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  »  New  DHT driver & input..  Effects of radiation...  Melquiades Amplifier  Forum     25  165381  02-01-2007
  »  New  The one-stage Melquiades...  Tubes vs. Speakers vs. FR...  Melquiades Amplifier  Forum     73  458703  04-21-2007
  »  New  The single-stage Milq and power Supplies...  Just the tank...  Melquiades Amplifier  Forum     10  63869  05-03-2007
  »  New  The 6E5P tube data...  Bartola Valves: 6e5p beam tetrode SPICE model...  Melquiades Amplifier  Forum     44  322445  07-23-2007
  »  New  6 Channel Version of Super Melquiades..  The first Milq screw up....  Melquiades Amplifier  Forum     131  869131  08-08-2007
  »  New  My (Amplification + Acoustic System): what is next?..  Macondo and Melquiades in the NEW room....  Audio Discussions  Forum     41  203854  01-10-2008
  »  New  Incorporating active crossovers into DSET..  Thanks...  Melquiades Amplifier  Forum     2  29986  07-22-2008
  »  New  About the life-expectancy of the new production tubes...  Stressing the damn contemporary tubes....  Audio Discussions  Forum     9  62811  12-29-2008
  »  New  Small SET’s bass, besides everything- is it about power..  Importance of OPT and type of tube for SET amp bass per...  Audio Discussions  Forum     4  61380  01-12-2009
  »  New  Macondo: new horizons. A few thoughts in context Zander..  What does make a playback to stop?...  Playback Listening  Forum     9  48463  02-02-2009
  »  New  The period DHT tubes and Swastika..  Maybe there is another solution...  Melquiades Amplifier  Forum     1  17843  04-30-2009
  »  New  Some thoughts about Milq’s MF filter..  High-Pass RL Filter calculator....  Melquiades Amplifier  Forum     2  22213  05-02-2009
  »  New  The DHOFT topology? Do not try it home...  A medley of slow-cooked triodes....  Melquiades Amplifier  Forum     3  31128  05-04-2009
  »  New  Why the tubes shall be the same?..  Not optional anymore?...  Melquiades Amplifier  Forum     7  39382  05-11-2009
  »  New  Valve Technology Timeline..  A good video about tubes making....  Audio Discussions  Forum     5  73165  06-18-2006
  »  New  The DSET perspective examines the Herb Reichert article..  Are you still in Reutlingen, Germany?...  Melquiades Amplifier  Forum     5  67322  07-01-2009
  »  New  About the Critical Audio Tune ™..  “Critical Audio Tune” bay-leave in the soup......  Playback Listening  Forum     5  33382  08-29-2009
  »  New  A full-range quality-triode? Does Size mater?..  A full-range quality-triode? Does Size mater?...  Melquiades Amplifier  Forum     0  10984  12-02-2009
  »  New  About Stupid Dynamic..  Misplaced dynamics....  Playback Listening  Forum     1  13094  08-21-2011
12-03-2008 Post does not mapped to Knowledge Tree
mumford
Posts 10
Joined on 06-10-2008

Post #: 61
Post ID: 9070
Reply to: 9069
John Broskie's Partial feedback amplifier
fiogf49gjkf0d
You can eliminate the driver stage and drive a DHT in just one stage, because your source or preamp is sand based and has plenty of current drive.

Page 10 of the PDf showed an example of driving a 300B DHT to full output with just +/- 4ma.


http://www.tubecad.com/march2001/2001_03.pdf


12-04-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 62
Post ID: 9071
Reply to: 9067
Randomness vs. freedom and the Homework # 4334
fiogf49gjkf0d

 Paul S wrote:
This may also be a factor in the "randomness" capability, which is really only freedom of movement, and not "randomness", per se.

OK, is it “randomness” of “freedom of movement”, the question is not about juts semantics. Since Paul said I have been thinking about is and I have to admit those thought fascinate me. The “randomness” would imply the will of amplifier vs. “freedom of movement” would imply the transparency of amplifier to external source of pace randomness. It is very much not the same.

