One of the most interesting outcomes of the Milq conversion into 6 channels is the impact it had to it MF channel.  The tweeter is a separate subject, I still work on it, I know how it will be done but I did not hear the final result. I would like to report something special about fundamental channel but there is nothing special about it – it sounds as it was before. I have with the dedicated amplifier some flexibility to play with it but basically it the same. The upper bass not has own dedicate amp with 14dB superfluous gain and I can theoretically to put in there any driver I wish, not necessarily as crazy sensitive as Fane was. I might do it in future if I find more interesting sounding driver then 8M. However, the sound of MF did change quite interestingly.

If you read above then you know that my primary concern was the inappropriate harmonic changes with volume when a channel was high-passed and with opened top. After many experiments I summarized that it was related somehow to the filtering capacitor.  Not necessarily a capacitor as a “better or worst sounding capacitor” but rather a capacitor as a topological entity. A serial filtering  capacitor is not coupling of power supply capacitor and it is not charged by DC, therefore it’s dialectic is not polarized and it gets re-polarized with every electron of AC signal. It usually impacts sound statically, injecting permanent  coloration, and I never seen before that it had dynamic impacts fluctuating with volume. The Air cap was better solution it had no re-polarizing dialectic. However, the RL fitter was juts way out there. It immediately did not just answer all questions but make the question do not need to be asked.

The S2 driver with the RL filter sounds exactly how it sound without any filter at all, in fact it sounds slightly better then without any filter. Perhaps it has to do with unloading bass from inductance-challenged transformer but I did not hear any distortions what I drove the 4H MF transformer full-range. So what is so special with the sound of the new S2 channel? Here are a few factors:

1) Less “bad granularity” without loosing of the “good granularity”.

2) Way cleaner upper region, though without the “bad granularity” it might feel in beginning that it has “less HF extension”

3) The awareness of the driver about the full range or something that I call the “neighborhood watch effect”.

This last entry should be explained because it was EXACTLY what I was looking to get from my MF driver. When I listen my stand alone S2 now it reproduces above 1K but it has awareness about the whole spectra of music. It is not the bottom knew response and but rather some very long acoustic-like harmonics that make the driver to reacts upon the events that are outside of it reproducible range. If I have a bass note that shell not be auditable via the MF channel then this note of course is not auditable but the MF channel still creates a “perceptional event” that indicates that there is a hole in the music that should be filed with sound or with mental extrapolation.  The channel with capacitive filter does not do it – it masks out events from the non-reproduced regions. The driver in the way acts as a pointer that shows off what the others channels shell be and how they shell sound. Of course it is necessary do not subtract from it the S2 it’s speed, the phenomenal transient capacity, the “absolute tone” and the vintage ability “to go boiled” with tone when it necessary.  Hey, if the second channel will do the same then it looks like I will be able to play the brutal London Symphony’s valve trumpets and soprano trombones as they should be played…

I am becoming a more satisfied Pussy with my 6-chennal DSET project…

Paul S wrote:

If you have the Mercury SR2-9013 35mm master Dorati/LSO Nutcracker, that might be a treat

Hate that performance.  Dorati did not play Tchaikovsky appropriately. Each and single Dorati’s Tchaikovsky piece sound to me like a shopping in IKEA…

Paul S wrote:

Now, how to get 180 phase and 12 dB slope without a cap...

I do not think it is necessary with tweeters as the job of the tweeter is to inject nose not sound, unless the tweeter crossed too low, and in such case the selection of a ribbon tweeter was a mistake most likely.

Paul S wrote:

Who knows how many times the signal can be "re-constituted" via inductors?

I do not think that any re-constitution takes place. In a cap the signal that is in the filter zone of transparency flows still on the capacitance of the devise – it has no physical contact between input and output and the cap acts s a frequency depended series regulator. An inductor, however, acts as a shunt regulator, shorting the frequencies and the band-path of the RL filter flows directly hardwired to the load.

Last nigh I spend a couple hours to listening this thing. Since the amp is done in design phase and the final parts are still in order I can not finish it and close up – it kind of frustrating… Still, it gives opportunities to listen it knowing that it’ll be “like that” when it will be done.

I have right channel that is absolutely untouched old 3-chennal Melquiades with “old” Macondo. As the left channel I have the new 6-chennal Melq coupled with the new Macondo. Of course I feed them with the same mono signal and it gives a very good illustration where I have gone in term of Sound with the 6-chennal Melq revision.

As I said before the flexibility to write any sound I wish with 6 active channels is very appealing. Also, as I said before the top 2 channels on the new Milq/Macondo are the most interesting.

