Jessie was very right talking about therapeutic influence of audio projects.

I do not know why buy I feel very much attached and really feel personally the various micro events that I are going on with my current 6-channel Supper Milq project.  The idea of a parallel narrow-bandwidth operation is very intuitive and lucrative, the design and layout happened to be very elegant and it is very tangible pleasure to make it happen, at least it is that way how I feel. I am being a consultant and paid for hours even took time off another day in order to go home and to implement and to try on the Super Milq the ideas that suddenly came into my mind – a very dangers symptom indeed…

Anyhow, today is the big day and I am planning to load 5 Super Milqs channels to Macondo and will try to listen it…. It should be interesting….

After many hours and much efforts I have connected the new 6-channels Super Milq to my 6-channels Macondo, with omission of tweeters for now.  I made some measurements and initial adjustments and then was trying to listen it briefly. I did not listen it too critical as it would require more calibration on everything but I was interested about my initial raw impressions. Here are some instantaneous noticeable observations, without order, priority and without any attempts to make any generalizations.

1) The attenuator at Injection Channel turned out to be a total success: very-very-very transparent!

2) I will keep the Injection Channel without any filters and will filter my Tannoys at speaker level. I feel that it is nice to have in house a channel in my Super Milq that will be a full-range Melquiades, able to drive anything else…

3) The volume from single stage amps (Fundamental and MF channels, loaded 15:1) is the identical to all the rest channels – absolutely perfect. The 30K-10K voltage devised at upperbass was all that was necessary to balance all system. (look at the circuit above at provisos page:  http://www.GoodSoundClub.com/TreeItem.aspx?PostID=5207  )

4) I need to research more how I can capitalize on the upperbass channel, since it does not see the Fundamental’s channel drivers anymore.

5) The sound of a single-stage Milq is not the same to the sound of a two stage Milq - they are NOT identical amplifiers sonically. I can’t not say which is “better”, as I hear the single-stage Milqs only in context of narrow-filtered drivers.

6) Since the single-stage Milqs have own sonic signature I feel that I shell review how Macondo should be organized in terms to capitalize the opportunities that those single-stage channels offer.

7) Is any huge difference between Macondo driven by 3-channels Super Milq and 6-channels Super Milq? I would not say so. There are some differences, including some very positive but still are not as huge as I would like to think. From a different perspective the 3-channels Super Milq was perfectly calibrated to work with Macondo, the 6-channels Super Milq is not at this point. I might only presume that when the 6-channels Super Milq and Macondo will be properly integrated then it might be different.

8) It looks that the tube maintenance with the 6-channels Super Milq will be an ugly ceremony….

9) Screw APS PurePower people! During all those upcoming finalizing procedures I would need a stabilized voltage and I would desperately need constant quality sounding electricity. I still have none of them. It begins to frustrate me….

10) The very prominent changes in sound that I’m getting now are from MF and partially Fundamental Channels. With Fundamental Channels is slightly more interesting then it use to be but it mostly because it is now flexible in operation and setting up.

11) The new sound from MF channel is the punch-line of the entire project. Direct coupled to single-stage Milq the MF horn with S2 drives do sound different. The new MF channel has way less granularity and has much cleaner and much smoother sound flow. It is in way very similar to the sound that I was getting from electromagnetic drivers but in contrary to the field coil type of sound the new MF channel has dynamics and it is capable to become very swift and zippy if music is called upon. Still even it’s zippiness a different then it used to be…. is it very smooth but vivid at the same time. I like a lot that new MF sound, but at the same time I have some reservations. My concern is that with introduction of that super-lucrative and “palatable cleanness” the new MF channels lost some bubbleness on sound. I would question if it is good but thanks God I do not need to question it as I have a tool that really sets me free – the Injection Channel. Without the Injection Channel I would most likely have problem with the super clean MF driver but with the Injection Channel I might inject any structure I want into MF sound and it make me really review what I getting from the new MF channel. I was plying a little with MF + Injection and was able to get very-very interesting results – actually capitalizing on the fact of the MF’s new  purity and hipper-hygiene…

12) I would need to roll off the upper knee of my Fundamental Channel slightly faster…

13) The self noise from the 109dB sensitive speakers is = nothing short of phenomenal. All 5 channels emit no noise of any kind, even if I stick my head into the horns. There is no physical evidence that the system is running, beside the lights from the amp – very nice. The 3-channels Super Milq was very quiet but the 6-channels Super Milq took it even further.

14) The 6-channels Super Milq, even it has juts 3 more 6E5P for whatever reason it radiates more heat and warms room much stronger then it older brother.  Perhaps it is because I have more powerful forced cooling….

15) I was genius that I implement in the new Super Milq an ability to turn the amp on and off via a pedal. It is so cool do not bend my fat and lazy body and just to hit a pedal… I need the identical functionally for opening my refrigerator door…

jessie.dazzle wrote:

Upon reading this, I of course immediately want to know your reaction when running the S2 MF channel with the original metal suspended diaphragms reinstalled...

