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Old 13th May 2004, 11:34 PM   #11
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Default MR. BLUMLEIN WHERE ARE YOU NOW?

Hi,

The Decca....I had one of those rattlesnakes myself....
I can't remember what the channel separation was on those three pinners...if any.

MEMORY LANE...

Cheers,

P.S. Those Quads were the IIs, I assume? Could have kept me guessing for an integrated amp for ages....
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Old 13th May 2004, 11:45 PM   #12
SY is offline SY  United States
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No need for Quad IIs, the integrated was... integrated. ESLs, my lad, ESLs.
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Old 14th May 2004, 12:01 AM   #13
EC8010 is offline EC8010  United Kingdom
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Default Re: More envelope backs

Quote:
At the magic 100 Hz, this cap will run about 1.5 ohm in impedance (the ESRs are in the milliohm range so can be neglected).
The typical, rather nasty, capacitors that are used in an amplifier that cost-cuts in this way have significant ESR. I've just found a 100u 6V3 (which would be typical) having an ESR of 3.45 Ohm. (Rubycon MS5 series.) Assume gm of 2mA/V, giving rk of 500 Ohm, and we have crosstalk across the band at -43dB just for one stage.

By the way, FFSS (applied to Decca cartridges) stands for Fatally Flawed, Sometimes Superb. I had Deccas too... Excellent mono cartridges (if you got a good one), but stereo was a signal too far.
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Old 14th May 2004, 12:07 AM   #14
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Hi,

Quote:
No need for Quad IIs, the integrated was... integrated. ESLs, my lad, ESLs.
You sure have me puzzled there...

Quote:
FFSS
Lemme guess....Full Frequency Stereo System?
I suppose they didn't have a dictionary on stereo systems in those days either...he,he...

Quote:
but stereo was a signal too far.
Wouldn't even track a railroad....

Cheers,
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Old 14th May 2004, 12:14 AM   #15
EC8010 is offline EC8010  United Kingdom
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Not quite; Full Frequency Stereo Sound.

Deccas could track, just not vertical stuff. And they needed a really robust arm. I designed my first "proper" arm with the Decca Gold in mind. It was an oil-damped unipivot and it worked, but end-of-side distortion was still a problem, and the vibration loosened the screws securing the platter bearing on my Garrard 301. The whole thing needed to be tightened every three months!

This is wandering way off topic - it's just as well no moderators are watching.
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Old 14th May 2004, 03:20 AM   #16
jlsem is offline jlsem  United States
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Quote:
What is the disadvantages of this (crosstalk?)
What is so terrible about crosstalk? It occurs to me that it is much easier to measure than to hear.

John
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Old 14th May 2004, 04:20 AM   #17
SY is offline SY  United States
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Quote:
Originally posted by jlsem


What is so terrible about crosstalk? It occurs to me that it is much easier to measure than to hear.

John
This is true of most phenomena in audio. For ultimate performance, you want the cross-talk as low as possible. For audibly "blameless" amplification, you can tolerate quite a bit before it becomes audible.

EC: Just for grins, I measured the impedance of a 1000u/35V cap I happened to have laying around here. US$0.59 from Mouser, if memory serves. About 1 x 2 cm. Under 100 milliohms total impedance at 10kHz. Admittedly, I haven't measured it in a warmer environment yet, but...
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Old 21st May 2004, 08:48 AM   #18
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Default Re: shared parts between channels

Quote:
Originally posted by metebalci
Hi,

Is it a common practice to share components in cathode bias circuits in integrated amplifiers ? What is the disadvantages of this (crosstalk?) ? Does it have an effect on stereo seperation ? Is it another main difference between monoblock (or dual-mono) and integrated amplifiers ? (the other difference is using seperate supplies for each channel)

MB
Steve Deckert of ZEN Triode Amp fame uses one cathode resistor and bypass capacitor shared between the channels of his SE amps. I tried it when I built my psuedo-Zen and I never changed back. It improved the imaging in my system. YMMV.
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Old 21st May 2004, 04:16 PM   #19
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Hi,

Quote:
It improved the imaging in my system. YMMV.
On this preamp I have there's this funny switch labeled MONO...
I wonder what the heck it's for though???

Sorry G, this resistor couldn't...well, resist.
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