Dynaco PAS..Comments please...

[gene_stl]

I find the notion of a "tube DAC" to be an utter non sequitur. All they are is a regular DAC with a tube buffer output stage put there for show.
One of the stupidest audiophile nonsense items.

A dac is powered by densely integrated chips. Even a discrete transistor one would be the size of a washing machine. All a tube output stage does is add unnecessary distortion. Absurd!

 

[raindance]

Tubes can add "reverb" if they're microphonic...

Although technically this is acoustic feedback and not reverb.

Tube buffers have almost no influence on the sound apart from adding undesirable odd harmonic distortion. Any "magic" even harmonic distortion in line stages requires a gain stage and/or an audio transformer. Cathode followers are among the crappiest sounding of all tube circuits and are used in many "tube DAC's".

 

[JeffS7444]

I might argue it's physically impossible for a tube amp not to do that. In fact, if you wanted a certain quantity of information on the output of a tube amp, it would be necessary to reduce the information going in.

But yes, what you're thinking of is impossible. However, consider the little daydream I started with. A tube amp can put the reverb back on the drum skin. A sound that was lost in the recording because they had to pad the kit's mics down so much to deal with the impact of the stick. Rosin on the bow? Can you actually hear that? You can with a tube amp.

Yes, I'm a recovering addict.

Mmm, nice juicy harmonics as illustrated by Pete Millett: If that's what you seek, buy from someone like Millett knows how to properly design a "bad" amp.

 

[raindance]

Pete's projects are well documented and well worth experimenting with. They're not all distortion boxes.

 

[Trif]

There’s much wrong here. First, tubes can’t violate the Second Law. Second, with even inexpensive digital interfaces, you won’t hear the difference between the direct mike feed and the interface output unless you badly misadjust the level. The notion that you’re somehow “losing reverb” or “rosin on the bow” and those can somehow be captured by tube equipment is ludicrous.

Okay, at this point I'm going to apologise. I honestly thought you were older. I've been trying to tease you for your 'the basis of "tube sound" fantasy is the height of foolishness' comment, but you're not getting my references. My bad. I really am sorry.

FWIW, I was talking about recording equipment in the '60s and '70s. Back then, transistors didn't have the headroom to handle the mic's output so we put resistors called "pads" on the mic inputs. By the time the rimshot was brought down enough so the needle wasn't clacking against the stop-pin, the sound of the texture of the drum skin was so low in level it was lost in the noise floor (this is why the first item any engineer added to his rack was a compressor). No, tubes can't "capture" anything, but as @raindance caught on, they can add suitable harmonic and non-harmonic replacements. If you're lucky. Not all tubes are equal. That's where the romance comes in.

Seriously, SIY, I (just) joined this forum because of people like you. You have 6 thousand posts in two years and you're tagged as a technical expert. I'm sure I can learn a lot from you. Maybe you can learn from me. Maybe, once we know each other, we can joke around. I hope so.

 

[SIY]

Okay, at this point I'm going to apologise. I honestly thought you were older. I've been trying to tease you for your 'the basis of "tube sound" fantasy is the height of foolishness' comment, but you're not getting my references. My bad. I really am sorry.

FWIW, I was talking about recording equipment in the '60s and '70s. Back then, transistors didn't have the headroom to handle the mic's output so we put resistors called "pads" on the mic inputs. By the time the rimshot was brought down enough so the needle wasn't clacking against the stop-pin, the sound of the texture of the drum skin was so low in level it was lost in the noise floor (this is why the first item any engineer added to his rack was a compressor). No, tubes can't "capture" anything, but as @raindance caught on, they can add suitable harmonic and non-harmonic replacements. If you're lucky. Not all tubes are equal. That's where the romance comes in.

Seriously, SIY, I (just) joined this forum because of people like you. You have 6 thousand posts in two years and you're tagged as a technical expert. I'm sure I can learn a lot from you. Maybe you can learn from me. Maybe, once we know each other, we can joke around. I hope so.

Trust me, I’m old. Built my first amp in 1966. And have designed and built piles of tube amps and preamps. And refurbished and recorded with 351s. And love humor. So please deal with me on that basis and we’ll get along superbly. Promise!

 

[DonH56]

Yes, tape can bury some details in the noise floor, but once gone it's gone and tubes will not bring it back. What they will do is add some extra noise and low-order distortion to help "fill in the gaps" but they cannot magically restore information that is not there.

And yes, I've designed and owned tube amps/preamps, tube R2R ("open reel") tape decks, done some recording and mastering, etc. But I'm not as old as @SIY.