 A very reasonable question. I would like myself to know the answer and am planning to take the S2 with older metal suspension cone and to see how if it behave with single stage amp different. However, I will do it later on and it is not at my immediate radars as it would be satellites and I have a bigger fish to fry at this point (like founding the right operation points for single stages and to make it possible in context of those tubes, resolve some biasing conflicts….. etc…

jessie.dazzle wrote:

This is a really great idea, which BTW should also allow Koshka power up the new amps!

Hm, I never thought that I would make the amp top vulnerable to my Cat to turn the amp on. This is a reasonable concern. Uselessly Koshka do not care about anything unless it covered with fresh tuna let hope that she will not do it and in the worst case I will use a very strong pedal.

Eventually, I had a chance to spend last night with up and running new Milq (no tweeters was involved at this point). As I said before, the major fight was around the MF channel and I feel I did found a good configuration where the MF channel takes advantage of the single-stage amp but do not exhibit the improper volume/harmonic behavior. It is very interesting to see how S2 responses to single-stage amp. I have many observations and I will make them later, when the information will age in my mind…

Meanwhile I decided last nigh to pick a mono recording and just listen some real music, since the Milq/Macondo are already properly balanced.  I took the La Scala’s 1955 performance of Giordano’s “Andrea Chenier” with shining Maria Callas and Mario del Monaco. It played well, though I question if it makes sense to use that caliber music for audio evaluations. 

It was very fascinating to see the MF channel’s reaction to Sound. It has more of that “snow taste” and in a way sounds slightly less “Vitavox-like”. I am not quite sure at this point if it was positive quality and I need to play with settings around the MF channel more in order to get maximum-interesting sound out of the MF channel. What is very positive moment in all of it is that I might work explicitly with MF channel, without affecting anything else. If nothing else and only because of this moment then the entire idea of the 6 channels Super Milq is well-justified. Thankfully, there is a lot of else…

RonyWeissman wrote:

Is it the new Tradition OPT for the MF channel, sorry I haven't had time to follow threads lately? If so I am curious as I need to order an OPT for my full-range melquiades project soon.  (I found someone to build it for me finally!!!) .

Romy the Cat wrote:

If you read the very important post: http://www.GoodSoundClub.com/TreeItem.aspx?PostID=5255 then might understand that it lead to a painful research on the subject. I have ton of data now and many experiments done. If I have time I will upload some notes.

Romy the Cat wrote:

I did not expected that the main impediments in the super Milq project will be the organization (sound) of the filters, particularly the high-pass filters.

Paul S wrote:

Romy, on Fundamentals channel did you leave the 20uF cap at speaker level or did you re-configure that band pass at line level?

Nope, it is hoe it depicted the 20uF cap at speaker level. I see no problems with it is very narrow bandpass that cares no HF. However the interdiction of a high-pass filter at line level, right next to the low pass will create problems. The OPT at that channel is 60H and can care a full range signal.

Paul S wrote:

Are the RC feeds you mention pre-driver or interstage for A, B and C?

Paul S wrote:

Is everything still 1st order?

Paul S wrote:

Can you say already if you have enough drive with 5H on the MF?

Paul S wrote:

No need to adjust - bias on A, B, C?

Nope, in the two stages channels the driver cares 17mA that is very far from critical 35-40…

Paul S wrote:

I imagine "clarity" is astounding.

Nothing extraordinary. There are certain areas where I can report some improvement but nothing revolutionary. It will take time for me to learns how to capitalize on the advancements that I abstained now and how to convert it into more interesting sound….

This weekend the new 6-chenal Milq is not finished yet design-vise but functionally is already “there”. The amp was good enough to play with other 3-chenal Milq. Firstly for the last month I was able to listen full stereo from Macondo…. I spend some time with specific “targeted listening” regarding the nuisances that I was interested in. I made quit a number of exciting observations that will share as time goes by and then I decided to relax from audio and to listen some music. The electricity was not bad and the entire payback was responding not badly. Then, at 2PM, the WGBH kicked in….

In their “SymphonyCast” program the WGBH broadcasted Gergiev leading London Symphony with the 2007 Proms program. Gergiev is not my favorite guy and the Proms seldomly have interesting play but this time it was surprise. Gergiev brought all-Russian program:

Tchaikovsky: Romeo & Juliet Overture
Prokofiev: Piano Concerto No. 2 by Alexander Toradze
Tchaikovsky: Hamlet
Prokofiev: Symphony No. 7

The concert took place in August and WGBH broadcasted live-to-tape BBC recording. The sound was wonderful and as usually SymphonyCast has no abusive compression. The Prokofiev’s symphony was confusing as the Seven should be. The Hamlet was ornamented but boring – I heard more interesting play of this peace. The Second Piano Concerto was extremely appealing - it is seldomly played work and it is incredible complex and difficult. I need to hear it more and I tend to like what I heard; though there were many moments where Alexander Toradze was kind of “lost”. And then the very first piece that LSO and Gergiev played – it was the Romeo & Juliet Overture. That was nothing short of amazing – bold, meaningful and with great respect of own play – the phenomenal performance!

