Modwright OPPO 105 tube rolling

rbbert said:
Nevertheless, the major tube vendors do make a point of this for (at least) the 6SN7.
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The major tube vendors make a point of what? Telling you that NOS 6SN7 tubes tend to be microphonic? If I was in the business of selling new production 6SN7 tubes, I might say the same thing. NOS audio tubes do not become microphonic with age. There is no scientific data that would back up that assertion to my knowledge. Any tube can be microphonic whether it's NOS or fresh off the production floor. Any tube whether NOS or new production can start off not being microphonic and then turn microphonic overnight. If you have been around tubes enough in your life, you know what I mean.

The good news if you use 6SN7 tubes is that they were as common as dirt when tube production was in all of its glory the world over. That means there were at least a gazillion of them made and the supply of NOS tubes is still plentiful. Stop the press! I just went to Upscale Audio's website to take a gander at what NOS 6SN7 tubes Kevin is offering and I see that Kevin is saying that quite a few of them are microphonic. Kevin does have 6SN7 tubes in the platinum category which means they are suitable for use in both line stages and phono stages and he has NOS military platinum grade Tung-Sol tubes for $120.00 each (not to be confused with current production Sovtek 6SN7 tubes that have Tung-Sol labels and Tung-Sol boxes.

Kevin also has all of the usual current production 6SN7 tubes at cheap prices which he says sound great and aren't microphonic. If I was sticking them in an Oppo (or any other digital box that primarily was used for PCM), I would probably go with the cheap Russian or Chinese tubes.
 
How do you know the Oppo is used primarily for PCM ??
One way new production tubes might be that they can be easily screened for microphonics and the "bad" tubes discarded. As far as what to put in the Oppo, I would say the best you can afford because even the most expensive are only a small fraction of the price of the unit itself and the sound can be improved significantly. Certainly better than your 'table LOL

I've had tunes in and out of my system since the early '70's.
 
You've had tunes or tubes in your system since the early 70's? :) As for how I "know" the Oppo is primarily used for PCM, it's just an educated guess. I think at this point in time that PCM playback is way more prevalent than DSD.

I agree with you that if you want the best sound possible, I would go with a premium grade NOS 6SN7 tube vice current production. And yeah, I'm sure your Oppo blows my SP-10 MKII table, SME 312S arm, and my XV-1s cartridge in the weeds.
 
Typing on an iPhone is certainly prone to mistakes :D And you should know by now my opinions on LP's...
 
Brent Jessee has a good variety of high quality NOS 6SN7 matched pairs currently (he usually sells out of these quickly, although he usually eventually finds more; that can't go on forever, though). TungSol oval plate blackglass, newer (but still quite good and much cheaper) TungSols, a variety of Sylvanias, Ken Rads, Raytheon and RCA at various price points. Also the usual assortment of UK or Dutch GZ34's (all made by Mullard) for the rectifier.
 
Got my OPPO last night. Had a quick listen tonight. Out of box with stock power cords, it sounds so so. My Marantz UD9004 was better. The Weiss Medea+ that I returned was much better. I'll give it more time. I also plan to upgrade the power cords, fuse, feet, and tubes.
 
TommyC said:
Got my OPPO last night. Had a quick listen tonight. Out of box with stock power cords, it sounds so so. My Marantz UD9004 was better. The Weiss Medea+ that I returned was much better. I'll give it more time. I also plan to upgrade the power cords, fuse, feet, and tubes.
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Glad to hear you have received it, Tommy. It won't sound anywhere near its potential with stock tubes and stock power cords. I also found with mine that it needed 120+ hours to break in and for the sound to settle down.

If you can be patient, use your stock tubes to run it in 24x7 for at least a week or two. It will go through a lot of changes. I tried to break mine in with the stock tubes (which would have been smart), but the upgraded tubes sounded so much better that I couldn't help myself, and I ended up switching them out right away, and just listening to it as it went through its changes.
 
I have 2 Crystal Cable Absolute Dream power cords ready for them. I'm still waiting on some NOS tubes.
 
With about 75 hours on the OPPO + after market power cords, it's sounding a lot better now.

Compared to the UD9004, it is clearly better. Compared to the Weiss (via memory), it is smoother, less "hard." Dynamic range, detail, and imaging is still a notch below the Weiss. But it will only get better after I get some NOS tubes, fuse, and footers. I will also give everything 500hrs before making a final impression.
 
i found the Ken-Rad VT-231 to sound quite neutral, but very microphonic in the oppo. Sophia too.
The Sylvania 6sn7 from VTS was neutral too, with very little to no microphonics. rated "MC" by Andy. my fave so far.
RCA short bottle had very little microphonics and sounded a little warmer.
 