 

[RoyB]

Thanks for all the great...and helpful....feedback on my question. But I've been admonished a couple of times that I might be on the wrong site....So, is ASR simply a "measurement" site.....and sound quality doesn't matter? This is what seems to be implied. I get it. Measuring stuff can be fun.....but actually listening to a good sound system might be more important? No?

 

[77SunsetStrip]

RoyB, you are in the wrong place for discussing how a good system actually sounds. Measurements tell all is the mantra here. Fact is, measurements and listening are both important. Been at this hobby a loooong time. Only recently ventured into the tube world. Rebuilt/restored a Dynaco ST 70 amp with modern VTA board. No hiss, hum, anything - dead quiet. Compared to my solid state amp, little to no difference in sound. Both sound great.

Don't know about tube pre-amps. Bob Latino is a great source of information. Asked him about pairing the ST 70 with my solid state pre-amp. I would suggest audition time in your system before making a purchase. Bottom line, if you want to try a new or different piece of gear - go for it.

 

[raindance]

Thanks for all the great...and helpful....feedback on my question. But I've been admonished a couple of times that I might be on the wrong site....So, is ASR simply a "measurement" site.....and sound quality doesn't matter? This is what seems to be implied. I get it. Measuring stuff can be fun.....but actually listening to a good sound system might be more important? No?

I think you'll find a balance of folks on here who are OK with gear that adds coloration as well as folks who absolutely must have the very best measuring device, even if said measurements are totally inaudible.

But this is a measurement based forum, and subjective prose is not popular. If you want to make statements about how something sounds, at least do a blind AB test first Discussing how different DACs sound will always be viewed with skepticism as they're pretty much a "solved problem" and you should only hear a difference if the unit you're listening to is very broken. Plus what you hear is just your opinion...

At the end of the day, it's about what makes YOUR ears happy. I'm happy to help you make a sound decision and I'm sure there are others here who would do the same.

 

[RickSanchez]

Thanks for all the great...and helpful....feedback on my question. But I've been admonished a couple of times that I might be on the wrong site....So, is ASR simply a "measurement" site.....and sound quality doesn't matter? This is what seems to be implied. I get it. Measuring stuff can be fun.....but actually listening to a good sound system might be more important? No?

You're fine. As you stated early in this thread:

... but for this system, i want tubes....just because...

You've acknowledged that tubes are your preference -- i.e., you prefer that sound / that look / tinkering with tube equipment / whatever. That's great, we all have our own preferences. (You can imagine what kind of sound I get from my Harman Kardon hk670 + KLH Model 6 speakers ... it's not great and I'm sure it measures terribly vs. modern gear, but I love that system.) Where you could get into some hot water on ASR is if you make claims that tube equipment is more "accurate" or is of "higher quality".

I think some of the push back in this thread is genuinely wanting to help you to not waste money. Going the tube route is fine, but as SIY mentioned earlier: going down that path with decent + reliable tube gear may cause a lot of heartache if you're trying to stay under $1,000.

 

[RoyB]

Thanks all... appreciated

 

[DonH56]

There are always subjectivists saying "sound does not matter to objectivists" and of course that is silly. It matters a great deal and we all listen to our equipment quite carefully at times. But we are much more interested than "pure" subjectivists in the why? behind differences in sound and measurements can tell us that. And also help point out when there are no differences, or that the differences are in our heads (bias). Because perceptual bias is so very strong it is easy to fool yourself (myself) with listening tests, especially unstructured tests with essentially no controls such as level matching and blind or double-blind experiments to remove aural and visual bias.

Measurements and controlled listening have disproved many audiophile myths, and verified the truth in others.

There is a tendency to elevate measurements beyond audibility, e.g. choosing a component solely based upon 120 dB SINAD over another with "only" 110 dB. There are many other factors that matter -- and we can measure them.

On the flip side, not all subjectivists completely eschew measurements and specifications, taking at least some into account (power output is a typical example). But changing cables with essentially identical specs to change the sound, or adding distortion to the original source to "improve" it, run contrary to the goal of building audibly and measurably transparent gear. Listening tests can provide a wealth of information about what is audible, but most of the time the tests are uncontrolled and any real differences masked by the lack of critical listening test methodology and general desire to prove an audible difference that may or may not be there.

