They're passed through different sections in the same envelope. This compromises separation at megahertz frequencies, which is not terribly worrisome. At audio frequencies, the weakest link is usually the volume control or the selector switch.
To put things into perspective, a good phono cartridge might have 20dB of separation. A preamp will be 100-10,000 times better than that.
To put things into perspective, a good phono cartridge might have 20dB of separation. A preamp will be 100-10,000 times better than that.
I've been reading through this thread but just ran out of time at work, so apologies if this has already been answered.
The original Impasse specified a 650 VCT 40mA 6.3 VCT 2A mains transformer.
What are the upper and lower limits of these supplies. I expect the 6.3V to be about 2A but can the HT be say 620V or 640V as the American transformers are expensive here in the UK.
The original Impasse specified a 650 VCT 40mA 6.3 VCT 2A mains transformer.
What are the upper and lower limits of these supplies. I expect the 6.3V to be about 2A but can the HT be say 620V or 640V as the American transformers are expensive here in the UK.
Yes, the regulator will take up that slack. If the raw DC is too low for the regulator to cope with, you can set the regulator output a bit lower without much issue.
SY, as the Impasse is now a few years old, were there any significant improvements to the original design ?
Personally, I would like to build the Impasse without the input transformers. My source is very close the pre-amp so input leads are not a problem.
They can always be added later but at $60 each here in the UK, and an added source of "loss of fidelity", I'll try it without them first.
They can always be added later but at $60 each here in the UK, and an added source of "loss of fidelity", I'll try it without them first.
To tell you the truth, I don't use one- I only need unity gain in my system. So no, haven't changed anything and there's not much in there to change.
Input transformers are seen as a trade-off, and with good grounding and layout all up and down your signal chain, you can probably achieve low noise without them. Probably. With a transformer, certainly, but that costs something, as you correctly observe. I don't think there's a fidelity loss with good input transformers, and in some cases there's a measurable (and sometimes audible) difference for the better.
Input transformers are seen as a trade-off, and with good grounding and layout all up and down your signal chain, you can probably achieve low noise without them. Probably. With a transformer, certainly, but that costs something, as you correctly observe. I don't think there's a fidelity loss with good input transformers, and in some cases there's a measurable (and sometimes audible) difference for the better.
I'm currently using the B1 with an Aleph4 but I feel that there isn't quite enough gain in the system.
Certainly at 100% it's not as loud as I would expect 100W to be.
I can use almost 100% on the B1 volume control for comfortably LOUD listening. I would expect 100W to be almost uncomfortable.
My speakers are B&W DM683's which are not the most sensitive speakers in the World.
Certainly at 100% it's not as loud as I would expect 100W to be.
I can use almost 100% on the B1 volume control for comfortably LOUD listening. I would expect 100W to be almost uncomfortable.
My speakers are B&W DM683's which are not the most sensitive speakers in the World.
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The ImPasse will certainly have enough gain!
The issue is that you are nowhere near 100W if you are maxing out your B1. As you know, it has just a teensy bit less than unity gain, so the output of whatever source you are listening to is all you get.
Plus, the Alephs only have about 20db of gain, so having a bit more oomph in the preamp will be quite helpful. The ImPasse will have plenty.
The issue is that you are nowhere near 100W if you are maxing out your B1. As you know, it has just a teensy bit less than unity gain, so the output of whatever source you are listening to is all you get.
Plus, the Alephs only have about 20db of gain, so having a bit more oomph in the preamp will be quite helpful. The ImPasse will have plenty.
I've just ordered the Allied 6K3VG from the US so I'm now on the building trail.
My main source is an Arcam CD36 which I believe chucks out about 2V RMS
My main source is an Arcam CD36 which I believe chucks out about 2V RMS
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Has the schematic become "common domain" yet, I downloaded it. It would be nice to put it in here for comments.
It's not, but you have my permission to post it here. A pdf of the original article (with schematics) is on my website.
It's amazing, the Allied 6K3VG is only $29 from the US plus possibly GUESSING HERE $50 postage. Why is the same transformer £250 here ?
Why are R3 and R10, the grid stoppers, specified as Carbon Composition?
I have ordered both carbon film and carbon, which should I use ?
I have ordered both carbon film and carbon, which should I use ?