all the good qualities of all the above tubes. I can pick up things other tubes do better but these are the most balanced. And why? I strongly believe that Mick Maloney, Supratek's designer, voiced his designs with modern manufactured Russian 6sn7's and both the EH's and TS's meet this requirement. In private communications he has hinted to this. I guess Mr. Wright has his favorite 6sn7 tube to voice his designs but maybe it is not the most expensive and most "NOS" tube out there, would be good to find out. This has been my experience with my preamplifier so far and my 2 cents. And, for the rectifier I am using the Bendix 6106- have to get another GZ34 though my Mullard is not well lately.....another story

toddc2 · « **Reply #75 on:** 13 Feb 2016, 01:56 pm »

Quote from: Manolo on 13 Feb 2016, 12:43 pm

Read this thread with interest. I do not use any Modwright equipment but I do have a Supratek preamp. which also uses 6sn7's and is also tube rectified. After some tube rolling with 6sn7's which include BT,-very musical and smooth, but lasted only 3 months, had to return them-, Sylvanias short bottles -nothing special-, RCA's grey glass very smooth and musical, kind of floppy bass, RCA gtb kind of the same, Sylvania 5692's black base, very rare, the real thing w/ additional rods and micas, -kind of cold sounding, don't think are really suited for this preamp. I really like a Raytheon short bottle -it is very musical dynamic and balanced, some microphone- Sophia Electric -having a lot of fun with these, much better experience than w/ the BT's. And lastly, -heresy!- I always come back to my trusty EH's and TS's reissues...... Across the board, they seem to have all the good qualities of all the above tubes. I can pick up things other tubes do better but these are the most balanced. And why? I strongly believe that Mick Maloney, Supratek's designer, voiced his designs with modern manufactured Russian 6sn7's and both the EH's and TS's meet this requirement. In private communications he has hinted to this. I guess Mr. Wright has his favorite 6sn7 tube to voice his designs but maybe it is not the most expensive and most "NOS" tube out there, would be good to find out. This has been my experience with my preamplifier so far and my 2 cents. And, for the rectifier I am using the Bendix 6106- have to get another GZ34 though my Mullard is not well lately.....another story

I picked up my LS100 used so I'm not sure what tubes Dan ships with. I know he recommends the Sophia Electric as an upgrade.

The previous owner of my LS100 installed a Russian Mullard rectifier and Russian TS 6SN7's. The new production TS sound flat and lifeless. The only redeeming quality of these tubes is that they are quiet.

The NOS tubes I have been trying all sound better than the TS, at the expense of noise and/or microphonics. i will keep searching for the right tubes but I am getting a little irritated at how difficult it has been to find something quiet. Is it the tubes or the preamp?

Manolo · « **Reply #76 on:** 13 Feb 2016, 05:27 pm »

And, one gets tired of the break in hours for each new tube......

dminches · « **Reply #77 on:** 13 Feb 2016, 06:12 pm »

When I had my LS-100 I used number of older issue tubes and never had an issue with noise or microphonics. I finally settled on a pair of TS BGRPs which sounded better than anything else I tried. They are expensive ($300 or more) but well worth it for the unit which sounds great.

toddc2 · « **Reply #78 on:** 13 Feb 2016, 10:57 pm »

I spent all afternoon working on this. The tube pins are all polished and treated with Deoxit Gold. I swapped power cords. I swapped from XLR interconnects to RCA. I swapped rectifiers. The pin polishing was the only thing that helped, as now both channels are about the same wrt noise. However, the noise can still be easily heard from my listening position. It's not as loud as before but still annoying.

RPM123 · « **Reply #79 on:** 14 Feb 2016, 03:09 am »

I have the LS100 and was using a pair of Russian 1578's for about 3 months when one of the tubes started making sputtering sounds and loud pops, so I immediately turned of the preamp. I was quite bummed, since I really liked those tubes! I am now using a set of East German RFT 6SN7's with ceramic spacers (no micas) and grey plates for 2 months now and no issues thus far. They were only made for about 3-4 years in the early 50's and I find them to be every bit as good as the 1578's and perhaps better in some areas. I tried Psvanes CV181 II's and one of them developed an intermittent high pitched but very low level tone (RFI?). Grant Fidelity replaced them with brand new tubes even though they were past the 90 day warranty. Very nice tubes, but a bit "lush" sounding for my tastes. I have never experienced any microphonic issues in the above mentioned tubes and they were all very quiet, until the problems arose.

I also have a pair of MELZ 6H8C's and one channel was a bit noisey (hiss) and I replaced them with the 1578's. After one of those went bad, I put the MELZ back in and strangely enough, the tube noise was largely reduced. Maybe it just needed a "rest". I guess that is just part of the trials and tribulations of dealing with tubes, especially NOS.

With apologies to Henry Wadsworth Longfellow:

There was a little tube,
Which had a little filament,
Right in the middle of its' electrodes.
When it was good,
It sounded very good indeed,
But when when it went bad it was horrid.