Catman's Analog Musings

[Warren Jones]

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So true and to expand, circuit topology and PSRR are important ie how immune is the device to noise.

 

If the unit has NFB how has it been implemented. NFB can reduce distortion artifacts, but if implemented incorrectly can also introduce phase anomalies, ie the group delay varies with frequency causing the higher order harmonics to be offset in the time domain from the fundamental note.

 

 

[catman]

Serendipity?

 

I recently posted how my original Schiit Mani mysteriously failed for no apparent reason but I had the good sense to buy a Mani 2 recently.  I used it for a while today and it is really excellent, and I don't miss the original Mani at all!  Swings and roundabouts a plenty!  Regards, Felix. 

 

[catman]

Do you have a favourite (favourite) phono stage?

 

G'day all, this is (for me anyway) difficult to answer I have so many generally excellent phono stages, but in terms of sheer musical enjoyment, I might have to give it to my Rothwell 'Simplex'.  There is just 'something' about its sound!  Regards. Felix.     

[Monkeyboi]

5 hours ago, catman said:

Do you have a favourite (favourite) phono stage?

 

G'day all, this is (for me anyway) difficult to answer I have so many generally excellent phono stages, but in terms of sheer musical enjoyment, I might have to give it to my Rothwell 'Simplex'.  There is just 'something' about its sound!  Regards. Felix.     

 

My favourite phono stage was in a Sony TA-E77ESD preamplifier.  I now regret selling it.  

[catman]

Break in revisited.

 

G'day all, this is admittedly a subject that I've never been too sure about and maybe I have to admit that break in is potentially real and can take literally a long time, even years! 

 

Re-reading my old posts posts on the NAD PP2e, it is apparent that its sound has changed for the better, and gone from mellow and warm, to coolish and crisp and even musical.  I know that the NAD PP2e has a number of electrolytic capacitors in the 'signal path', and failing any other plausible technical explanation I have to account these these sonic changes to electrolytic capacitor behavior.  For what it's worth, although not a perfect phono stage, its unique sound is quite appealing.  Regards, Felix.  

Edited June 6, 2022 by catman
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[andyr]

27 minutes ago, catman said:

Break in revisited.

 

G'day all, this is admittedly a subject that I've never been too sure about and maybe I have to admit that break in is potentially real and can take literally a long time, even years! 

 

Re-reading my old posts posts on the NAD PP2e, it is apparent that its sound has changed for the better, and gone from mellow and warm, to coolish and crisp and even musical.  I know that the NAD PP2e has a number of electrolytic capacitors in the 'signal path', and failing any other plausible technical explanation I have to account these these sonic changes to electrolytic capacitor behavior.  For what it's worth, although not a perfect phono stage, its unique sound is quite appealing.  Regards, Felix.  

 

I would suggest you are absolutely spot on about the change in your PP2e's sound being due to electros 'breaking in', Felix.  

 

But my view is ... electrolytic caps don't belong in the signal path - only on power rails.  I certainly don't use them in the signal path of anything I build.  

 

Andy

 

[catman]

G'day mate, a good point but actually using electro's might be considered an 'easy way out'.  Certainly with the simple preamp stuff that I've built, using electro's have certainly sorted out some interesting design issues.  Oh well, I'll use them when I have to, but only then!  Regards, Felix.  

[andyr]

3 hours ago, catman said:

Certainly with the simple preamp stuff that I've built, using electro's have certainly sorted out some interesting design issues.  Oh well, I'll use them when I have to, but only then!  Regards, Felix.  

 

Mmmm, sorry, Felix ... "using electros has certainly sorted out some interesting design issues"??  I cannot understand how (compared to using film caps) - care to elaborate?

 

Andy

 

[Warren Jones]

There is a lot of gear that use EC's in the signal path. MiniDSP for one use EC's as AC coupling caps on all of the analog I/O. I have bypassed them in my MiniDSP as the caps have no DC bias.

 

This is a screen shot of a paper by Texas instruments. The paper performed some quantitative analysis of various caps in the signal path. SNA won't let me attach the PDF.

 

 

 

[MLXXX]

3 hours ago, Warren Jones said:

This is a screen shot of a paper by Texas instruments. The paper performed some quantitative analysis of various caps in the signal path. SNA won't let me attach the PDF.