I feel Pail was wrong and I still would insist that it is not “freedom of movement” but randomness. I never experience in live music neither “freedom of movement” nor randomness, the pace of live music whatever it is and there is not reference in my mind to some kind of pace-setting framework. What I question a pace of live event I equation it in context of musical idea and the “program” of the piece. What I question a pace of reproduced muss invent then in addition to original performing pace I recognize the pace aberrations of playback. If so, and if we take the pace aberrations out of repentances of attention then we can see that the timing aberrations are not connected to the timing of original events and can’t be called “freedom of movement”. The “freedom of movement” implies high amplitude of obedience of aberrations to the original pace but the original pace doe not exist.

So, what we have here is not “freedom of movement” but rather a randomness of amplifier’s timing self-control. I think that this randomness comes with randominisation of error. It like when we have frequency-centric noise injected into sound then we recognize it as “harmonic problem” but if we have more or less white noise then we do not feel that the noise interact with sound. A good example is a LP record noise. It is random my nature then we play record and have no problem. However, if the record has scratch on one side and each turn of the record we have a click that come at the same “pace” then it annoys us tremendously…. Now pretend that an amplifier somehow might take this non-unsystematic click from this scratch and spread it appearance at random moments. Then we will me bother but the click much less as then the click will be not interacting with the pace of the plays musical material.

 Romy the Cat wrote:
OK, here is an easy homework: how to randomize elections flow but do not create microscopic? The answer is actually contains in the question. The answer is one of the solutions that my first thing that I will be trying sometimes.

Now, in context of what I expressed in the first part of the post I am planning tonight to make some actual experiments with my single stags IDHT driver, trying to “randomized” the electrons flow, it is not truly randominisation but insertion of something soft of geometrical  errors. If it works (a big question!!!) then I will post explanation of how it was done. If it works it might be interesting to see what ease it might affect. It is very possible that it will destroy the tube itself, so I will dedicate one of my 6E6P as the Pavlovian Dog… If it does work then it is very interesting to see if the effect would be the similar of what I have experience with the DHT last week. On another side it all might open who knew can of worms and to alter the ways how tubes might be operating..

Rgs, Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-04-2008 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 498
Joined on 10-29-2005

Post #: 63
Post ID: 9072
Reply to: 9071
What is randomness?
fiogf49gjkf0d
 Romy the Cat wrote:

 Paul S wrote:
This may also be a factor in the "randomness" capability, which is really only freedom of movement, and not "randomness", per se.

OK, is it “randomness” of “freedom of movement”, the question is not about juts semantics. Since Paul said I have been thinking about is and I have to admit those thought fascinate me. The “randomness” would imply the will of amplifier vs. “freedom of movement” would imply the transparency of amplifier to external source of pace randomness. Romy the Cat


In my mind, there are at least three possibilities, and they must be interpreted by experiment with caution:

1. irregular fluctuations in signal (I will call this "noise") result in irregularities in output signal we listen to and find pleasant; it adds to output signal a quality of "random pace" we like. It should not duplicate itself exactly on multiple listenings.

2. "Noise" acts as analog dithering, to enhance ability of listener to interpret low-level information about pace, emotional content, etc. It should make a low-resolution system sound like a higher resolution system, yet still the sounds will retain many elements of lower resolution, couterintuitively.

3. "Noise" sounds less irritating than IDHT (where the regularity of signal may be more like constantly repeating record "ticking"). The sounds may still be unchanged but the ability to relax and listen is enhanced. Music may sound "less strained" or "more natural."

I look forward to the results.

Adrian
12-04-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 64
Post ID: 9073
Reply to: 9072
Those least three possibilities…
fiogf49gjkf0d

 drdna wrote:

In my mind, there are at least three possibilities, and they must be interpreted by experiment with caution:

1. irregular fluctuations in signal (I will call this "noise") result in irregularities in output signal we listen to and find pleasant; it adds to output signal a quality of "random pace" we like. It should not duplicate itself exactly on multiple listenings.

2. "Noise" acts as analog dithering, to enhance ability of listener to interpret low-level information about pace, emotional content, etc. It should make a low-resolution system sound like a higher resolution system, yet still the sounds will retain many elements of lower resolution, couterintuitively.