Years ago, measurements and specifications were commonly used to evaluate gear in addition to listening tests, and engineers who understood the circuits that created the gear revered. Now, perhaps in part due to things like TAS and the whole "subjective listening is all that matters" approach, measurements and engineers are reviled, marketing runs wild claims with no technical support, and objectivists and subjectivists have been pushed to extremes instead of taking a moderate middle ground.

Such is life...

 

[RoyB]

Great piece right there......Back in the 80s, I owned a HiFi store on the East Side of Providence RI. Large number of colleges with accomplished "acoustic" musicians. Woodwinds, strings, brass, etc......They would come into the store with various music. Some on reel to reel with single mic recording a a small assembly or a quartet.....We sold all the better brands.....NAD, Dahlquest, KEF, B&O, SAE, Yamaha, Tandberg, Nakamichi, etc.....It always amazed me how many of them bought B&O loudspeakers with NAD electronics and if they had more $$ they would choose Dahlquest.....When the "Knowing" staff could show "on test equipment" that other products measured better.......I'm totally convinced that it had to do with "phase irregularities" that other speakers and electronics didn't bother with......Those were fun times!

 

[JeffS7444]

Thanks for all the great...and helpful....feedback on my question. But I've been admonished a couple of times that I might be on the wrong site....So, is ASR simply a "measurement" site.....and sound quality doesn't matter? This is what seems to be implied. I get it. Measuring stuff can be fun.....but actually listening to a good sound system might be more important? No?

You want science to confirm what you already "know", but this isn't how scientific inquiry works! In this instance, you've already decided that tubes are the answer, and aren't allowing for the possibility that it ain't necessarily so.

 

[MakeMineVinyl]

Pity the Want Ad wasn't still around. I'd suggest trying to find a pair of Mark IIIs and loading them with JJ KT66s.

The MKIII uses KT88s or 6550s. The older MKII used EL34s and I assume KT66s. But yes, I get your overall point.

 

[Jim Matthews]

...if they had more $$ they would choose Dahlquest.....When the "Knowing" staff could show "on test equipment" that other products measured better.......I'm totally convinced that it had to do with "phase irregularities" that other speakers and electronics didn't bother with......Those were fun times!

The midbass driver in the DQ10 was mounted in an open baffle.

Listening for the timbre of you chosen instrument would play to the strengths of a wideband driver as in the DQ10.

Back when I could hear frequencies that high, I found them strident.

It was a clever, handmade solution to the problems posed by playback in real rooms with less capable amplification than we have today.

 

[DVDdoug]

The thing about tube amplifiers is that if they have a particular "tube sound" it will sound different from any other amp so you have to listen before you choose any particular amp.

And if they have a particular kind of distortion the sound will likely change when the tube ages or when you replace a tube. But, that's not always the case and you can design a tube amp that's immune to normal variations.

Guitar amplifiers are designed to alter the sound, especially when over-driven, so guitar players usually have their favorite amp and most guitar players seem to prefer tubes.


...Speaking of Dynaco, I had a ST-120 but it died at least 3 times and when Dynaco went out of business I re-built the output stages with "modules" and I made a small change to the power supply. It's been working for a few decades now! Currently, I'm using it to drive a pair of subwoofers. (A little underpowered for a subwoofer amp by todays standards but it's plenty for my living room.)

...One time, maybe the 1st time the ST-120 died I killed it by building an RF oscillator when I was trying to build a preamp.

 

[ChrisWoo]

sth like that, unless you find version with remote slightly more expensive (lite audio LS9) but not sure if still available...

I know this thread is quite old now but I thought I should mention my experience with the Lite Audio LS9 (Jadis 200 clone). I bought one about 4 years ago (£560 delivered from China to UK). The sound quality is brilliant. I took the lid off and the build quality is excellent. Top brand capacitors, etc. I would not swap it for a "real" Jadis for the following reasons:
- It has a remote, which is essential for me. The Jadis doesn't.
- It uses 12AT7's not 12AX7's. I don't need the extra gain from the X's and I like tube-rolling. NOS AT's are much cheaper than the AX's. I am using NOS long plate Ei's from Yugoslavia. I also tried NOS Mullards, but the Ei's were more to my taste.
- It's more compact. The Jadis is an ugly great thing that would not meet my wife's approval!

Not all Chinese clones are bad.

 

[RoyB]

I'm the OP....Figured since this older thread came back up, I would let you all know what preamp I decided on......Schiit Freya......So far it is a wonderful preamp.....No complaints whatsoever......Also just picked up a pair of KEF LS50 Meta.....So along with the VTA ST120 tube amplifier.....The listening is fine over here!