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113 Search Results Found |
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Forum: Source «»
Posted on: Mon, 23 January 2023 20:17 «»
By: gofar99
Re: Practical limit to tube based phono preamps
Hi, Good stuff. I nearly always use JJ small signal tubes. As you noted they are quiet and accurate. I like simple designs with as few stages as necessary with as few components as needed to do the job. It is possible to achieve really excellent resul...
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Forum: Source «»
Posted on: Sun, 15 January 2023 22:13 «»
By: positron
Re: Practical limit to tube based phono preamps
So true. I personally designed at least 4 stages of filtering in my amps pre output stage, and I went from 5 to 6 stages of power supply filtering for my preamplifier. I use 2 chassis design, and 6 stages of filtering in my phono stage as well.
Cheers...
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Forum: Source «»
Posted on: Fri, 13 January 2023 17:18 «»
By: Wayne Parham
Re: Practical limit to tube based phono preamps
I'm with you there. The most annoying noise to me - by far - is power supply hum. If a tube amp keeps that down below audibility, it's a big deal to me. That's so rare. This is especially true when you stack all tube phono stage, preamp and power amp...
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Forum: Source «»
Posted on: Wed, 11 January 2023 17:47 «»
By: positron
Re: Practical limit to tube based phono preamps
A few thoughts for the newbies out there.
1. Tubes produces internal noise from a variety of reasons.
2. The resistors associated with said tube also produce noise.
A. The cathode resistor noise will be amplified by the tube's gain.
...
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Forum: Source «»
Posted on: Thu, 27 January 2022 17:32 «»
By: positron
Re: Wide Spread RIAA Phono Stage Inaccuracies by Manufacturers
If I may Gofar, I think I can help with a closer, more accurate, and long term stability/success. I agree, no negative feeback loops, except for a very small amount of current feedback from the cathode resistor to give biasing etc (in my design). You may w...
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Forum: Source «»
Posted on: Tue, 25 January 2022 20:44 «»
By: gofar99
Re: Wide Spread RIAA Phono Stage Inaccuracies by Manufacturers
Hi Good thoughts, but my experience is somewhat different. I find that tubes from one company do not always match characteristics with those from another. Several parameters can differ, Mu, Rp, residual noise and MillerC. Rp is the thing that seems mos...
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Forum: Source «»
Posted on: Mon, 24 January 2022 09:36 «»
By: positron
Re: Wide Spread RIAA Phono Stage Inaccuracies by Manufacturers
If I understand you correctly, the actual accuracy of the rest of the system also needs to be investigated. With that in mind, I don't seen any reason not to start with the RIAA network as it costs very little.
I have tried different tubes and the ...
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Forum: Source «»
Posted on: Sun, 23 January 2022 20:21 «»
By: gofar99
Re: Wide Spread RIAA Phono Stage Inaccuracies by Manufacturers
Hi, I have found the various sets of formulas to be more or less close. They don't tell the whole story as the compliance with RIAA requires the output of the preamp to be right, not necessarily any individual stage. I use a 1% accurate inverse network w...
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Forum: Source «»
Posted on: Sun, 23 January 2022 14:36 «»
By: Strum Drum
Re: Wide Spread RIAA Phono Stage Inaccuracies by Manufacturers
Thank you, positron, for explaining the situation in simple terms. You would make a great teacher. I'm just so surprised that they messed up the math. It does seem complicated, though. Well, honestly, it goes over my head. Thanks for the share. It wa...
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Forum: Source «»
Posted on: Sat, 22 January 2022 23:27 «»
By: positron
Re: Wide Spread RIAA Phono Stage Inaccuracies by Manufacturers
What Stanley is stating is that the design equations used by the designers/engineers are not correct. It is one thing to calculate a single pole complex math problem, but when multiple poles are needed, very complex math is needed. The designers/engineer...
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