3. "Noise" sounds less irritating than IDHT (where the regularity of signal may be more like constantly repeating record "ticking"). The sounds may still be unchanged but the ability to relax and listen is enhanced. Music may sound "less strained" or "more natural."

I look forward to the results.


Those least three possibilities might describe something only if the entire notion of “elections behavior” was responsible for randomness of DHT. Then my “Homework # 4334” experiment will be (or will not be) able to mimic it. There is another “ugly” possibility. This DHT’s randomness might not be due to “elections behavior” but rather due to electrons quality.  I mean the material of cathode or the mater of the coating that was used in let say 1942 was very different then what we use today and therefore the electrons that were evaporating from those old DHT cathodes juts were different type of electrons. If it’s the case then there is nothing that might be done. I know that there is a group of people ho do hunt what they call “period tubes” and who swear that they better.  I would like aside my entire attitude toward to the “vintage sufferers” who persistency demonstrates very poor sound and just would say the following. If that tube from let say 1942 does have “different sound” then it is not well known to me if it was because the contraction or material (under material I imply the tie of vacuum and the rest of the things).

This is why I think it is very interning something like Emission Lab Company that makes the “period tubes” with contemporary production. If they are smart, and I presume that they are, then they shell be able to make even better DHT tubes then what was made 60 years back. The key is to have these tubes properly evaluated sonically in context to the vintage tubes. This will give an idea if the alleged advantage in randomness for DHT tubes derives from the “behavior” of electrons or from their “quality” of electrons. Did anybody heard a sane and without hype analyses of the sound the Emission Lab’s tubes (or the tubes of a similar serous re-manufacture) compare to the sound of “period tubes”?

Rgs, Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-04-2008 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,145
Joined on 10-12-2006

Post #: 65
Post ID: 9079
Reply to: 9073
Randomness and Music's Prerogative
fiogf49gjkf0d
Given enough time (and enough distance), most "randomness" adopts (or appears to adopt) some sort of a "pattern" or patterns.

This appears at the rote level to be yet another variant of the old "musical versus accurate" conundrum.  Yes, the idea of true "freedom of movement" via hi-fi seems far-fetched, unless it is understood that we are speaking in purely relative terms.  Of course I am speaking in relative terms, ie, not all amps do this equally well, to allow the music to go where it will.  Meantime, I still find it hard to wrap my mind around the idea that we can introduce "random" noise that will not eventually be perceived as a constant/distortion  or some kind of limiting or merely ancillary factor.

I certainly do not hear music as "random" just because it is +/- "unpredictable" at a certain level, as it unfolds.  I still think the an amp's ability to "get out of the way" is an important marker in "allowing" music, and I do hear this best accomplished by SETs, and, yes, DHT SETs.  Further, I have always heard this "strength" as the flip side of the SET "weakness", that it lacks the ability to "facilitate" what it "allows".

If I were not so cheap and lazy, I would be trying to get more energy from/in the lower-mids on down, and I would also like to get the "proper discontinuity" between the mids and HF that I hear in live music, where the upper mids/lower treble seem to be kind of "random" in a "spike-y" sort of way.  But I aim to do this primarily with speakers, not amplifier "effects".

Despite my current facination with the ML2, I am very leery of amplifier effects, which I feel take away the Music's "prerogative".

To close with one of my patented full-twisters, I do acknowledge the remote possibility that even an audible "randomiziing" effect of the sort we are discussing here might yet have enough of a desirable effect to offset it, like the ML2's effects still work for me (with good electricity).  To this end, I would at least make a serious try for the AC filament.  Buzz notwithstanding, this seemed to have the "aliveness" thing down, anyway.

