Catman's Analog Musings

[Saxon Hall]

OK I will bite.

I prefer the sound of a CD over the sound of a record.

I could post up all my reasons and justifications but as I am just expressing my opinion, there is no need.

I just prefer a CD.

[stevoz]

@Saxon Hall .....and in true Christmas spirit, I won't bite back. Seriously though, it's all subjective and our own ears are our ultimate guide, I'm just happy everyone can enjoy music the way they like it best.

[catman]

Sometimes I really hate this hobby.

 

G'day all, and not just records either, but the whole hi fi audio world as well.  It is just that sometimes things 'do' sound subtly different but that is no real reason to either like of hate any particular bit of gear.  Just different, if that makes any sense. 

 

I guess that there is some gear that I don't like at all for whatever reason, but that situation is thankfully rare!  Phono stages for example, my Schiit 'Mani' is fabulous and it certainly has a unique sound as such, but listening to my DIY ESP P06 tonight it is also excellent and if anything its 'hiss' level is actually slightly less than the 'Mani'.  Again in the sonic sense, just subtly 'different'.  Sometimes!  Regards, Felix. 

[naggots]

1 hour ago, catman said:

Sometimes I really hate this hobby.

 

G'day all, and not just records either, but the whole hi fi audio world as well.  It is just that sometimes things 'do' sound subtly different but that is no real reason to either like of hate any particular bit of gear.  Just different, if that makes any sense. 

 

I guess that there is some gear that I don't like at all for whatever reason, but that situation is thankfully rare!  Phono stages for example, my Schiit 'Mani' is fabulous and it certainly has a unique sound as such, but listening to my DIY ESP P06 tonight it is also excellent and if anything its 'hiss' level is actually slightly less than the 'Mani'.  Again in the sonic sense, just subtly 'different'.  Sometimes!  Regards, Felix. 

How does the Lounge LCRmk3 sound in comparison?

[catman]

G'day mate, the Lounge LCR MK 3 is a bit of an acquired taste in all honesty.  It is extremely well engineered and build quality and is low noise and has great bass and is good throughout the audio spectrum, yet is some respects it is not my favourite phono stage.  Is it worth the asking price?  If you like its 'sound', yes, but if not ....  It's very much a question of individual taste!  Is the LCR approach inherently superior?  In my heartfelt opinion, no.  Regards, Felix.   

Edited December 27, 2017 by catman
Spelling.

[andyr]

29 minutes ago, catman said:

G'day mate, the Lounge LCR MK 3 is a bit of an acquired taste in all honesty.  It is extremely well engineered and build quality and is low noise and has great bass and is good throughout the audio spectrum, yet is some respects it is not my favourite phono stage.  Is it worth the asking price?  If you like its 'sound', yes, but if not ....  It's very much a question of individual taste!  Is the LCR approach inherently superior?  In my heartfelt opinion, no.  Regards, Felix.   

 

Hi Felix,

 

I've only ever listened to one LCR phono stage - so don't have as good a handle on the particulars of LCR sound as you do ... but would you say the Lounge is a bit 'polite' ('laid back') in nature, compared to, say, your Elliott?

 

Andy

 

[catman]

G'day mate, I don't really know if the Lounge is representative of LCR designs as it is uniquely implemented in the Lounge design!  Polite?  No.  Slightly biased towards the bass?  Possibly, and likewise not particularly 'fast sounding'. 

 

Also is anyone having any difficulties accessing this forum?  I certainly have at various times in recent days.  Regards, Felix.   

[naggots]

2 hours ago, catman said:

G'day mate, I don't really know if the Lounge is representative of LCR designs as it is uniquely implemented in the Lounge design!  Polite?  No.  Slightly biased towards the bass?  Possibly, and likewise not particularly 'fast sounding'. 

 

Also is anyone having any difficulties accessing this forum?  I certainly have at various times in recent days.  Regards, Felix.   

Thanks Felix, Have you compared the lounge to Graham slee?

