Rectifier tube for Dynaco ST-70

[kjohnsonhp]

I need to replace my Ruby 5AR4C rectifier tube. Would a more expensive tube sound any better? Should I consider replacing the tube with a pair of diodes?

I'll read the ST-70 mod papers tonight.

Another question: do you ground the TT by screwing a sheet metal screw into the PAS3 chasis?

Point out any pre-amps you see for sale...I don't think the PAS3 is the answer but it allowed me to play my old (mint) Ted Nugent "Cat Scratch Fever" lp last night. I noticed a lot of the pres don't have phono and the phono stages are nother $500-$600 (ie Wright Sound).

I think my biggest concern with CDs on my Cornwalls is many of my rock cds have a strong cymbal beat that is just too dominant. Recordings without this sound much better. On the cymbals the tweeters seem to jump out from the rest of the sound. Using the ST-70 connected to the Outlaw is a notable improvement but some recordings just seem to be mixed with loud cymbals. For these I can't turn it up too much beyond 80db.

I've noticed Klipsch seem louder at the same volume than more laid back speakers like the Onix Rockets.

Putting the Corns in the corns produces some pounding bass and I've always enjoyed my imaging...I was listening to all 2-channel tubes wonder if my center channel and subwoofer were on...

[NOSValves]

Well I'm going to get some heat on this one but here goes !!

I have been running a Sovtek $12 5AR4 bought from good old Ned at triode on my ST-70 with 500UF in the B+ and 100 UF of that on the first section and the Sovtek is taking it like a dream for the last 3 months or so. I also think the sonic benefits of a mullard are hogwash. The rectifier does a specific function turns AC into DC with the proper amount of filtering there can be no sonic signature left the only way a recitfier could adverely effect the sound is by providing more AC ripple in the DC conversion than a NOS 5AR4 if after its filtered the DC is clean that is all that matters if the circuit is lacking filtering then a Sovtek may effect the sound maybe. Buy a Sovtek and forget it. If there is a sonic difference it will be small at best.

I would stay away from diodes that could really have a effect on the sound and tube life.

I Have a EICO HF-85 that I would sell you for $375 its completely head to toe rebuilt great sounding preamp and in great cosmetic shape. For $900 complete Amp and Preamp I'll throw in my ST-70 to boot and I can finally buy my dream Mark III's .

Craig

[kjohnsonhp]

Craig,

Thanks! No mullards, no diodes. I'll plug a new 5AR4.

I'm thinking about your offer. My perception of the EICO is similar to my PAS3 unless you've modernized the topology, tone controls, etc.

I'm also wondering if I should bite the bullet and get something like the Wright Sound WPL20 Phono/Line Preamplifier (see the one on audiogon) and then later keep looking for a pair of Mono8's.

I just don't haven't heard this stuff.

I'm reducing the toeing tonight and I've got the ST-70 connected to the Outlaw again...I couldn't handle the Outlaw alone.

[kjohnsonhp]

Any opinions on toeing Cornwalls?

It seem that less toeing helps reduce the dominance of the tweeter--less bright. Aiming the tweeters right at the listener seems to be too much tweeter and perhaps more R/L/C (not as good of imaging)

Placing the Cornwalls tight across the corners--as if they were KHorns seems to work, too. If the tweeter was a laser beam the intersection of the two beams would be in front of the listener and not at the listener.

Close to walls helps build a driving bass.

Pulled out 3'-4' from each wall and aimed at the listener seems too bright.

I guess across Corners or along Walls...hmmmm

I'll keept experimenting but I've found some spots where the imaging is fantastic...disconnected with the speakers.

The tweeters for some of my rock recordings are just too dominant with cymbols (placement has helped a lot). At times I want to put a sock over the tweeter.

[jazman]

KJ,

I totally disagree with Craig on the issue that a Mullard 5AR4 is no diferent that a Sovtek. There is quite a difference in the sound that results using a Mullard instead of a Sovtek. Craig tends to discredit anything that involves a cost greater than he's willing to pay. And Craig, I don't want to hear the audiophile crapola argument either. KJ, take the time to find a decent Mullard, even a used one that tests good will sound better than the Sovtek. And yes Craig, I have several different 5AR4's and GZ34's, so I do have some experience listening to them. If you want specifics KJ, send me an email.

Klipsch out.

[NOSValves]

Jazman,

I could care less what you want to hear !! The fact that a Sovtek cost more than a Mullard has nothing do to with my conclusion. I happen to have at least 6 Mullards sitting here now so why would cost be a issue. If I tend to base my decisions on cost then why is it I just spend a small fortune buying Auricaps and became a OEM for them if your opinion was true I would of just bought Xicon 25 cent caps and said they were the best thing since sliced bread ! My conclusions are drawn by actual testing of current Sovtek 5AR4's !! When is the last time you heard a brand new Sovtek made today and how many have you heard ?? You are such a AUDIOPHILE. I bet a 5AR4 does make a large difference in a weak set of Moondogs they need all the help they can get !!