Best regards,
Paul S
12-04-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 66
Post ID: 9083
Reply to: 9053
It works, … sort of. The revolution is canceled.
fiogf49gjkf0d
 Romy the Cat wrote:
I have to admit that the idea of the “second solution” looked to me superbly promising. The “second solution” would allow modifying the amount of 2nd and 4th harmonics on a driver without change loading, volume or inflicting of any negative effect to sound. It is not even a harmonic correction circuit but rather a new revolutionary and COMPLETELY NATURAL way to manage second harmonics in respect with volume. I was implemented last night - the “second solution” - well, it did not work, I mean it did not work at all. Sucks!!!
Ok, I found why my “second solution” did not work and I fixed it. Well, it is not that I fixed but I rather used less own moronity while I was implemented it and it stated to work. Did I mention that it shell be a “revolutionary tool” that allow to surgically modify lower even harmonics without affecting anything else and and the most important without affecting the loading. It looks like it does though I did not look deeper how harmless it is. Despite that the “second solution” looks like works I am not so pleased as it does not lead my MF driver to the direction I would like it to be. In fact, running my MF driver up to scale of 2nd harmonics, and the “second solution” also to do it very prissily I realized that my MF channel was loaded perfectly, I kind of knew about it. Adding the lower even harmonics just changed Sound but in my view all in worth direction. So, the revolution is canceled and it looks I have no use from it.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-06-2008 Post mapped to 2 branches of Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 67
Post ID: 9095
Reply to: 8932
Thorsten Loesch’s article about DHT SETs
fiogf49gjkf0d

Here is Thorsten’s very good article about different opinions for DHT SETs

http://www.fortunecity.com/rivendell/xentar/1179/theory/seamptheory/SEAmplifiertheory.html

Quite good writing and quite good thinking.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-07-2008 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,145
Joined on 10-12-2006

Post #: 68
Post ID: 9107
Reply to: 9095
A Beautiful Mind
fiogf49gjkf0d
Lots of good information in there, if one has some idea of what it means in terms of sound and how it might be integrated into a system.  However, some of the guys who are the smartest with respect to circuit design seem to have no discernable sense of direction with respect to music or the sound they are after with respect to their musical objectives.

The Monkey Circuit is very attractive on paper, with basically nothing but wire and the tubes themselves in the "signal path".  Of course, as Thorsten points out, the signal winds up as +/- part of the tank, which basically shifts many of the "usual problems" to the power supply.

It might be nice to use a 45 OT and some sort of comparator for the PS, like the ML2.  It might not be necessary to use feedback, IF you could keep the tank quiet apart from input signal, and if it was kept well clear of clipping at all times.  IOW, unlimited, perfect DC.

Thorsten refers to Chimera Labs' "Kyra" amp, and its PS, but I like the way the same guys did a "no-cap" "mega-tank" similar to the Monkey with their "Axiom" amp.  This one does use (tube) diodes, however, and although they say, "no feedback", it looks to me like there is, in fact, what I call "deniable feedback", where the diodes act +/- as follower/comparitors.  I have not heard it, but in any case they ran their listening tests with "FR" Lowther BH, or similar...

Hard to say what any of this stuff would sound like if subjected to more stringent tests.

Only one way to find out...

Best regards,
Paul S
12-09-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 69
Post ID: 9120
Reply to: 8932
Some summary and conclusions from the first phase.
fiogf49gjkf0d

I would like to overview the content of my thoughts on the subject. I feel that the first phase of my interest in single-stage Milq vs. DHT is over and I can make some observations.

 The subject turned out to be more interesting and more changing then I expected but it was also more fruitful then I expected. It is important to understand that the subject was not about the DHT vs. High Mu tubes as “nl” put it. I have no interest to make general concussions and my curiosity is much more egocentric – I egotistically care about the sound of my Milq-Macondo and frankly less care about compliance of violation to some kind of DHT practice out there. So, what I discovered?

It looks that there are some very interesting characters in sound of DHT tubes. However, I do not know for now how to capitalize on them in the applied sound  as Macondo is multi-amped system and I have no idea at this point  what would be cone and pros  of DHT used if I mix DHT and IDHT amplification with Macondo. I do not anticipate any problems but some corrections of Macondo or Milq operation most likely will be warranted. Admitting that there are some interesting moments in DHT I also observe some negative moments (lost dynamics, lack of clarity, deficiency of intelligibility, lessen articulation, colorations) that I do not like. I think  to move further in the discovery process it would be necessary to built a “clean” brand new DHT amp and to see if the DHT’s negative moments will be gone.