[catman]

G'day mate, no I haven't, however although the Slee designs are sometimes a little unconventional, they are similar to typical full feedback op amp designs in most cases, and as such they can sound pretty good.   

 

One point that I haven't yet raised is one of distortion.  The Lounge does have measurably higher distortion than most op amp full feedback designs, and although the Lounge LCR distortion is low and reputed to be mostly second and fourth harmonic to my ears, there is a certain lack of clarity apparent.  Regards, Felix. 

[catman]

One or two db!

 

G'day all, ah the subject of decibels or 'db's'.  Going back to my telecommunication technician days the term decibels or db's is fundamentally important, not as a 'unit' per se, but a level reference, however I will admit that even today I do find the terms slightly confusing as sometimes 'one or two db' difference in level can be quite audible and significant. 

 

Listening to my Cambridge CP1 tonight, it's official gain of 39 db, slightly less than my general phono stage reference of '40 db' is actually quite noticeable when setting my line preamp levels!  I have some phono stages (DIY and commercially made) of considerably less than 40 db gain and  they sound to me overly quiet and lacking audio drive! 

 

I wish that the CP1 was 40 db and not 39 db, but as it is a very nice sounding phono preamp, I can accept the 1 db difference, (but only just).  Being a logarithmic scale, the level difference compared to a linear scale is sometimes hard to fathom.  However 'decibels' are part of the electronic language for better or worse!  https://en.wikipedia.org/wiki/Decibel   Fun!  Regards, Felix.        

Edited January 1, 2018 by catman
Spelling.

[catman]

Trying to explain 'break in'.

 

G'day all, this is a subject that I constantly debate, even whether it is real or not!  Well let me say this, I think 'some' kinds of break in are real and quite noticeable like aspects of mechanical break in.  I have seen (and heard) this sort of thing many times over the years.  What about 'other' kinds of break in, like for example electronic component break in?  Well this is where I think that it gets exceedingly murky, and examples of simply 'getting used to a given sound' is much more likely! 

 

Yet maybe not always!  If there is one component that 'might' change is a discernable way, it is the humble electrolytic capacitor.  They are interesting things, and at least one respected authority not prone to this kind of 'subjective nonsense', actually thinks that electrolytic capacitor behaviour change could very well be real.

 

My own experience has a bit of both!  Over the years I have used/built/bought audio gear that simply didn't change performance/sound in any noticeable way except maybe through a fault condition.  Having said that though there have been one or two examples that did, and in those cases there was 'always' a reasonably large electrolytic capacitor in the signal path, so what am I to think?  Possibly! 

 

What about so called 'professional' audio gear?  In this area, gear just simply has to work properly and be ultra reliable.  That is the ultimately important thing!  I saw many examples of this in my telecommunications technician work days, and to be honest I can't say that I ever noticed anything remotely similar to 'break in'.  So again, quoting a song lyric, 'what is real and what's for sale'.  I don't really know....maybe.  Regards, Felix.   

[andyr]

3 minutes ago, catman said:

Having said that though there have been one or two examples that did, and in those cases there was 'always' a reasonably large electrolytic capacitor in the signal path, so what am I to think?  Possibly! 

 

 

Electrolytic caps don't belong in the signal path IMO, Felix.  I never use them.

 

Even so, with film caps ... I believe 'break-in' is real.

 

Andy

 

[catman]

G'day mate, sometimes given the circuit an electrolytic capacitor in the signal path is sometimes 'unfortunately' necessary!  Regards, Felix.   

[andyr]

2 minutes ago, catman said:

G'day mate, sometimes given the circuit an electrolytic capacitor in the signal path is sometimes 'unfortunately' necessary!  Regards, Felix.   

 

Why do you say it is 'necessary', Felix?

 

IME, coupling caps are generally 1uF - sometimes 2.2uF ... and occasionally 4.7uF.  Film caps are easily available in these values - whether you want to use Wima, MultiCaps ... or Jupiter Copper Foil, Paper & Wax!

 

Andy

 

[catman]

G'day mate, DC offsets in low impedance circuits for  example  Regards, Felix.  

