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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="Welborne"] 1) There are hexagons on the schematics marked with A, B, C ...M. What are these? Are they testing points or they carry some meaning? I can't find much info about these here. [/quote] Yes, the hexagons are test points. Do ...
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So, my two problems have been fixed, I think.First was the issue with the 6e6p for the HF Channel not being able to draw enough current. I checked the bias and it was fine and the potentiometer allowed plenty of adjustment so I changed nothing in t...
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Hi Dima,Thanks for your comments; please forgive the chaos of what follows as I have to rush!
Agreed on all counts - the dc bias point would need adjustment and monitoring; I supposse it depends on how stable the electricity is from the wall; anothe...
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Roman,Well, what can I say.Different parts sound different, like it or not.I agree the topology needs to be "right" first, but once past that you will be surprised just how much difference parts happen to make.However, cogitating about your current A...
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Hi,[quote user="morricab"]Hmmm....I guess I can't really see that unless you are enjoying a particular coloration you are getting from the TVC.[/quote] Nope. On this you are wrong. Based on direct bypass tests the TVC's I USE (that is the specif...
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The very much non-definitive EAR 834P Modification Guide by Loesch Thorsten
Hi,Given that Romy already let the proverbial Cat out of the Bag (pun intended) I think I may have to make good here....
The EAR 834P is a very simple, but rather smartly ...
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[quote user="Romy the Cat"]You decided to go with mA or are they mV against 1R resistors?
I prefer the second approach personally and I feel that I can moderate the quality
of resistor and I can’t moderate the quality of the milliampere meter coil....
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[quote user="cb"] 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 adjust voltage to 0.0mvdc, I get a reading of plus 0.4vdc. This is with VR1 set at maximum (...
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Thanks for the link, Romy.Very interesting.I need to run the numbers for 150 Hz, both high and low pass, 2nd order.Cement type resistor? Mills have gone to the dogs...Variable inductance OK (it might be handy...)?Have you tried s...
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Work has been so crazy busy all last year and through these strange times right now that I have not been having any time to think about the audio project let alone indulge in advancing it. One DSET/Macondo has been playing mono and I have really bee...
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Amir,R2R Discrete, means it uses the good "old" resistor ladder instead of a DAC chip. There is more info here. But you can find more around the internet.Cheers....
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Positive voltage supply does nothing but balance zero volts at impost. You can go for "pure" implementation and to get a dedicated PS of you can take voltage from any positive voltage, let say from B+ of a driver tube, use voltage divider and drive w...
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Sorry Romy, I was not clear enough, but the resistor that I am questioning is in the Fundamentals Channel (not the MF Channel as I believe you referred to in your previous post) between the OPT and the S2....
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Hi Romy,I've been reading the 6e6p-dr datasheet and it seems as though pin 8 (a shield) is recommended to be tied to a lower negative voltage than the tube cathode. Have you bothered or experimented with this? This is no problem in the DHT Channel ...
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Finalizing parts ordering for full range Melquiades and I have one thing with is unclear to me, the plate to grid resistor on the 6E5PIs R23 50R is this correct ?There is another R23 in the driver power supply .http://www.goodsoundclub.com/PDF/Me...
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[quote user="jessie.dazzle"]Is this because of the way you are driving them?When testing my one completed mid-bass horn (AK151 into 40Hz Exponential with 8" throat), and powering it from an amp that drives everything from upper bass to HF, the output...
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Ok, I have figured out why I have so extended bandwidth over 73kHz for my tweeter. I forgot that when I measured it I had the LPAD wide opened and in this configuration the parallel resistor is 20K and series is shorted. So, in that case I had just o...
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[quote user="Chirag"]The 6E5P is an interesting device (I did some research after you dropped the "tetrode" hint and bought a few :-)), but the bias scheme with the OA2's is still incomprehensible to me. [/quote]Ok, I will try to explain.
The...
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[quote user="nl"] Gordon Rankin of Wavelength Audio did a series of one-stage DHTs with a step-up transformer input about ten years ago. I think they were called the Mercury series. By all accounts, they sounded good, but of course had limited gain, ...
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[quote user="cb"] 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...
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Excellent! I don't use step-ups and I always tie signal earth to chassis earth through a 10 ohm resistor at input.Brian....
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[quote user="Axel"]OK, this is useful also, in that you have not noted a "pattern" as you say. My point is closer to your suggestion, that I do change cart --- and sometimes buy new ones, B U T I do not buy other SUT (at least I try to avoid it). I'...
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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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I have no doubts that it will work but I would like to understand HOW it works.
The objective it to have first order filter, of cause not the filter where capacitance do high-pass roll off but RL. In RL filter there is not reactive elements i...
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Romy if you feel that you are not loading the tubes enough put a 16ohm power resistor in parallel w the S2. this will cut the load line in half. It should be less wiry and stronger more weighty sound. Obviously you might experiment w values to find t...
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It's too late to be doing homework, but I seem to remember that mercury vapor tubes will handle serious voltage.Just put the resistor right on/under the pin.(damned collectors...)Best regards,Paul S...
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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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I haven't played with the loadings yet, as I'm still in the deep woods of the assemblyand a hunt for an intelligent SUT. But the primary loading scares mewith it's super sensitivity to the resistor quality, value, etc.Anyway, I'm somehow optimistic t...
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Alex, a cartridge loading has no “right” absolute value, it has of courses a certain fork of right values but to loading of a cartridge up to one of a few Ohms would be depended from many parameters, in some instanced unexpected. In my hands, used as...
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Welcome Sean19, Another member should correct me where I am wrong. There should be some tweeters that just start emitting in their proper frequency range and do not need a crossover. They might need a resistor so that they are volume balanced to ...
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