Craig

[NOSValves]

KJ,

The HF-85 is nothing like the Pas 3 in any way shape or form completely different circuits that happen to both use 12AX7's and 6X4 rectifier. The HF-85 would wipe the floor with the Pas 3 without breaking a sweat in sound quality. I think you would be shocked at the difference.

But I tell you the Wright WPL20 Phono/Line Preamplifier looks awesome and if you can afford it. I would think its the better investment here ! It looks great and if I'm looking at the same one up for auction it looks to be a great deal with everything included.

Craig

[kjohnsonhp]

Thanks Craig!

I'm flying blind (or more appropriately "deaf") on the delta between these tube products. The only data I have is what I've read which is primarily on this forum. It seems the PAS3 is bottom rung so I'm not surprised by your comments on the EICO. I did a search on the forum and found only one review of the EICO pre. There have been several good comments on the Wright in that price range....another price league compared to the EICO...I guess I just don't know what my Cornwalls could sound like with either.

The Wright gear on audiogon seems attractive...and a good value retention. I'm just not sure how much I should plan to allocate...thinking on that.

Scott 299 -- $500

EICO/ST-70 -- $900

Wright pre & mono8's -- >$2k

MMF 5 or MMF 7 or ?

[jazman]

Craig,

You are so full of crap! I could care less about you dealing Auricaps. Your statements about being cheap are on record in this very forum. I did not make that up. I won't dignify your idiotic statement about Moondogs with a rebuttal. It's your standard, expected, lack of class to knock what you don't know about. All of a sudden you're "Mr. Tube amp Expert".

What's the difference between a Sovtek made today as opposed to one made 2 years ago, 5 years ago, 10 years ago? Please explain? Please explain exactly what period of time you're talking about? Lastly, are you stating that there's no difference in the sound of a Mullard GZ34 and a Sovtek 5AR4? Yes I've heard Sovteks, not long after purchasing my Moondogs and I ditched them right away. Let's cut through the crapola and get down to discussing the issue. Can you manage that? Maybe everything sounds the same at 110db levels, so please educate this ignorant AUDIOPHILE,....... IF YOU CAN?

Klipsch out.

[NOSValves]

Jazman,

What production processes do not improve thru the years ?? You making a royal a$$ of yourself once again !! It is pretty well known fact that the tubes coming from Euro these days have improved by a large margin. The failure rate alone not that many years ago was very large on Sovtek 5AR4 not any more these companies are all fairly new ! Wake up and quit being so closed minded.

I can tell you one thing in the last year I have forgot more than you WILL EVER KNOW about tube amps and Tubes !! How many amps have you rebuilt lately or redesigned if ever Huh ??

My remark about moondogs is a serious statement ! Said in a snappy way because your being such a A$$ again. They are weak 3 watt amps and probably are more influenced by slight changes in tubes !! Oh and I have heard Moondogs now and I was not at all impressed.

Craig

[NOSValves]

KJ,

Where you want to go with this hobby is entirely something you will have to decide. I personally like the vintage stuff. But some of this new stuff is really cool but has the price tag to go with the cool. I seriously don't think the sound quality can match dollar for dollar value with the vintage. But its a descision you will have to make !

Craig

[jazman]

NOS,

You still did not answer the questions I posed. You are the one making as *** out of yourself. YOU made a declaration that there is really no difference between a Mullard and a Sovtek rectifier soniclly and can't back it up. BTW, you still did not say what years of production you were speaking of. Maybe you haven't spent enough time with an amp that can allow you to hear the difference. It's not a matter of being close minded, but simply being open eared.

Your sour grapes drivel is really quite pathetic, AND I don't need your validation of Moondogs to know a first class amp when I hear one. I suggest you go pick on someone who's mind is as small as yours, since you seem neither prepared, nor capable, of discussing the merits of the issue at hand.

Klipsch out.

[Marvel]

I'll go ahead and check in on this one. The specific design of the power supply circuit can certainly change the sonics (hi falutin' term) of a tube amp. Probably more so on a lower powered amp, as all parts are more critical (not that they aren't critical on a higher powered amp). That being said, the Sovtek may sound no worse in an ST70 than a Mullard. For $12 you can afford to try the Sovtek. Borrow a Mullard and compare.

Marvel

[NOSValves]

Marvel,

good info !! Right on the money

Jazman,

Your not worth any further response ! I have no reason to prove anything to you.

Craig

[kjohnsonhp]

Here's a technical person's perspective but not an audiophile perespective...this also isn't an opinion based on listening experience. It's just fuel to the debate.

Thanks for the two opinions. I'll have to listen to the two and see if I have a preference.

If we were to reset the bias according to

the specification of each tube, I doubt that there would be any difference

"tonally", the only change in signal characteristic would be a change in the

output power of the tubes based on the emmissions of the retifier. The

higher the emissions of the rectifier, the more efficient the tube, hense

the higher the B+ ; leading to higher plate voltage on the 4 output tubes.

Pushing the plate voltage higher will move the operation of the tube further

along the characteristic curve, but shouldn't affect the sound

quality directly. If a mullard and sovtek are operating at the same

efficiency and voltage output level, the tonal characteristics should be the

same.

