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rjp

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About rjp

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  1. That does not appear to be a HIII in the picture. The grill is too far set back compared to mine.
  2. Hey, beautiful setup! I see you are running a PAS preamp and a Dynaco ST70 based poweramp. I have the same setup with my Heresy IIIs. The PAS 3X is a very recent addition for me and I'm not sure what I think of it yet. How do you like yours? What benefit do you feel it bring to your overall sound? Would love to hear your opinions. Thanks.
  3. rjp

    New VTA ST-70

    Why do people think gain with wire is best? I mean, we're talking tube amps here. It's all about signature and coloration. The "best" is your favorite color
  4. rjp

    New VTA ST-70

    I tend to agree. Every amplifier has a characteristic sound. It seems that the question comes down to do you which sound you like better, the preamp, or the power amp? From what I'm reading it appears most of the big money is invested in preamps to get a super great sounding but very fragile signal, and then the power amp is just about making this louder and strong enough to drive speakers. So using a path into the power amp that is as transparent as possible only has value if indeed the power amp is what you want to hear.
  5. rjp

    New VTA ST-70

    Fair enough. I meant they were 100% out of the signal path. I wonder, can the additional path to ground make any difference in the sound? The attenuator Bob supplies is 100K. The VTA board itself has an input impedance of about 270K I believe. So the (full volume) input impedance at the RCA jacks with the stepped attenuator in place must be down to about 75K. The output impedance of an iPhone 6S is 3.2 Ohms, so even 75K seems huge in comparison. A higher resistance attenuator could be used to keep the input impedance up, but that would potentially introduce another more significant problem. Loss of high frequency content due to Miller effect. I assume this played into the 100K choice.
  6. rjp

    New VTA ST-70

    Technically speaking 100% correct. Zero NEED for a preamp. But preamps (good ones, I'm told) add a host of magical musical qualities and gonads (a.k.a., dynamics). I have recently been involved in extensive research and technical discussions on this matter, and though I could uncover no good technical reason for the preamp, I just bought two of them so I can find out for myself if they really make the VTA70 sound better (compared to the 21-step attenuator direct approach). I purchased a Dynaco PAS 3X from ebay and a VTA SP12 kit from tubes4hifi. I am really looking forward to building the SP12 kit! If I realized I could get the basic board for under 200 bucks I would have skipped the PAS option. Well, it will be fun to try both. I'll keep the one I like and sell the other. They will both be in super amazing condition when I'm done owning them. So...I intend to be in serious preamp mode shortly You know what's the dumbest thing? Calling a simple potentiometer or stepped attenuator a "Passive Preamp". Well, actually, that's just a misnomer. The dumbest thing is paying 800 dollars for "really good ones"
  7. rjp

    New VTA ST-70

    Ok, so the amp you have is a Bob Latino ST70. Most people call it a VTA70 (Vacuum Tube Audio) to distinguish it from the original Dynaco ST70. This is an amp I am very familiar with. The input level required for full power out is 1V rms. I bench tested mine and was able to get 38W rms per channel before I started to see clipping. This was with both channels driven into 8 Ohms at 1KHz. The input voltage required to achieve this was just slightly over 1V rms (i.e., 1.4V peak). Any modern input source can easily provide the required voltage swing to get the full 35W rms out of the VTA70 without an active preamp. It could be that the Kenwood is boosting the input signal more so that the overall output is louder but the peaks are clipped. SO it could appear louder but there might be distortion present. Just a guess. Are you saying that if you set the volume to full on both amps your VTA70 is still not as loud as your Kenwood?
  8. rjp

    New VTA ST-70

    Emile, Are you running an original ST70 or a modified version? Where is the attenuator you mention installed? BOTH a stepped attenuator and ANY volume pot of ANY taper will be effectively out of the circuit at full clockwise rotation (well, unless it's wired up wrong). What is you input source?
  9. rjp

    New VTA ST-70

    Emile, I think I know what you are talking about, but after reading some of the interveaning replies I am a little unsure now, so I will just speak about my experience with stepped attenuators. I had a "regular" volume pot on my VTA70 before I installed a 21 step attenuator. My first reaction was, "Why is there so much less volume now?" There is not less volume. It has just been redistributed. The difference was entirely due to the taper of the designs. The stepped attenuator (at least the most common ones) have steps that are roughly 3dB each. This means that just 2 steps down from full volume is half power. This is known as a logarithmic taper (a.k.a. Audio taper). The potentiometer I was using was a linear taper. So even though the two devices spanned a total resistance of 100K Ohms, they did so in very different ways. Most volume controls on consumer stuff are linear taper, and consequently that's what a lot of us are used to. Most audiophile stuff, however, tends to be logorithmic. WIth a linear taper control the volume initially increases quickly as you turn the knob clockwise, and then slows down. I prefer linear personally. You can get a stepped attenuator in linear as well if you like the "advantage" of discrete steps rather than continuous adjustment. Same price on ebay. Drop in replacement.
  10. Thanks for your consideration Mike, but I don't think of it as "my" thread. It is for all of us. Besides, after 11 pages I think there were only a hand full of posts actually discussing the HIII's. Which, btw, I am liking more and more lately. Ultimately, I decided to return the Monitor Audio Silver 100's and keep the HIIIs. I may put L-pads in them some day
  11. I like tone controls as much as I like L-pads. And we all know I like L-pads, right? I see no problems as long as when they are set to zero I hear absolutely no change in the signal compared to a direct path. I auditioned and ultimately returned a product called miniDSP HD for this reason. I rigged up an A/B switch on the line level inputs and with all EQ functions on the miniDSP set to off I could still hear a definite degradation in the sound quality. I assume this was due to the A/D - D/A stage itself which is essential for any digital tone control product of course. It was subtle but consistent. I performed the same test on a Schiit Loki 4 band EQ and it passed with flying colors. I may have already mentioned this above. I forget what thread I'm on sometimes. My advice is if you have to have tone controls, get the good Schiit http://www.schiit.com/products/loki Speaker placement is effective. Many people roll tubes as a method of tone control as well. All methods have one thing in common: they emphasize some frequencies more than others. It's all "tone control".
  12. I know you try to help members. Thanks for your contributions. Let's just move on for now and put this behind us.
  13. Back on Page 3 we had this conversation. I told you I like L-pads. I even told you I bought the same L-pads as you from Parts Express for just this purpose.
  14. Do they make analog versions?
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