Concerning the 6SN7 family of tubes, I have consistently found that a 6F8G (the grandfather of the family) with an adapter out performs the newer smaller bottle "GT"s. More dimensional, larger soundstage and depth. VT-99's are the military version of 6F8G's and have been graded and checked to be of a higher quality by the manufacturer.
It is claimed by some that adapters degrade the sound. In relation to this tube substitution, I have not noticed any negative effects only MUCH MUCH better sonics.
CAUTION: Only try this if you are looking to take this piece of gear to the next level.
You have been warned.
 
jadedavid said:
Concerning the 6SN7 family of tubes, I have consistently found that a 6F8G (the grandfather of the family) with an adapter out performs the newer smaller bottle "GT"s. More dimensional, larger soundstage and depth. VT-99's are the military version of 6F8G's and have been graded and checked to be of a higher quality by the manufacturer.
It is claimed by some that adapters degrade the sound. In relation to this tube substitution, I have not noticed any negative effects only MUCH MUCH better sonics.
CAUTION: Only try this if you are looking to take this piece of gear to the next level.
You have been warned.
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Do you feel this is specific to the Oppo, or any 6SN7 application? There a a few recent preamp and amp designs that use the 6SN7 (Cary, Atma-sphere, etc); if the 6F8G were really a better tube I would think those designers would have spec'd it, and without an adaptor. The same argument could be made for Modwright; why not start with that tube if it is better?
 
rbbert said:
Do you feel this is specific to the Oppo, or any 6SN7 application? There a a few recent preamp and amp designs that use the 6SN7 (Cary, Atma-sphere, etc); if the 6F8G were really a better tube I would think those designers would have spec'd it, and without an adaptor. The same argument could be made for Modwright; why not start with that tube if it is better?
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Most companies that design and build tube gear with aspirations of having lots of sales and keeping a stock of tubes for their customers are not going to design with tubes that have been out of production for years and are only available on the secondary markets like FeePay. The 6SN7/6SL7 family of tubes were a very common tube that were used around the world and they are still in production. The simple answer is you shouldn't design a new product to use tubes that aren't in current production if you want to stay in business. If you can't buy and grade tubes in large quantities, you can't support your product.
 
mep said:
Most companies that design and build tube gear with aspirations of having lots of sales and keeping a stock of tubes for their customers are not going to design with tubes that have been out of production for years and are only available on the secondary markets like FeePay. The 6SN7/6SL7 family of tubes were a very common tube that were used around the world and they are still in production. The simple answer is you shouldn't design a new product to use tubes that aren't in current production if you want to stay in business. If you can't buy and grade tubes in large quantities, you can't support your product.
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Well said. The 6F8G is a very old tube and their numbers are limited.
While I have not heard this tube as a sub in an OPPO, I have heard it in numerous other pieces of equipment all with the same astonishing results.
As with all things audio YMMV.
 
If I could still buy real Mullard EL-34 tubes in quantities and they were tested and matched, I would probably still have my Quicksilver MS-190 with the triode input boards. Mike Sanders designed the MS-190 to run with real Mullard EL-34s as he was running those tubes hard at the maximum plate dissipation rating (25 watts). You are never supposed to design a piece of gear and run the parts at their maximum ratings. It's a recipe for a short life. The real Mullards could take it without breaking a sweat plus they sound great which is why Mike chose them, but modern EL-34s can't take the punishment.

Michael Elliott enlisted Roger Modjeski to design an OTL for Counterpoint called the SA-4. It used the 6LF6 tubes which are out of production and no longer available in quantities to keep these amps running with matched tubes. Owners now pretty much have boat anchors.

The bottom line is that if you are a tube roller and you have a stash of rare tubes and have hit on a great combination for your preamp, amp, phono stage, or DAC, that's great. Just don't wonder why the designer isn't using your magic combination in normal production.
 
jadedavid said:
Well said. The 6F8G is a very old tube and their numbers are limited.
While I have not heard this tube as a sub in an OPPO, I have heard it in numerous other pieces of equipment all with the same astonishing results.
As with all things audio YMMV.
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I know at least one person who preferred the 6F8G with adapter for his Oppo, David Minches
 
mep said:
Maybe you should give it a try Rob.
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Except that neither matched pairs nor adaptors appear to be available from the dealers where I look for tubes, which means dealing with Sleazebay, and I'm not sure how much I want to gamble there.
 
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