 

The graph appears on page 3 of the Texas Instruments paper, "Selecting capacitors to minimize distortion in audio applications".  For anyone wanting to peruse the pdf, here is a link to it: https://www.ti.com/lit/an/slyt796/slyt796.pdf?ts=1654545668602

[catman]

G'day all, many thanks for the interesting comments.  I do wonder why I have noticed these sonic changes after such a long period of time? 

 

Andyr:  With the generally low impedance circuitry that I mainly use, electrolytic capacitors are often the only option for the larger capacitance values needed.  Regards, Felix.  

[andyr]

42 minutes ago, catman said:

Andyr:  With the generally low impedance circuitry that I mainly use, electrolytic capacitors are often the only option for the larger capacitance values needed.  Regards, Felix.  

 

Aaah, OK.  

 

So you use larger than, say, 2.2uF then, Felix?

 

Andy

 

Edited June 7, 2022 by andyr

[catman]

G'day mate, yes 100 uf is an often used value in some of my circuits for example.  Regards, Felix.   

Edited June 7, 2022 by catman
Grammar.

[andyr]

1 hour ago, catman said:

G'day mate, yes 100 uf is an often used value in some of my circuits for example.  Regards, Felix.   

 

Aah, OK - yes, then you don't have much choice!  

 

But 100uF for a coupling cap (directly in the signal path) - wow!  

 

Andy

 

[catman]

Can you keep on improving audio gear?

 

G'day all, Listening to my Schiit Mani 2 today I find myself asking if one can keep on improving any piece of audio gear?  The original Mani was pretty good,  but the Mani 2 is actually audibly a lot better.  From what I've read the circuit changes are considerable, and I wonder if further improvements are possible?  Mmmmm.  Regards, Felix.  

 

[andyr]

45 minutes ago, catman said:

Can you keep on improving audio gear?

 

G'day all, Listening to my Schiit Mani 2 today I find myself asking if one can keep on improving any piece of audio gear?  The original Mani was pretty good,  but the Mani 2 is actually audibly a lot better.  From what I've read the circuit changes are considerable, and I wonder if further improvements are possible?  Mmmmm.  Regards, Felix.  

 

Can the cct be improved - undoubtedly!  But you'll have to wait for Schiit to do it.  

 

Can the sound of the existing version be made better - again, undoubtedly.    Use boutique caps in coupling and RIAA positions - and better 'lytics on the power rail(s).  Of course ... it might be a problem to fit them onto the PCB!  

 

Andy

 

Edited June 11, 2022 by andyr

[catman]

Sony PS X55 turntable.

 

G'day all, I was recently 'given' (yes) an old Sony PS X55 turntable that lights up a red power on LED when powered on, but does nothing else.  It is a beautiful looking turntable, but getting it going may be beyond me.  Does anybody have any comments and/or suggestions for possible repair?  Regards, Felix.   

Edited June 12, 2022 by catman
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[muon*]

It's  fully auto direct drive so a few electrolytic caps in there that may be past there use by date, and the controls likely might need cleaning. As long as the integrated circuits are OK you have a good chance of getting it working again.

 

service manual on VE

https://www.vinylengine.com/library/sony/ps-x55.shtml

[catman]

'Little' things in phono preamp sound quality.

 

G'day all, this has been a long time interest of mine and I have mused about it often and even to the point of wondering if I am just kidding myself using terms such as 'musicality'! 

 

I honestly believe this and some of my phono stages definitely have that 'sound' about them and although pretty well most of my phono stages sound pretty good a few of them just sound, dare I say......musical.  Do records have this inherent quality when originally pressed, or is the just a preamp thing?  I don't know! 

 

My Rothwell Simplex has this sound quality in spades but strangely enough my NAD PP2e has more than a hint of it!  I really wish that I could fully articulate this.  Valve (tube) aficionados often use the same wording to describe sound quality!  Isn't this fun?  Regards, Felix.  

[catman]

Phono stages and stereo imaging. 

 

Ordinarily one would think that phono cartridges would be the limiting factor and with possibly good reason, yet at least one of my own phono stages, when playing certain test records, that seem to exhibit slightly narrowed stereo imaging. 