I have to tell that I have heard some new thing in the new Super Milq/Macondo that I liked very much and that I did not experience before. I hope it was not juts an “another good electricity day”…

OK, it took for a while but at this point I have nailed down all design aspects of the new 6-channels Super Milq, and particularly its input stage. I have listen and evaluated all solutions that will be implemented in there; selected, appraised and ordered all ingredients and now I am at a straight finish line with this amp. At this point I know how it will be finished, organized on context of my acoustic system and how it will sound when it will be done.

Here is the semi-final diagram of the 6-channels Super Milq input stage. I said “semi-final” because the values or 2 “red” resistors in the C and F channels will be slightly changed later on, but it will be very minor and will be no more then 20% from where it now. I will make the adjustments on that this image as it is the only drawing that I have and use for the assembly.

A few words about the Super Milq’s final solution.

Lower bass “A” channel: There is no change from what 3-channel. The Super Milq was the same: first order at 65Hz, two stages and 53W dissipation on 6C33C plate at 200V. The coupling cap I dropped to 4uF, did not go for electrolytic and still stay with film cap. I have deseeded do not do inductor as the filter and to say with RC chain. If I found 15H-30H indictor with VERY low DCR (20R-50R) and relatively small dimensions then I might go for it. So far the only inductor that I accept in there sonically was 11” tall and had weight of 25 pounds - I can not fit it in there.

Midbass “B” channel: Everything is straight forward in there.

The Injection “C” channel: The 30K 24-steps L-pad with RN60 resistors and Alma switch is nicely transparent. I do not high-pass this channel at line-level and as a result I have nice full-range Milq amp built-in with which I might drive anything I wish- very convent and I do not need to keep a separate full range Milq around to play other speaker’s drivers that I get from time to time. I can even to connect the second filament on the 6C33C and use more power from the channel. (The OPT has 250mA gap.) I found it very good to have this channel built-in nit to mention that it does very goods job to drive the Reds of the Injection channel. Perhaps now I might let my full-range stand alone Milq to go….

The Fundamentals “D” channel: The first singles stage channel. I use 5E6P in there. To mess-up two closed operating line-level filters was not good idea. Since the channel is low passed I did not detect any negative influence of the caps on the secondary. The channel has also attenuation at speaker level and is used ~ 6db below the MF channel.

The Mid Range “E” channel: This is a purely a shine of the whole project. I use 6E6P-DR as a driver  and  RL filter. Absolutely nothing in capacitive world (mica, teflon, polypropylene, polystyrene) was able to give me the result I got from the RL filter.  Air cap was the best among caps but RL filter was superior to air caps. It does apparently serves the purpose does not put anything in series… So, the RULE is: no capacitors in high-pass if top is wide-open. I shell write more about the selection of the filter for MF in future as it was very interesting journey.  It was exciting to learn that D, E and F channels do not need as lot current as I initially thought and I use 30mA at 200V, which dissipate moderate 6W on plate. The coke I use is Hammond 622ZA in a Co-Netick can. I have also another “alternative” very interesting output transformer for this channel to try….

The HF Range “F” channel: The 6E6P-DR at 30mA connected at tetrode. The filter is second order with Sowter 9858 Pultec MEQ-5 EQ Inductor 420/277/145/108/61/34 mH) and variable air cap. The variable inductance and capacitance allow me to write any prefer Bessel curve against any frequency I wish and I have now much more gain on in tweeter then I need. The driver is tetrode strapped to defeat the insertion loss of the 175:1 transformer and to have more then necessary gain to run the “Water Drop” Tweeter on transition slope, crossed at 30kHz-40kHz with second order. The shortcomings of the tetrodes (loosing of damping, increase of output impedance and so on…) are absolutely not applicable in my case as the ribbon tweeter care less about the damping. In fact if I have a tube with more transconductance then 6E5P-6E6P (30-35ma/V or 30.000mS in Western scale) that has >3-4W on plate and more then 2-3V of bias I would stick it in. I might use something like 7788 pentode only with more power and more bias. If you know any of them then please pitch it to me as to have too much gain on tweeter do not hurt. Do not forget that the chennal will not do “sound” but rather the “space noise”. Still, even what I have now is ~ 12dB more then I need and it is already is very good.

In the end: the layout of the things is really perfect and I do like very much how it fits. I practically (air cap is an exception) do not use any extra wire at all for signals and bias – just the natural leads of the parts. The bias attenuators, after much evaluations, I ended up to use Bourns 83 series that are a perfect balance between the geometry, wirewound multi-turn precision/reliability and sound quality.

http://www.bourns.com/pdfs/8384.pdf

It is pretty much it and not I need to render it in the final implementation….