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| Romy the Cat's
personal site dedicated to advanced audio and evolved music reproduction
techniques
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Wow! I did not realized that almost 4 months have passed since I wrote last.
Quite a few things have happened the last 4 months that I have played with the 6C33Camp/preamp combo. I have tried at least 3 different vendors on the Ulyanovsk type, the ...
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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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Generally the 105V gas
tube are the best and the most stable gas tubes and if you are willing to use
them then it would be a good idea. You need to recirculate the whole bias
securely to do so and it is tricky. It is not so hard to figure out how ...
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Hickok Model 600/600A/800/800A/533 Tube Tester Quick Reference Instructions by Daniel Schoo from Illinois.
AC LINE ADJUST: Push P7 and adjust the AC line control until the meter pointer is at the LINE mark at the center of the meter...
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Ok, I made some further experiments driving this time my S2 driver from Milq DH DSET. The hell of the sensitively - it was too much. So, I went for 4:1 inner-stage ratio. The result was very successful and the amp looks like was able to get more...
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Well, they technically not Lpads but juts regular attenuators
even though they connected in “protective mode”. You can go with stabilized impedance
to maintain the high pass filter over the coupling capacitor to work properly
but I do not feel it ...
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[quote user="Romy the Cat"]Well, they technically not Lpads but juts regular attenuators
even though they connected in “protective mode”. You can go with stabilized impedance
to maintain the high pass filter over the coupling capacitor to work prop...
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[quote user="Romy the Cat"] That is very good approach in my view. The
problem is in this approach that you have to have high sensitively speakers
that you would be able to use with that test full-range Milq. The behavior of
the Full range Milq wi...
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Romy,The normal bias for the Golden Grid tube for 200V Plate at 200ma is about 70V-80V for the good tubes, the bad tube read 0ma at this bias, when drop to -30V it start reading some current, but can't get to 150-200ma current for the SE amplifier.Th...
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[quote user="Romy the Cat"]Celsius, I think you do not take in your equation the input voltage. If you bias 6E5P with 4.1V then it can pass 4V with no feedback. Since the tube has under normal circumstances 33 times gain then you have 132V RMS from ...
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Hi Romy,Further to my earlier message, I've measured the bias voltages for the driver tubes in all Channels.A -4.3V not adjustableB -13.82V not adjustableC -4.8V not adjustableD -4.2V (ran out of potentiometer travel...may have to adjust a resistor)E...
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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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Was talking with various audio people about the 6C33C I was amazed that people are so clueless about this tube. The people are so filled with some foolish prejudges and faulty notions about 6C33C that I deseeded to put together a brief “6C33C user ma...
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The issue I see is that of intermodulation distortion on the biasing of the output tube. It will effectively change HF operating point per supply ripple. Easy to understand if one imagines a gross ripple of 50V. Same thing happ...
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Romy, No easy drawing program available this second (traveling for 3 weeks) but I can send you a simple schematic in PDF if you like via email. In any case, to adapt what you have already have to the split biasing, just remove the cathode bias resis...
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[quote user="morricab"] You are also right that to get everything you want from an output transformer requires a VERY expensive construction and top materials. However; even an expensive transformer is no guarantee of success. [/quote]
Sorry t...
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Thanks again, Romy. The bias pots, mechanically, are just as you observe.I supposed that the extra current draw during burn-in was normal for the ML2s but I had not noticed it before, since I typically do not bother to check or t...
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[quote user="Romy the Cat"]Anyhow, the problem is not with Ken Chait or Lamm owners but in the totally foolish expectations that 6C33C might be matched. Well, if you do burn the 6C33C for 50-60hours and do match it by gain, by bias and by currant the...
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Post #83:
Bias
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by
G
on
2018-04-03
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Hi Romy
I have built a Melq prototype and need some help with the bias.
This is my first tube amp build so my understanding is not great.
All parts values were used as per the 4.4 schematics. Rectifier bridges were built with Infineon SD...
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I speak with people, receiving emails, read others comments here and there and I constantly surprised how the accidentally obtained and unreasonably interpreted data become a wide spared audiophile myths.
For instance there is a strong believe, wit...
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[quote user="floobydust"]Running the higher B+ voltage (350 volts) with a 1K cathode bias resistor and the 2.5K load results in higher distortion than the text-book operating point, which is B+ of 300 volts and a 750 ohm cathode biasing resistor and ...
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Ok, once I got pin 8 connected to pin 1, the curves came out straight. Here is the true pentode plot at 200V screen, 0.5V/step:[img]http://www.hagtech.com/blog/images/7788-04.jpg[/img]And here is my new data sheet plot for triode mode:[img]http...
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The greatest thing that happened to my Yamaha B2 amp was the fact that I got rid of my MiniMe ported bass section. The MiniMe is truly nice now and I operate in the highly desirable not annoying status. That all made me to pay more attention to w...
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Adrian, Romy, et al, Okay, I don't take any of it as an attack... so none of that bothers me.... I'm fine with it... again, it's a view on what you heard based on your test scenario, nothing more and I certainly welcome the review. Now tha...
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Melquiades condition (both cathodes heated)Plate Voltage 220vBias Voltage -80v (-110v puts the working point in a ridiculous place on the curves I have)Plate current (according to the curves) 165mA approxPower Output 15.5 Watts2nd Harmonic ...
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[quote user="ml8"]...but resistor between screen grid and plate, to my hearing, makes sound slightly unnatural, especially in highs.But this may be not true in your case (i didn't try to use this resistor with 6E5P, only with other power tetrodes), s...
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Now I re-listen all the things the we try to measure. To surmised everything I have to tell that Dima’s way to looks for optimum operation point of the tube (setting balance for voltage vs. current sufficiency) turned out to be very successful as I d...
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I did try it and it was very bad. The Bias Channel did not affect imagine but only made soundstage wider, which was not my intention. Along with the widening of soundstage it made a LOT of other very negative impacts, namely increase compression, mad...
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Adrian, Romy, (Dima), First, I most certainly agree that the textbook operating point for the 2A3 is not optimal and can be improved on, hence my own design from a few years ago. If you are sticking with a 2.5K load, you will simply not ge...
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Yes, it is imposable to have + 0.4V on the grid, 0.0V at input, with R5 resistor in place and the gas tubes outputting +150V and -150V. My apologies, I meant to say I have minus 4.4v on the grid with the inputs shorted. Then I unshort the ...
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