To best describe what the new MF channel does would be to imagine paintings that were painted by brushes of 8mm and 1mm. The narrower brash allow going into greater amount of details, if there is a need for it. Sonically it works very interesting as the channel goes into details not always but only when music calls to it. When it necessary it still paints the picture of Sound with the sweeping stoke of the large brash. Ah, the wonder of the 6E6P!!! What is very important to understand is that this new higher level of “resolution” has nothing to do with the idiotic illusion of hyper-resolution, escorted with harmonic castration, as the most of the nowadays manufacturers do (Kharma/Avalon/Magico and many other). Quite in contrary - the new Milq/Macondo MF channel has more dominant low order harmonic tail then the old MF channel, the tail that stays with volume. At the very same time the driver despite of the long harmonic tail runs across the dynamic range even faster then before.  Quite a positive result! What is also is very important to understand that the new higher level of “resolution” has also absolutely no Spectral-like HF dithering where the upper range hyper-structuralism is perceived by audio-Morons™ as  “quality”. The new MF channel goes up very forcefully but very pliable with grace and elegance. When the channel hits it’s limit (dynamic or response) it does not dive in convulsions but just crumbles with modishness and without calling to itself. It is in way reminds me the sonic fading of my channel armed with electromagnetic S2 driver but the new MF channel fades from the Sonic heights that the electromagnetic never ever approached.

The HF channel with the new Milq is completely different story and they are a totally new page of HF evolution compare to what I had before. I do not think I even heard that type of HF. It will be a separate set of the observations in the “Water Drop” thread when I feel I am ready.

I was playing Bach’s harpsichord concertos last nigh and I come to a very interesting observation that my Injection channel works quite different with new Super Milq then it was with old Super Milq. I was driving the old Macondo from the amp of the new Super Milq and confirmed that it was not because the differences in amplification. The new Milq/Macondo has subjectively higher dynamic range and height level of tonal saturation. That makes the colorizing-dithering effects of Injection less beneficial with the new Milq/Macondo. I still see the Injection benefits but I apply it now much more conservative then before – a very positive thing from my point of view. The good thing also is that the new Milq/Macondo’s in it’s new level of tonal saturation do not dive into the “Van Gogh colors” as my Injection Channel with Reds tends to do…

It looks like the new Super Milq/Macondo idea turns into something very interesting. I really would like see it all done and the amp is closed up and permanently installed. In reality I certainly do not know what is responsible for the positive upper range advancements in the new Milq/Macondo tandem. It might be the elimination of high capacitive 6C33C, it might be the use of the single stage amp, it might be the use of different output transformers, it might be the use the small topological changes that were made in there, it might be the use of different type of filters, it might be the use of different rectifiers and some other changes in PS section. If I were in audio business then I would catalog the changes and try to capitalize on them but since the success in audio for me is Sound in my listening room then I less care about the reasons of the result if the results are satisfying.

jessie.dazzle wrote:

While reading of your progress on the 6 channel amp, I was thinking ahead, and how I might approach the building of such amps as separate projects for each frequency band (separated physically as well). In my particular case, this would be in the interest of keeping things simple, but also to leave the ML2s to run the rest of the system while building/evolving the new amps. The idea being to remove the ML2s one frequency band at a time, and compare one addition (one frequency band) at a time against the ML2s.

Well, I understand what you are trying to do but I see some problems with this approach. I the way how you approach it you will not have optimized paths for input stage and very much might end up with 6 input cables. Alternately it might be done as 6 plug-in sections, using high quietly Tektronix knife-connectors… If so then the PS and everything else should be packaged with plug-in objectives.

If I have an aim to build an unknown DSET for myself then, knowing what I know now, I would chose for following approach:

1) Build one prototype of full-range SET channel, powering it from any old good lab power supply. If you do not have it then get on eBay for $200-$300

2) Deeside for yourself if the amplifier is worth pursue and delivers the results that I would like to see (sound, power, gain, measurements, stability, operation, parts etc…)

3) Built a power supply for whole DSET, calculating the power for 6 channels (with 30%-50% spare power) and use multiple taps (100%, 110%, 120%, 130%, and 140% on primary for plate transformers, enabling me to add channels to this supply. Do not under-estimate the thoughts about the PS to amp interface – it is VERY important decision.

4) Convert the built full-range channel into a first DSET for upperbass/lover-Mid channel powering it from the DSET power supply.

