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PostPosted: Fri Aug 04, 2017 7:07 am 
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Hi,

Sounds like your restoration friend is something of a jewel. No doubt, given what you say, this is likely a superb restoration. It is, however, impossible to really know how the Paco phono stage circuit would technically compare to the Sugden, save for the fact that the Paco is a vintage tube circuit and therefore subject to the performance limitations of that era. However, many audiophiles come to like and prefer those limitations and you may too. So, just try it out.

Cheers,
David Neice

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PostPosted: Fri Aug 04, 2017 7:14 am 
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Easy to tell, borrow or buy a good external and compare.

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PostPosted: Wed Sep 27, 2017 5:45 am 
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For something of that vintage and lets say less than household name, the only way you're gonna know for sure is to try it. Back in those days there was a lot of design experimenting going on, sometimes they got things just right, sometimes, not so much.

I remember having a Dyna Pas-3 at one time. Out of the box it was good, but not spectacular. I changed a couple of things, mostly upgrading parts to better in the pre-amp and power supply sections and a new stepped attenuator and it was singing pretty good. Was thinking about upgrading the phono section, can't recall exactly who was offering it, but there was someone who had a significant upgrade design for the Pas-3 phono that got really good reviews. In the end I never did and sold it some time later.

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PostPosted: Wed Sep 27, 2017 8:51 am 
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IIRC, The PAS upgrade was a significant change to the circuit. Basically a replacement of the PCB.


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PostPosted: Thu Sep 28, 2017 4:15 am 
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Bumpy wrote:
IIRC, The PAS upgrade was a significant change to the circuit. Basically a replacement of the PCB.

I think you're right. I was about ready to do it, and for the life of me can't remember why I didn't. It was supposed to be a very good phono upgrade. If I had a litle more time, I might even try to find a PAS-3 and fiddle. Maybe a retirement project in about 15 years

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PostPosted: Thu Sep 28, 2017 7:07 am 
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If the Sugden has a tape loop, you could route the tape out, with the signal from the TT, into an aux input on the Paco to make a direct comparison of the two environments. You wouldn't necessarily have to buy a new outboard phono stage, just interconnects. You could reverse the procedure and see how the Paco's phono stage sounds, if the Paco has a tape loop as well, through the Sugden. I would want to try this just to hear how the variations compared to one another. Could be great fun. Cheers!


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PostPosted: Mon Oct 02, 2017 9:06 pm 
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The advantage of a lot of older equipment, especially those of point to point wiring vintages, is that one can easily mod and experiment with different techniques, including stage gain.
So with outside of the box thinking and a bit of patience a circuit can be tailored to correct any perceived deficiencies. (Or be totally destroyed). 8)

As an addendum to byebye88's thorough explanation of what the RIAA system does:
On cutting the master, the lows are attenuated (so the grooves variations are small enough to fit 20 to 30 minutes on a 12" disc @ 33 1/3 RPM), and the highs are boosted. The phono preamp then reverses the process to 'flatten' both ends of the spectrum (normalize); not only do the lows get boosted, but when the highs get attenuated, an inherent advantage is that a good portion of the high frequency noise of the stylus rubbing in the groove gets attenuated too.
Cool, eh?

BTW, someone earlier asked about when something became "vintage". I could never figure out how "vintage" could possibly mean "old" or "classic". It doesn't mean the same thing.
It seems more proper (and accurate) to say "I have a Fisher 500C of vintage 1964" or "My vintage 1968 HK needs repairing", or "the 1961 to 1963 vintages of HH Scott amps were the bees knees".
Nobody talks about liking vintage wine, but they do talk about wines of specific vintage or vintages. Same thing.
But I digress..........again :lol:

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PostPosted: Tue Oct 03, 2017 1:37 pm 
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cyrus wrote:
Thanks all for your valuable input and comments. The Paco in question has been completely rebuilt, phono stage included, as in all caps and resistors. The transformers are original, and are Fisher units. The amp is a thing of beauty, and even the chassis looks as close to new as you could get, with it's cosmetic restorative efforts. This guy is really amazing and literally has thousands of tubes, all laid out in specially made tube drawers floor to ceiling, along with perhaps 20-30 beautifully restored tube pieces, some that I've never seen before or knew existed (very early Pioneer tube receivers that look essentially new). The Paco has over 40 hours invested into it's restoration, and the chap is a retired electronics engineer with 45 years of rebuilding and restoring audio equipment. I suppose what it would come down to, is more circuit design for the phono stage in question, as opposed to any consideration regarding old, out of spec components. I suppose I posed the question regarding phono stage quality of the Paco, given that my Sugden A25 on board stage is so good. I'm hoping to not have to go with an outboard if I can, although I will only know upon taking it for a spin of course.


I also have a rebuilt PACO SA40 and can say they do sound nice! I'm curious though how you're able to tell they're Fisher transformers as the numbers on the end-bells don't seem to match anything by Fisher. Back then quite a number of amp builders were in NY so things may have been shared. I have a Grommes tube tuner which was also sold as the Harmon Kardon T1040. Who knows why they connected for that as Grommes was always in Illinois. Maybe to poke at that Chicago company which invented stereo FM as we know it today ... Sherwood.

-- Tue Oct 03, 2017 5:45 pm --

TwentyKHzPlus wrote:
If the Sugden has a tape loop, you could route the tape out, with the signal from the TT, into an aux input on the Paco to make a direct comparison of the two environments. You wouldn't necessarily have to buy a new outboard phono stage, just interconnects. You could reverse the procedure and see how the Paco's phono stage sounds, if the Paco has a tape loop as well, through the Sugden. I would want to try this just to hear how the variations compared to one another. Could be great fun. Cheers!


Yes, the PACO has a Tape Out.

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