 

[andyr]

4 minutes ago, catman said:

G'day mate, DC offsets in low impedance circuits for  example  Regards, Felix.  

 

Sorry, you've lost me, Felix. 

 

How large a cap value do you need, IYO?

 

AIUI - and as I'm sure you know - yes, a series cap is used on the output of a preamp, say, to stop DC offset passing into the power amp.  But this series cap has a shunt resistor at its output end; the pair act as a LP filter ... the approximate value of the roll-off point is - again, as I'm sure you know - given by the equation:

• frequ = 160,000 / (R * C in uF)

So a 1uF cap  with, say, a 221K res gives a roll-off point of <1Hz ... which is more than adequate. 

 

Andy

 

[almikel]

1 hour ago, andyr said:

Sorry, you've lost me, Felix. 

 

How large a cap value do you need, IYO?

 

AIUI - and as I'm sure you know - yes, a series cap is used on the output of a preamp, say, to stop DC offset passing into the power amp.  But this series cap has a shunt resistor at its output end; the pair act as a LP filter ... the approximate value of the roll-off point is - again, as I'm sure you know - given by the equation:

• frequ = 160,000 / (R * C in uF)

So a 1uF cap  with, say, a 221K res gives a roll-off point of <1Hz ... which is more than adequate. 

 

Andy

 

I have to agree with Andy, although high resistor values do create "thermal noise", so let's reduce the shunt resistor to 10K and the 3dB point is still only 15.9Hz. Bump up the cap to 2.2uF (still easily achievable without electros) with a 10K shunt and you get a 7Hz 3dB point - still works fine.

Electro caps are great in power supplies - I see no requirement for them in any signal path.

 

In my previous speakers I used 56uF MKT caps in series with my tweeters for protection in an active setup - they were big and much more expensive than bipolar electros, but in a DIY context why would you use electros anywhere other than the power supply?

 

cheers

Mike

[andyr]

8 hours ago, almikel said:

I have to agree with Andy, although high resistor values do create "thermal noise", so let's reduce the shunt resistor to 10K and the 3dB point is still only 15.9Hz. Bump up the cap to 2.2uF (still easily achievable without electros) with a 10K shunt and you get a 7Hz 3dB point - still works fine.

Electro caps are great in power supplies - I see no requirement for them in any signal path.

 

In my previous speakers I used 56uF MKT caps in series with my tweeters for protection in an active setup - they were big and much more expensive than bipolar electros, but in a DIY context why would you use electros anywhere other than the power supply?

 

cheers

Mike

 

Not sure I can agree with you, Mike:

1. Shirley, thermal noise is important in a series res - but not a shunt res?
2. The Zin of the following component could well be 47K.  If you have a shunt res of 221K in the first component ... then it combines with the 47K to produce a Zin of almost 39K ohms - which is perfectly acceptable.  But if you have a shunt res of only 10K on the first component - then you get an effective Zin of just over 8K - which I suggest is not OK!

Andy

 

[aussievintage]

1 hour ago, andyr said:

 

1. Shirley, thermal noise is important in a series res - but not a shunt res?

 

 

 

It's a problem with the shunt resistor too.  Noise generated by the resistor due to temperature is effectively applied direct to the input of the next stage.  What saves it somewhat, is that it is not subjected to the gain of the previous stage, so with less gain, less problems.

[aussievintage]

10 hours ago, almikel said:

Electro caps are great in power supplies - I see no requirement for them in any signal path.

 

Power supply filter caps are in the signal path.  Bypassing them with smaller better quality caps will help the situation.

[almikel]

On 1/9/2018 at 7:53 AM, andyr said:

 

1. The Zin of the following component could well be 47K.  If you have a shunt res of 221K in the first component ... then it combines with the 47K to produce a Zin of almost 39K ohms - which is perfectly acceptable.  But if you have a shunt res of only 10K on the first component - then you get an effective Zin of just over 8K - which I suggest is not OK!