5) Order the output transformers for the rest channels and having thier dimensions begin to think how the whole DSET will be package chassis/chassiss – wise, fitters-wise, layout-wise etc…

Above is the HF's high-pass filter for the "Water Drop"

I had never seen anything like that. I like their looks. Do they "sound" as expected? I'm fascinated for your efforts with your system. I think I don't have the endurance to go throughout all that, provided I had the time, space, resources and knowledge, which of course I don't have. Good luck Romy, I hope you get where you want to arrive.

drdna wrote:

The question in my mind Romy is: why?  I will be interested to hear your comment on what your goal was to learn about your system in introducing these and what the results are.  After the extent to which you have described the sound of your system, it will be very instructive to hear your comments. I have toyed with the idea of using these for RIAA circuits in a phono preamp, since the required pF values are appropriate and they should offer minimal distortion.

Pay, attention the Melquiades nowhere uses the “bad-type” (location) capacitors. Wherever the circuit is called upon such a cap the amp uses RL filters or the caps with no dielectric (air, vacuum)

op.9 wrote:

Could you help me understand your biasing scheme with this version? I thought I understood the original Milq circuit - but the only channel that looks like that to me is the D channel. I don't get A and B at all! what is the 50 ohm resistor doing? is it just a grid stopper? I assume you can adjust bias and 0v at input in each stage - but don't the two red legs (on channel B for example) work against each other?

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=5533

…and it would be totally different subject.

Let look at the Super Milq’s input just from purely electrical perspective. The basic premise is to get rid of a DC blocking capacitor at input. To do it we pit a series dose ohms resistor and then apply a contra-collage on another side to keep the DC balance at input at zero volts. Then we need to put at each channel own filter.

Here is the initial filtering idea.

I intentionally kept all drafts on the site to show progress and how one thing flew into another. Eventfully the series capacitors were replaced with RL filters and it make too many series resistors in signal pass, so the objective was to combine the filtering and biasing duty of the resistors together.

So look with what we end up:

Channel A: Has RC (substitute for L) filter at input and the 30K filter resistor is used as yellow biasing resistor. Look at the Draft 3. R14 and R27 are the same resistor and if so then we do not need R17 (red), the purpose of Red resistors is apply positive contra voltage on the left side of bias resistors but in the final draft on the left side of 30K resistor there is a common B+ voltage share be all channels. Surely, since we have much less positive voltage “sipping” through the new bias resistor (30K is more then 12.1K) then we need to apply much less negative voltage to the grid, or to increase the value of greed resistor. The 50R resistor is grid stopper; it might or might not be there – does not matter for THIS circuit. (The need of grid stopper for fast tubes is another subject all together)

Channel B: The identical story with the Channel A only instead of 30K series resistor we have a voltage divider that from a prospective of filter/bias is the same fixed series resistor. Pay attention that of I can the cable on the left side of the divider, disconnection the Channel B then I would need to change value of the Red 402K resistor at the bottom of the image as the total balance of positive (coming from 402K resistor) and negative (returning back from each channel) will be changed.

Channel C: this is practically standard Milq configuration with L-pad at input – there is not filter in here. You would ask me why I did not use the same approach as I used in Channels A and B – getting rid of Yellow and Red and letting voltage to pass via the attenuator to common positive. The reason is because my L-Pas is laden type, what has constant input impedance and variable output impedance. So, the circuit balance the 0V dc on left and right from the L-pad, making the channel DC do not care about the L-Pad. If in my L-pad I would flip not 2 resistors but 4 and the output impedance was constant then I would employ the same approach as I did in the channels above.

Channel D: This is quite complex. We can’t used the approach as above as the DCR of filtering coil is too low (250R) and the negative bias voltage shorts itself to ground via the coil. So, we need here a fill scale biasing Yellow resistor to keep the tube happy. What happened at left side of the Yellow resistor? Some voltage comes from positive bias, via 36.6K resistor and across 250R of coil to ground. So, why do we care, we juts  adjust the voltage of common positive bias and it will be it.

Channel E: The RL filter, the situation is identical to the Channel D. It might be a concern that I have we have too high series resistance in a grid chain. In practice is dos not sound as HF-challenged. That impedance with Miller capacitance of the 6E5P makes ~ over 100K low-pass filter … not so damaging for a fast, oscillation-incline tube.

Channel F: It has input cap that does not transmit DC, so we should not vary about anything and juts run one green resistor with negative bias supply. However, some voltage drift via coil to ground, passing through the L-Pad with variable output impedance… Eh, Not good! So we need to put a Yellow “bias stopper” into the game and to get 0VDC on the left side of the Yellow resistor. Then positive will not flow to coil because it will be blocked by the cap and negative will not flow anywhere because it balanced by red resistor. This way flipping the L-Pad affects nether bias nor impedance. Not that the L-Pad has constant input impedance against which the CL filter is written (it is Bessel). It was very important and a change if the attenuator impedance would lead to change of crossover point and subsequentual throwing the tweeter off the time aliment.