Tube Rolling for Moscode 401HR

zybar · « **on:** 19 Nov 2006, 08:05 pm »

Quote from: 95bcwh on 19 Nov 2006, 07:45 pm

Tvad4, why all of the sudden you have so many tubes for sale??? Can you recommend another tube for me, something that's even "warmer" than the Mullard... thanks.

Which Mullard tubes are you using Barry?

Can you describe in more detail what you mean by warmer?

George

95bcwh · « **Reply #1 on:** 19 Nov 2006, 08:29 pm »

Mullard 12AU7, NOS, made in Blackburn UK, back in 1960.

What I have in mind when I says "warmer" is more high-frequency roll-off and also more mid-range.

How's your experiment with CCa and Amperex?

Quote from: zybar on 19 Nov 2006, 08:05 pm

Quote from: 95bcwh on 19 Nov 2006, 07:45 pm
Tvad4, why all of the sudden you have so many tubes for sale??? Can you recommend another tube for me, something that's even "warmer" than the Mullard... thanks.

Which Mullard tubes are you using Barry?

Can you describe in more detail what you mean by warmer?

George

tvad4 · « **Reply #2 on:** 19 Nov 2006, 08:37 pm »

Quote from: 95bcwh on 19 Nov 2006, 08:29 pm

Mullard 12AU7, NOS, made in Blackburn UK, back in 1960.

What I have in mind when I says "warmer" is more high-frequency roll-off and also more mid-range.

How's your experiment with CCa and Amperex?

Quote from: zybar on 19 Nov 2006, 08:05 pm
Quote from: 95bcwh on 19 Nov 2006, 07:45 pm
Tvad4, why all of the sudden you have so many tubes for sale??? Can you recommend another tube for me, something that's even "warmer" than the Mullard... thanks.

Which Mullard tubes are you using Barry?

Can you describe in more detail what you mean by warmer?

George

You could try Tungsram 12AU7, RCA 5814A or Brimar 12AU7. The Brimar are the most rolled off and "midrangy" tubes I've heard in my system.

zybar · « **Reply #3 on:** 19 Nov 2006, 09:26 pm »

I second trying the RCA 5814A triple mica tubes.

I have a pair in house and will let you know how they sound.

George

JoshK · « **Reply #4 on:** 19 Nov 2006, 10:33 pm »

George, do you have a pair of 6H30pi's to try? I got a lot of 10 of the 6H30pi-DR's coming. I could loan you a pair to try. I also have a ton of the 6N6P (similar to 6H30, 5687, 7044, et al but I believe the pinout is the same as the 6H30/6DJ8, but I'd need to check that). 6N6P is suppose to be a touch creamier than the 6H30. I also have a ton of the 6N1P which is the russian version of the 6DJ8, but requires a bit more heater current.

95bcwh · « **Reply #5 on:** 19 Nov 2006, 11:23 pm »

are you putting these up for sale? aa

Quote from: JoshK on 19 Nov 2006, 10:33 pm

George, do you have a pair of 6H30pi's to try? I got a lot of 10 of the 6H30pi-DR's coming. I could loan you a pair to try. I also have a ton of the 6N6P (similar to 6H30, 5687, 7044, et al but I believe the pinout is the same as the 6H30/6DJ8, but I'd need to check that). 6N6P is suppose to be a touch creamier than the 6H30. I also have a ton of the 6N1P which is the russian version of the 6DJ8, but requires a bit more heater current.

tvad4 · « **Reply #6 on:** 19 Nov 2006, 11:33 pm »

Quote from: 95bcwh on 19 Nov 2006, 11:26 pm

I found this on Audiogon, for only $15..too cheap to be true..am I looking at the right RCA?
5814A 12AU7 RCA 1 $15 SU - 3 MICA BLACK PLATE

See this link for the full ad:
http://cls.audiogon.com/cgi-bin/cls.pl?accstube&1167764702

thanks!

Those don't look like the RCA 5814A I have (which are actually labeled JRC 5814A). Mine were purchased from Andy at Vintage Tube Service and cost just over $100/pair.