Andy

 

you're correct of course - brain fade on my part given we were specifically referring to de-coupling caps

On 1/9/2018 at 7:53 AM, andyr said:

1. Shirley, thermal noise is important in a series res - but not a shunt res?

back at uni (geez > 30years ago now) if we were designing circuits for lowest noise a "rule of thumb" was to try and keep resistors (shunt or series) below 100K - not always possible of course, but if building say an op amp filter you can obviously juggle the other component values to keep resistors low enough to keep thermal noise down, but high enough depending on location not to drag too much current from the op amps. As always, compromise was often required.

 

On 1/9/2018 at 9:25 AM, aussievintage said:

Power supply filter caps are in the signal path.  Bypassing them with smaller better quality caps will help the situation.

Agreed this is definitely necessary for op amps and chip amps to maintain a low impedance for the DC supply. These bypass caps need to be as close to the device as possible given the speed of modern op amps often have a bandwidth into MHz and long leads or pcb tracks can have enough inductance to make the device oscillate.

 

cheers

Mike

[catman]

G'day all, yes it's all part of the fun that comes with analog circuit design.  Bypass caps on high speed op amps are practically mandatory, generally 10 uf in parallel with .1 uf (ceramic), but more often than not, they are made necessary by 'compromises' in power supply arrangements (speaking from personal experience). 

 

I recall building a simple op amp project that screamed with oscillation until I remembered omitting any bypass capacitors.  As it turned out only .1 uf monolithic ceramic capacitors were necessary!  With the bypass capacitors in place all oscillation simply disappeared.  It was remarkable to observe the difference!  I prefer not to use electrolytic capacitors in coupling applications but I have seen well regarded audio projects that have done so with absolutely no ill effects, 'when properly used'.  Regards, Felix.     

Edited January 10, 2018 by catman
Addition.

[andyr]

40 minutes ago, catman said:

I recall building a simple op amp project that screamed with oscillation until I remembered omitting any bypass capacitors.  As it turned out only .1 uf monolithic ceramic capacitors were necessary!  With the bypass capacitors in place all oscillation simply disappeared.

 

You said these were 'bypass capacitors' ... so I'm assuming not series caps in the signal path?

 

40 minutes ago, catman said:

I prefer not to use electrolytic capacitors in coupling applications but I have seen well regarded audio projects that have done so with absolutely no ill effects, 'when properly used'.  Regards, Felix.     

 

Shirley, by "properly used" ... you mean they didn't sound bad!!??  That's not the issue - the 'issue' is ... would the sound have been better if they had used film coupling caps instead of electros! 

 

Andy

 

[almikel]

10 minutes ago, catman said:

Bypass caps on high speed op amps are practically mandatory 

agreed

11 minutes ago, catman said:

 but more often than not, they are made necessary by 'compromises' in power supply arrangements 

if you regard bypass caps as part of the power supply (I do), then bypass caps just become part of good power supply design when working with high speed op amps. As you know, their purpose is to provide a low impedance DC supply as close to the device as possible given the bandwidth of the device...

...so not so much made necessary by compromises in power supply arrangements, but just necessary for good power supply arrangements.

 

21 minutes ago, catman said:

 I prefer not to use electrolytic capacitors in coupling applications but I have seen well regarded audio projects that have done so with absolutely no ill effects, 'when properly used'.  Regards, Felix.     

I have also, and in a DBT, likely you'd never hear a difference, but in DIY, it's easy not to use electros for coupling, so I don't - quite possibly only because I've drunk at the CoolAid/SnakeOil fountain where all electros in the signal path are regarded as bad...

...Even though many high(ish) end speakers use Bipolar Electros in their passive Xovers - IMHO this would cause much greater distortion issues than an electro cap preventing DC to pass between components...

...and in passive crossovers, inductors are a bigger issue than the caps, plus the changing impedance of the drivers etc etc...different discussion

 

cheers

Mike

[catman]

G'day all, there are a couple of electrolytic coupling capacitors in this design but as explained in the article they cause no problems, and having built this phono stage myself, it is excellent! https://www.akitika.com/PhonoPreamp.html  Regards, Felix.