Thinking about positive properties of DHT sound and analyzing the differences of DHT and IDHT some observation and proposals were made how to “tweak” the sound of IDH tubes and to take their performance taken slightly in another dimension. The proposals were tried. One of them was natural injection to the sound of IDHT the harmonic context that is atypical for IDHT. Even though it did not lead to sound improvement in the direction that I would like it to be but the method itself turned out to be VERY interesting and promising. I am planning to experiment more with it and when I have conclusive observations about the ways to do the things and benefits of it s use then I am planning to post all information about it at my site. The second proposal was the randominisation of elections flow and I have to say that the result was instantaneously extremely positive. In fact it was so positive that I feel the method has quite high commercial value as the result were very good and anything like this never was done before. I pitched this idea to an industry-involved friend who might take it farther commercially. So, for a time being the second proposal will not be discussed further.

So, does mine IDHT single-stage Milq, improved by the above motioned “proposal” and become “competitive” to DHT? I have no idea. I do not even know if the DHT would be competitive to single-stage Milq in general sense. I think a “clean” DHT shell be made to take this debate anywhere further in practical and relevant terms. Talking about practical and relevant terms is very important for me as I would not like to change anything in Milq-Macondo. This weekend I was listing a live broadcast of Handel and Haydn Society’s Messiah. The electricity was not bad and the general sound was fine. I turned my attention to “target listing” and was trying to observe specifically the sound of my MF channel, trying to assess what I would like to improve. I did not experience any frustration with the sound as it was; in fact I liked it a lot. There was in it some kind of “super correctness” with no character of own. When sound had to be ugly it was ugly, when it had to be beautiful it was beautiful, when it had to be brute it was brutal, when it had to be gentile it was gentile, what it had to be elastic with flexibility to change of meaning with volume or tone then it was. It was exactly where I need it to be.  So, I do not particularly have any motivations hypothetically to ruin what it is with DHT rubes. Might it be no “ruining” but advancing – I do not know yet, in some aspect it might be. I do not know at this point how valuable will be those “advancing  aspect” and how much effort and compromise I would need to sacrificed to get this alleged or factual  “DHT advancing  aspects”.

So, decided to calm down with this whole DHT saga and to see what happened next. It might be another “cleaner” DHT will come my way. It might be I will build or buy some kind of DHT prototype where I would able to look at the DHT sound deeper and more in context of the whole Macondo-Milq integration. I would like do not do a lot of work with it myself, so I might get some kind of DHT kit that would give a necessary ground for further observations. I was looking for Japanese Sun Audio VT25 and 2A3 kits but they are too expensive juts for experiment. To make them to sound OK it would take another $500-$1000 – too much money and work as if the DHT turns out to be a good direction for my MF channel to go then the prototype DHT will be trashed and a new DHT will built in inside the 6-ch Melquiades.

So, let see if the Second Phase of my DHT curiosity kick in and if it does then let see where it would lead me.

Rgs, Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-24-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 70
Post ID: 9257
Reply to: 8932
Second phase: revising requirement for my DHT objectives.
fiogf49gjkf0d

In context of the recent changes in my playback regarding the electricity and the consequential effects: 

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=9252

I have revised and reinstated my interest in the DHT experiment. In addition to anything I need gain and transients now, so the single-stage DHT with input transformer might not work.

I did not have a line of people with DHT who know in my door with offers, so I need to do it my own. I bought a Sun Audio SV-2A3 kit juts for a sake of prototyping the sound I would like to get and when I found what I like I will implement it in Milq MF channel (if the DHT turn out to be a direction to go).

Sometimes after the New Year and will put the SV-2A3 kit together, with necessary changes and perhaps will convert it to 6E5P-2A3, Milq-type amp. The kit is very flexible, has multiple filaments voltages and multiple primaries and secondarys in on output transformers. In addition to those generic Tamuras I have a couple of my  transformers that are more HF optimized and can handle 2A3, 6A3, 300B, 45 and the rest of them with plate user 2K.