[NOSValves]

KJ,

If a mullard and sovtek are operating at the same

efficiency and voltage output level, the tonal characteristics should be the

same.

They operate Identical to one another in Voltage output level and efficeincy.

The Sovtek got a bad rep years ago when failure rates were high and some people formed a opinion that they will not allow current tubes produced to over come. Triode at one time was hot testing all Sovtek's before reselling to save the failure rate costs this is no longer required the factory refined there quality control as they matured. JJ Telsa is now making a 5AR4 also but I have not tried one yet.

Craig

[sunnysal]

I tried swapping loaned mullards 5AR4s for my new sovteks in my Mk IVs and could not say that I detected a consistant difference in sound. However many, many people I respect say that in their setups they can hear differences when swapping rectifiers. I suspect that in a lower powered, more revealing amp, or different circuit topologies, or with different complementary components someone might be able to hear the differences. I know that jeff lessard says that different rectifiers make noticably audible differences in his 2A3 and 300b amps. though he challks it up to operating points mostly, running the triode tubes "hot" or "cold". As always, I recommend auditioning the two tubes, most audiophile hobbiests are more than willing to loan tubes for testing, especially if you invite them over for drinks and some listening. I will have the chance to swap various 5U4g, 5U4gb, 5AR4 and 5R4 rectifiers in my new 2A3 PP amp and will report back my impressions. regards, tony

[jazman]

Marvel, Tony,

Thank you. You both have pointed to simple information I was attempting to convey before Craig entered into his name calling and attempts to degrade equipment he knows little to nothing about. I was merely attempting to clear up that there is a difference, and it would be up to KJ to explore whether the difference was evident with his hardware, and worth the expense to him.

And just for the record Craig, I'm more than certain that I have actualy "listened" to more different tube amps than you've ever seen on your workbench. You should stop pretending you're such an expert, when in reality do very little other than "swap and solder" parts. You remind me more of a tire changer claiming to have the knowledge of the engineers who designed the tire. You make grand attempts to be such a large fish in the little pond of this forum. I actually correspond with individuals who do design circuits, build amps, preamps, phono preamps, and other audio equipment who don't display your pompous attitude. You're no circuit designer of anything! You really should give it a rest and stop popping off.

If you wish to attempt to wage a continuing war of words with me, have at it by merely sending me an email and I will happily oblidge, but be forewarned that you are overmatched. Know your limitations!

Klipsch out.

[LonestarBlues]

I like and respect both NOS Valves

and Jazzman. I will probably get flak for this, but here goes. Both of you need to lighten up, grow thicker skin and quit with the insults. Just agree to disagree. Life is too short for such trivial

b.s. I am pretty much just a lurker and not a prolific poster. But I have seen the verbal warfare

between other forum members in the past. And I can remember Kelly leaving several times because of disagreements that escalated and got out of hand. It would be nice if old MobileHomeless would return. I did not always agree with him, but Kelly was both knowledgeable and entertaining

with his prolific writing style & humor. I would welcome Kelly's return. I am still too much of a tube novice to know if there are sonic differences in rectfier tubes. I have never rolled tubes in the Moondogs. I need to buy a spare backup set of tubes for my Moondogs. I have Sovtek 2A3, Brimar 6SN7 & Mullard GZ-37 rectifier. The only tube rolling I have done is in my Welborne Labs Revellie preamp-I have 3 sets of 6SN7 pairs-JAN Philips WGTA, Slyvania chrome domes & RCA Redbase 5692. Currently running the RCA tubes in the Revellie. I plan on trying out a Sovtek 5AR4 & or JJTesla 5AR4 & NOS 5AR4 sometime in the future. Also going

to try Electro Harmonix 6SN7 & some other NOS 6SN7 tubes & a pair

of NOS 2A3 tubes. I just don't want to spend an arm & a leg on NOS tubes. I am still reading and researching about the sonic qualities of different brands of NOS tubes. I always liked the Saturday Night Live skit with

the line Simmer down now. Maybe that humorous line is apropos to this disagreement.

Regards, Mike

[NOSValves]

Jazman,

When will you ever get the point that your opinions matter more to yourself then anyone else ? The fact of the matter is we were discussing rectifier tubes use in amps that we both own here. I have tested what the differences are and its nothing. You pipe in saying there is a large difference and with your amps there may very well be. What is good for one circuit is not always good for another. The rectifier brand really won't have a large contributing factor in most amps. I never questioned that the Moondogs would benefit and I know exactly why do you ?

The fact of the matter is you were relating advise to KJ that is derived from a completely different set of circumstances and it was wrong. But rather then admit that you would like to tell the world your verbal skill are so high I should run off with my tale between my legs. Trust me dude I'm not the least bit scared !

This entire little spat could of been avoided if you would of just politely said you think they do make a difference. But nope you had to name me and then explain how I arrive at my conclusions. You have absolutely no right explaining my decision process !! You do not know me at all !! What a arrogant a$$

Later