95bcwh · « **Reply #7 on:** 19 Nov 2006, 11:38 pm »

Thanks Tvad4, what about this Brimar:
http://cgi.ebay.com/BRIMAR-12AU7-13D5-TUBE-AMPLIFIER-PREAMP-VERY-RARE-L-K_W0QQitemZ180046522698QQihZ008QQcategoryZ50598QQssPageNameZWDVWQQrdZ1QQcmdZViewItem#ebayphotohosting

tvad4 · « **Reply #8 on:** 19 Nov 2006, 11:46 pm »

Those are the correct Brimar tubes Barry, yes.

JoshK · « **Reply #9 on:** 19 Nov 2006, 11:48 pm »

Quote from: 95bcwh on 19 Nov 2006, 11:23 pm

are you putting these up for sale? aa

Quote from: JoshK on 19 Nov 2006, 10:33 pm
George, do you have a pair of 6H30pi's to try? I got a lot of 10 of the 6H30pi-DR's coming. I could loan you a pair to try. I also have a ton of the 6N6P (similar to 6H30, 5687, 7044, et al but I believe the pinout is the same as the 6H30/6DJ8, but I'd need to check that). 6N6P is suppose to be a touch creamier than the 6H30. I also have a ton of the 6N1P which is the russian version of the 6DJ8, but requires a bit more heater current.

No, I was just going to loan him a pair to try.

zybar · « **Reply #10 on:** 20 Nov 2006, 12:24 am »

Quote from: JoshK on 19 Nov 2006, 10:33 pm

George, do you have a pair of 6H30pi's to try? I got a lot of 10 of the 6H30pi-DR's coming. I could loan you a pair to try. I also have a ton of the 6N6P (similar to 6H30, 5687, 7044, et al but I believe the pinout is the same as the 6H30/6DJ8, but I'd need to check that). 6N6P is suppose to be a touch creamier than the 6H30. I also have a ton of the 6N1P which is the russian version of the 6DJ8, but requires a bit more heater current.

Josh,

The stock tubes are Sovtek 6H30Pi's. I have found that the following tubes in the same location sound better:

Mullard 6922
Mullard Blackburn 12AU7
Siemens CCa Gray Plate
Amperex Holland Pinched Waist

All of the above are expensive to extremely expensive and most would expect them to be significantly better than the stock Sovtek tubes.

Which 6H30Pi's do you have?

I will have to ask George Kaye about the 6N6P and 6N1P tubes as they aren't listed on the amp.

George

zybar · « **Reply #11 on:** 20 Nov 2006, 12:36 am »

Some comments on some of the tubes I have been trying (in the outer positions only):

Amperex Holland Pinched Waist compared to Mullard 6922

The top end is so alive and detailed (hopefully not too much over a long listening session) and the bottom is very impactful and solid. I am also hearing little cues and details very easily.

The music seems like it is taken apart and put back together in such a way that I can hear everything individually and together at the same time.

The only "negatives" are that it doesn't have the bloom, warmth, and air that the Mullard Blackburn 12AU7's had or as wide a soundstage.

Mullard Blackburn 1960's 12AU7 compared to stock Sovtek 6H30pi's

top end is more extended and airy
overall presentation is more holographic
guitars and voices have more presence and body
a little deeper soundstage
initial attack is better defined and has less glare

Mullard 6922 compared to the Mullard Blackburn

Deeper, tighter bass
More drive and authority
Soundstage is deeper and larger
Less holographic and airy sounding

Out of the above batch, I prefer the Amperex Holland Pinched Waist.

Stay tuned for comments on the CCa Gray Plates against the Amperex Holland Pinched Waist.

George

JoshK · « **Reply #12 on:** 20 Nov 2006, 01:26 am »

Sovtek 6H30Pi's are new production, said to be just ok. The old stock 6H30PI-DR's (ones used in BAT) are said to be better, which is what I have. How much better? No clue. My 6N6Ps are old stock too.

TheChairGuy · « **Reply #13 on:** 20 Nov 2006, 03:33 am »

George,

The Moscode has pretty tightly regulated power supplies....so you should be able to use (generally, cheap) 6n1p's in it. Even cryo'ed/NOS they are cheap - like $30.00 a matched pair. Mr. Kaye should of course know better than little uninformed I

My Dynaco PAS-4 pre-amp came with 6922's...I tried some recommended Russian Rocket 6H23's, some/various NOS 6922's (the best to me were the pretty cheap Sylvania's I bought...circa 1955 or so), 6dj8 (everyone of these sounded wrong to me) before I found the 6n1p's.