My mild concern with DHT was that they are costly and fragile in live but I have a tendencies to run my Melquiades’ for many hours and days without caring about the live-span of the tubes. Then I figured that in a few days the pilot Mini-Me speaker will be done (my mash saps bed the end of the year) and if it tune out to be good then it might take a lot of dally tube load out of the Melquiades shoulder…

Well, let see what happen next. Who knows if the modified Sun Audio SV-2A3 kit turn out to be an OK full-range amps then I might sell it after I found right MF configuration for myself. In meanwhile, if anyone has any proposal what tube to try in the Sun Audio audio kit’s output stage then let me know. The only condition I have at this point is that I would like to drive the output heater with AC. I think it might be extra fun to drive the DHT heater with good sounding sinusoid. The next step will be driving the 2A3 filament with 44.1 kHz…

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-24-2008 Post does not mapped to Knowledge Tree
JJ Triode
Posts 75
Joined on 09-12-2007

Post #: 71
Post ID: 9258
Reply to: 9257
Tubes for your DHT amp
fiogf49gjkf0d
Romy, I have had good experiences with the Shuguang 2A3C. There are plenty of comments in the Sewer about this tube. They cost about $80/pair and seem quite stable so they are a good choice if you leave your amps on a lot. superTnT.com is out of them now, I got mine from another China reseller, hkadelie.com.

I have also used the Sovtek 2A3, it is OK but a bit dull. I have extra Sovteks if you would like a pair.
12-24-2008 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 498
Joined on 10-29-2005

Post #: 72
Post ID: 9259
Reply to: 9257
Abandoning Milq?
fiogf49gjkf0d
 Romy the Cat wrote:
In meanwhile, if anyone has any proposal what tube to try in the Sun Audio audio kit’s output stage then let me know.
You want a suggestion for a good 2A3? Get Ricardo Kron's (KR Audio Enterprises) KR 2A3. Very rugged, overbuilt. There is no comparison between this tube and all other 2A3's, and I tried many of them. The sound is more dynamic, the timbre is more lifelike, the transients are more accurate.

Does it mean with the PP2000, you will abandon the Melquiades and go for DH SET instead now?

Adrian
12-24-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 73
Post ID: 9261
Reply to: 9259
Will see how it goes....
fiogf49gjkf0d

 drdna wrote:
You want a suggestion for a good 2A3? Get Ricardo Kron's (KR Audio Enterprises) KR 2A3. Very rugged, overbuilt. There is no comparison between this tube and all other 2A3's, and I tried many of them. The sound is more dynamic, the timbre is more lifelike, the transients are more accurate.

The audio Kit comes with Sovtek tubes that are might be expectably bad. The Shuguang 2A3 are single plate that might be interesting. I have difficult time to hear the comments of other about the DHT tubes as they uselessly drool about its LF extension. I so much care less about the 2A3’s bass. It will be used than it will sit behind a 3200 Hz crossover in DSET configuration with an ultra-fast transformer with minimum amount of turns. I do not see anybody comment about the DHT tubes in DSET application… I have those Sovtek tube that she be good to measure operational parameters. I have a pair of new Tang Sol 6A3 from 1944 and a pair of new RCA from 1942. I think they might be a good enough to try for start. If the DHT will turn out a good direction to go then for the channel the will be built-in in the 6Ch Milq I might go for older single pate tubes with thoriated Tungsten heaters. I do not know yeat. The Sun Audio amp will be a good and comfy play-ground for those things.

 drdna wrote:
Does it mean with the PP2000, you will abandon the Melquiades and go for DH SET instead now?

Actually I do not how going for DH DSET would constitute the abandoning of Milq. Melquiades idea was two-stages, both with grounded cathodes amp where the Milq-style biased 6E5P drives output stage. The output tube is not part of Milq idea at all. The uniqueness of 6E5P (besides sonic characteristics) that it can give high gain - output 100V and have pump enough current to push the next tube capacitance. This gives a unique opportunity to swing the out tube juts with one gain stage where mostly people use two stages. There is/was a Milq with 6C33C, 6C41, GM70, 6GL and even with SS output stages. So, I do not see if the out stage will be 2A3 then it will be any departure from Milq. BTW, whatever I m talking about I mean the MF channel only as I other channels in my view perform fine and I intend to keep them as they are

