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| Romy the Cat's
personal site dedicated to advanced audio and evolved music reproduction
techniques
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[quote user="Romy the Cat"]3) There is a mistake in Milq circuit. The B+ of the driver stage has almost insufficient amount of critical inductance. It was because I drew the circuit having the Super Milq in my head where the PS was feeding 3 stages a...
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Hi all ! I thought about this resistor bias idea that Chris proposed , and found some some problems here . One of them discovered Chris himself - it is a big serial resistor in the grid chain , and it can cause not only HF rolloff ( it isn't a big pr...
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The 6sn7 is a fine amplification tube for use in preamps or gain stages, but it has way too high of an output impedance for driving power tubes. This is my personal preference. It also depends greatly on the topology. Maybe George u...
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[quote user="hoan da ox"]Hello to all, After following the comments of Romy for some time (have learned a lot, thank you), I would like to ask a question on this subject.This circuit is built with resistors, diodes and capacitors. Could someone elabo...
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[quote user="deemon"]Do you mean a battery bias , Brian ? We didn't try it because of 1 V bias voltage - I don't know if the battery with this voltage does exist . I know only 1,5 V and 1,2 V cells ...... maybe using some chemical reactions we can ob...
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thee srp in Zarathustra is cathode bias, melq is grid bias. If gas biased the srpp it would no longer be the circuit in zarathustra. what would this do to sound i have no idea. The function of the gas tubes in melq are not only for providing bias. ...
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Thanks for your help Romy. Have a look at this (barely legible) sketch so we have a common reference:This is Channel B First Stage bias circuit. All is identical to your published schematic apart from R9 which I had to increase to get the other sta...
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And I do not mean this as a criticism.I had for some time an "original" Music Reference RM9, which was made by another well-educated genius, Roger Modjeski. The RM9 was AB PP with adjustable bias and feedback/gain, with 6DJ8 drivers and a ...
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Hi to everyoneyears of reading but never subscribe and post to forumI see that Zarathustra circuit and i m very interested on the first SRPP stageCan someone point out how to implement Melq Gas Bias on that SRPP circuit?I would like to implement a li...
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[quote user="anthony"]I did finally manage to get a day and a half to make the second DSET operational but it refuses to bias correctly. I've traced the circuit a dozen times, checked component values, tried to find shorts, checked cap polaritie...
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Grid leak bias is not reliable itself . Grid current is very low and grid resistor is very big , the circuit become very sensitive to all destabilizing factors - capacitor leak , humidity , temperature . And when we apply a big input signal to t...
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This thread has been pretty interesting overall. I've read most of it and would at least like to provide some feedback on the technical side of designing with the 45 and 2A3 DHTs... at least from my personal experience. A few years back I decid...
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[quote user="op.9"]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...
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Hi Romy
I have a mono completed full range Melquiades and another only with the bias circuit hooked-up.
The bias voltage I get on the 6e5p is around minus 4.4v on both the circuits. This is with the inputs shorted. With the inputs connected to adj...
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[quote user="op.9"]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...
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Since I know about a few ongoing attempts out there by different people to build Melquiades I would like to share with some of my observations regarding corrections, simplification and possible modifications of Melquiades amplifier.
Obviously you ha...
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N-set, I am not the one to double check your mathematical solutions, that's for sure. I wonder if in practice the curve values here are effectively tied to variables? I like the Chimera idea, but it has no "locked curves" to contend with, and it us...
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N-set, have another look at the Chimera "bias", and the sophistocated way the diodes effectively buffer the gain stages, also the way the caps are staged over the tiered ground planes. Also check where the Ls are with respect to the signal. Perhaps...
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N-set, I am sure you realize by now that I do not properly understand "electronics". I see the "diodes" in the Chimera circuit as a sort of "active" bias that is also dynamic proof against blowback/ripple to and from the tank, at each of three "...
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Romy,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 doin...
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He did note that the ML2.2 uses a different OPT, and also that it uses "less feedback" than the ML2.1 (which AD owned for several years). I wonder what this means, "less feedback"? Why would Lamm mess with that very effective scheme? Does he just ...
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Yes, you are right, the voltage divider from 6.3V across 47K and 10K resistors shall give not 0.9V but 1.1V. However, the numbers that are in circuit are not something that I saw in my dreams but the actual numbers that I measured. I might presume th...
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I Forgot they did this. I only have experience with se driver stage. You would remove r3 and c1. change r2 to 10k and put the bias voltage from the gas tubes across it. I would try just regualar zaruthstra srpp circuit first. Like do you know it wi...
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Can someone help me to calculate the input impedance of the 6-chaenal Milq?It is cannot be measured as a regular DC impedance as it is affected by the active impedance and the by positive and negative voltages from the bias supply and the bias compen...
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Actually I do not have the instability issue sorted out completely...I'm talking about circuit instability now, not the tube instability. Let us imagine all tubes are rock stable.As I see it there are at least two major sources of instability, in the...
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I like having a center-tapped filament winding for flexibility. First, you can use a traditional approach on hum balance (what you have now) or use a slightly different approach. I use the center-tap as a fixed DC balance (cathode bias resistor solo...
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(Romy feel free to move this post)[quote user="Paul S"]N-set, I understand you do not mean to hijack the thread with the Axiom, so I actually tried to make generic and/or thread-related observations. I don't know the 6E5P, but generic issues with sp...
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I made experiments running HF filaments from dedicated Hammond 6.3V transformer vs. lifting ground on my 6.3V IDH filaments. I did not listen Sound but rather measure the noise – the result was identical. In the best cases I was able to get 0.63m...
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Adrian, Fair enough... it's not about power or gain in your case, just making it sound as clean as possible. Well, if you go back to my earlier post on findings, I list the basic operating values. Just to recap them here:Plate supply ...
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First, Adrian, Thanks for your feedback on the newer designed 2A3 tubes... very interesting. I've looked at all 3 of these brands before but have not as of yet purchased any (I have a large collection of 45 and 2A3 of various NOS US brands...
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