I bought standard cheap Svetlana's for something like $12.99 a pair and was hooked....these were the absolute best above all others tried (and the cheapest). So I bought apair of NOS/Cryo'ed by Tubeman in FL (Kenneth Chaite) and it's been no looking back since. They just outclassed the others in near every dimension that mattered to me.

Every application is surely different, as are all of our subjective impressions, buth the cheapest tubes were the best for me. And, they were the 6n1p's (whether cryo'ed NOS or right off the shelf/matched).

Hope they will work in the Moscode...they are worth trying for the money, for sure.

JoshK · « **Reply #14 on:** 20 Nov 2006, 03:47 am »

I've heard from a few places that all the 6N1P despite their marking were made at the Svetlana factory. I have seen some reports from people who love them and a couple who don't. I think it may be circuit dependent but my theory is that it is based on the heater supply.

You can starve a tube for voltage (a bit) but you shouldn't starve them for current. Since they require more current than their 6922 counterpart, my theory is that some components don't have enough current in their heater supply to do them justice and that is why some do not like them. It is just a theory.

I was recently reading a long thread on diya about doing constant current versus constant voltage in the heaters and there wasn't any hard fast conclusions (as if there ever is) but it seemed that there was more empirical evidence for constant current, especially with DHT (6n1p is not).

I am not sure this post helped anyone....

except that maybe you should try them for yourself and they may work for you. They are dirt cheap. I paid ~$5/ea in lots of 8 off ebay (direct from Russia).

lonewolfny42 · « **Reply #15 on:** 20 Nov 2006, 03:53 am »

Found this.......helpful, I don't know....

JoshK · « **Reply #16 on:** 20 Nov 2006, 04:01 am »

That is a good reference for the 6n1p. It more or less says, that yes, they are a bit different tube (like 5687 vs 7044) and have a bit of variance in their parameters which makes the 6n1p less suitable for lower B+ voltage (HT = high tension = B+). So, for instance, the Lite DAC60 uses a 90V B+ which would not be good for the 6n1p.

TheChairGuy · « **Reply #17 on:** 20 Nov 2006, 03:45 pm »

Darn good reference, WolfyChris

I even understood some of it

The plate voltages being higher at 250v might be the reason why they also tend to run hotter than the other tubes I've tried. But as they are small signal/input tubes, it's not the inferno that hotter running/larger output tubes can be. You never stack anything on tube amps (or, generally, tube preamps) anyhow, so I don't see how it'll matter for longevity purposes.

I was told if you have regulated/buffered power supplies to each tube and that spot designates a 6922/6dj8 variant, you can use a 6n1p in it's place. Best to check with maker first, however, before going down that road. I know that Audible Illusions 3a owners cannot use the 6n1p, for instance.

I bought my first matched pair (new non-labelled, non-cryo'ed) from Triode Electronics:http://store.triodestore.com/6nrusmatpair.html

95bcwh · « **Reply #18 on:** 10 Dec 2006, 12:15 am »

I need to re-surrect this thread.

My current tubes combo in Moscode is Mullard 12AU7 1960s NOS (Blackburn) as the outside pair, and the stock 6CG7 as the inside pair.

I just received a pair of Brimar 13D5 (12AU7). I took out the Mullard and roll in the Brimar. I was surprised just how similar the sound between the Brimar and the Mullard, I could hardly tell them apart.

Next I tried taking out the 6CG7 and roll in the Mullard as the inner pair, strange thing happen, I hear noise (zzhhzzhhhzzzhh)!! I then take out both the Mullard and the Brimar, switch their location so now Brimar is inside and Mullard is outside, still I hear the same noise.

So now, I leave the Mullard as the outer pair, took out the Brimar and re-insert the 6CG7, the noise is gone!

. I then swap out the Brimar with the Mullard, I heard no noise again!

So, my qeustion is, is there something wrong with using 2 pairs of 12AU7 in Moscode?

Thanks
barry

tvad4 · « **Reply #19 on:** 10 Dec 2006, 12:20 am »

Patient: "Doctor, it hurts when I do this."

Doctor: "Don't do that."