BTW, I have no desire to glue myself to Melquiades or to not Melquiades. Whatever works! Whatever sound I will be able to get with 2A3 of any other DHT it will be competing with what I currently have. I still am not convinced that the DHT will be better solution. It looks that I would like to have more gain at my current MF channel; I would need 1-2 db more or more if I change loading. I do not know yet, it will be seen as time goes by…

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-26-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 74
Post ID: 9268
Reply to: 9257
Single-stage Milq vs. Sun Audio VT-2A3
fiogf49gjkf0d

I was playing lately with the Single-stage Melq and the DHT amp driving MF channel. It turned out that the Sun Audio VT-2A3 was very simple kit and it 2-3 hours to make it working. There is a lot in this kit that I do not like and some revisions will be made in it. Still, even in the “as is” state it is obvious that 6SN7-2A3 and 6E6P direct have very different character. My Sun-Audio VT-2A3 amp is not where I might comfortably talk about it’s sound, I think it will take a week or two to make this amp to sound better in a way it shell. Still, I wonder if those DHT might sound “light”.

Pretend that you are walking on water. You do not need to be a god to do so, you just need to walk very fast, let say 500km/hour, and then the surface tendon will keep you atop the water not allowing you to submerge. So, the Milq 6E6P has a good balance where to lower own speed to 150km/hour and to let the feel to submerge for 1/3 or where to run at 700km/hour not letting the feet to even to indent the water surface. The 2A3 it feels like heavy-sunk time of tube and it constantly run a fully submerged. It has seriousness but it does not look at this point that it has lightness.

Mind you that I am very ignorant with DHT and this is firth amp with 2A3 that I own. So, I need some time to figure out how to cook this tube in order to make it able to do the “lightness” tricks. It is very possible that I need to drive 2A3 with the 6E6P to get the right “acceleration” characteristics... I will be posting my further observations.

Rgs, The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-26-2008 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 498
Joined on 10-29-2005

Post #: 75
Post ID: 9271
Reply to: 9268
Topology and 2A3?
fiogf49gjkf0d
 Romy the Cat wrote:
It is obvious that 6SN7-2A3 and 6E6P direct have very different character. The 2A3 it feels like heavy-sunk time of tube and it constantly run a fully submerged. It has seriousness but it does not look at this point that it has lightness.
I also use the 6SN7-2A3 DHT for my system (except subwoofer). Did you use the Electrocubes for the coupling capacitors? Was the internal wiring regular copper?

The coupling capacitor is critical, of course.

Also, I will say that silver wire, which many people hate: the fact is that it is a better conductor. My opinion is that the silver wire reveals a problem that is creating harshness and brightness from the OTHER parts of the system, perhaps from bad electricity as well.

In my amplifier, careful choice of the coupling capacitor and using silver wire in the signal path corrected the problem of the sound being syrupy like in a dream where you are running is low motion.

Adrian
12-26-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 76
Post ID: 9272
Reply to: 9271
6SN7-2A3 amps?
fiogf49gjkf0d

 drdna wrote:
I also use the 6SN7-2A3 DHT for my system (except subwoofer). Did you use the Electrocubes for the coupling capacitors? Was the internal wiring regular copper?

The coupling capacitor is critical, of course.

Also, I will say that silver wire, which many people hate: the fact is that it is a better conductor. My opinion is that the silver wire reveals a problem that is creating harshness and brightness from the OTHER parts of the system, perhaps from bad electricity as well.

In my amplifier, careful choice of the coupling capacitor and using silver wire in the signal path corrected the problem of the sound being syrupy like in a dream where you are running is low motion.

I did not do anything with San-Audio SV-2A3 amp. I juts built to it original state. The parts in there are crap, including the coupling capacitor, I did not change anything, I need to order the parts to do the change but am not convinced that I will stay with 6SN7. Are you driving your 2A3 right from 6SN7 or you use the second part of 6SN7 as a direct-coupled second gain stage? I would like topologically to stay with 2 channels only as I do not need a lot of gain, quite opposite but  I might keep the 6SN7 – it is a good tube. I might even drop the cap from cathode bias in 2A3 – it shell kill all gain but it is what I might need. I do not know yet.

Can you post or explain the topology of your 6SN7-2A3?