 

I guess that it is an interesting question, all things being equal!  Maybe it comes down to component matching between the two stereo channels, as I have always tried to optimise this aspect with my own DIY creations and I believe that it does make an audio difference.  I'm not going to going to say which of my phono stages has this narrowed stereo image issue, but it is a highly regarded but inexpensive, commercially made unit.  Interesting stuff!  Regards, Felix.   

Edited June 23, 2022 by catman
Grammar.

[andyr]

57 minutes ago, catman said:

Phono stages and stereo imaging. 

 

Ordinarily one would think that phono cartridges would be the limiting factor and with possibly good reason, yet at least one of my own phono stages, when playing certain test records, that seem to exhibit slightly narrowed stereo imaging. 

 

I guess that it is an interesting question, all things being equal!  Maybe it comes down to component matching between the two stereo channels, as I have always tried to optimise this aspect with my own DIY creations and I believe that it does make an audio difference.

 

Yes, I think you have hit the nail on the head, Felix.    In DIY, one tends to do this ... commercial units, not so much.  

 

57 minutes ago, catman said:

I'm not going to going to say which of my phono stages has this narrowed stereo image issue, but it is a highly regarded but inexpensive, commercially made unit.

 

C'mon - don't wimp out!    You're simply giving your personal PoV - not slagging off about a particular piece of kit.

 

Andy

 

[catman]

NAD gear.

 

G'day all, for many years during my early years in Hi Fi and records in the 1980's, most of my gear at the time was NAD and it was pretty good.  In latter years my attitude to NAD changed, especially after op amps became a major part of their circuitry, including phono stages, yet more recently I seem to have found a new respect and admiration for NAD gear, and looking around the internet NAD  seem to be bringing out some pretty high performance and innovative gear and even my humble NAD PP2e phono stage is rapidly becoming a personal favourite despite being shall we say, somewhat 'quirky' in some respects, it is a very nice phono stage to listen to in most respects.  Interesting!  Regards, Felix.  

Edited June 24, 2022 by catman

[surprisetech]

On 24/06/2022 at 11:28 AM, catman said:

NAD gear.

 

G'day all, for many years during my early years in Hi Fi and records in the 1980's, most of my gear at the time was NAD and it was pretty good.  In latter years my attitude to NAD changed, especially after op amps became a major part of their circuitry, including phono stages, yet more recently I seem to have found a new respect and admiration for NAD gear, and looking around the internet NAD  seem to be bringing out some pretty high performance and innovative gear and even my humble NAD PP2e phono stage is rapidly becoming a personal favourite despite being shall we say, somewhat 'quirky' in some respects, it is a very nice phono stage to listen to in most respects.  Interesting!  Regards, Felix.  

 

Hi Felix, I'd agree with you on that.

Do you recall the models that you owned in the 80's?

 

I never owned any NAD gear until purchasing a couple of vintage items over the last 10 years or so, and both of those had stood the test of time.  First was a Model 613 Cassette Deck that only needed a new belt and the 2nd a Model 412 AM/FM Tuner that just needed new lamps behind the display.   The Cassette deck was moved on to another SNA member who was also very impressed with it, but I still have the Tuner.

 

I did have NAD products on my short lists for various purchases over the years, but the pricing I was getting on Marantz gear through the Philips staff shop always tipped the balance and I was also a fan of Yamaha products for their great value.

 

I always had the impression that equal engineering effort was put into all NAD products.  While they weren't always the best at their price point, they were always up there and consistent across the entire product range.  If you preferred all the electronics in your hifi system to be one brand, at their price point, NAD was one of only a handful of brands you could happily do that with.

[catman]

G'day mate, from memory they were a 5420 CD player (still working), a 3155 integrated  amplifier (still have it but it has a fault and is no longer working, a 4125 AM/FM tuner (still working perfectly) and a NAD cassette deck that is missing somewhere.  Regards, Felix.    

 

[catman]

Belt drive 'belt' issues!

 

G'day all, after tolerating an obviously stretched drive belt on my Marantz TT, I ordered a couple of new and spare belts of the correct size one of which is now installed and working fine. 

 

A couple of questions please.  How long should a belt last before needing replacement?  Additionally it is obvious  that the speed is now noticeably faster, and closer to 33 1/3 RPM.  Any comments please?  Regards. Felix.  

Edited June 28, 2022 by catman
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