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-26-2008 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,145
Joined on 10-12-2006

Post #: 77
Post ID: 9273
Reply to: 9272
Type Casting
fiogf49gjkf0d
Romy, the 6SN7 with 2A3, per se, even if slower than your 1-stage jobbies, should not be slow in the sense you describe, so something else must be up.

If you get that far, you will eventually want "good" 6SN7s, for color and clarity (yes, they can co-exist)

It's been a couple of years since I tried modern 6SN7s, but they were not good at that time.

Does your amp use sand or tube diodes?

Is it "amp", as in stereo, ar "amps", as in mono?

Best regards,
Paul S
12-26-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 78
Post ID: 9274
Reply to: 9272
Sun Audio SV-2A3
fiogf49gjkf0d

I kind of disagree with Adrian. The wire, the coupling caps, the cathode resistors and many other things are superbly important but it is after the strategic topology is settled. In my view caps, resistor, wire and other things are responsible for the sounds, the minor things, the tactics. The big picture of the sound, the strategy is made by the macro topology. I properly, or I would say sonically-pretentiously, designed amp would sound strategically -properly with any, even with very poor parts and even with not the best assembling methods.

At this point I am not convinced that I will keep the topology of my experimental DH SET, there is a lot of thing that I do not like it.  This amp is Sun Audio SV-2A3. It is very straight forward and simple design.

Sun-Audio_VT-2A3_1.JPG

Sun-Audio_VT-2A3_2.JPG

Sun-Audio_VT-2A3_3.JPG

It is up and running with all default parts, which are very bad I have to say. All tubes are Sovtek, I just took a liberty to put there 3A2 from WWII. I have no good rectifiers and no good 6SN7 and I have order a pair. Still I do not wont to invest a lot of efforts to make this amps to sound better and I most like will go two stage. I have no need for 40 time gain in driver stage. I might get rid of the second stage, make some other changes, or most likely will go with my 6E5P in a driver stge.

For a time being I would like to live with this amp as is for a few days. I drive with it my Tannoy Red full range. In addition I have the channel #3 from my Super Mils is the Injection channel, or a fill range Melquiades amp. So, I might run back and forth two full range amps: 6SN7-2A3/6A3 vs. the 6E5P-1/26C33C into the same speaker. I actually did it today, it was interesting. In a few days the better tubes will came and I might try to change the DHT amp for more sane operation.

So, far the only advantage that I see in my DHT is it boutique quality…

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-26-2008 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 498
Joined on 10-29-2005

Post #: 79
Post ID: 9275
Reply to: 9272
6sn7-2a3
fiogf49gjkf0d
 Romy the Cat wrote:
Can you post or explain the topology of your 6SN7-2A3?
The amplifiers I use started from a kit I bought, the Moondog, so here you can see the basic topology. It is very simple. The first stage here can be eliminated, since the horn speakers are very high efficiency and the grid resistors can be eliminated by using inductors.

Paul is correct that the sound can be very dependent on the parts you are using. I would not make any judgments about the sound. I believe that your impressions are related to the quality of the parts. If you were using, for example, the Kron KR 2A3, you would not be commenting on the sluggish liquid sounds, and it would be very much more competitive with the Melquiades I am sure of it.

Adrian
12-26-2008 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 498
Joined on 10-29-2005

Post #: 80
Post ID: 9276
Reply to: 9274
Topology vs parts
fiogf49gjkf0d
 Romy the Cat wrote:
The wire, the coupling caps, the cathode resistors and many other things are superbly important but it is after the strategic topology is settled. In my view caps, resistor, wire and other things are responsible for the sounds, the minor things, the tactics. The big picture of the sound, the strategy is made by the macro topology.
All these things determine how the electrons move. Both tactics and strategy are necessary to win a game of chess.
 Romy the Cat wrote:
The 2A3 it feels like heavy-sunk time of tube and it constantly run a fully submerged. It has seriousness but it does not look at this point that it has lightness.
To me I understood this to be a concern of sounds and believe it can be corrected on the parts level. I am saying this basically because it is something very similar to what I experienced with the 2A3 kit I started with, but making the changes I described eliminated the problem and gave the necessary "lightness." Adrian
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