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Catman's Analog Musings

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I can't see me going anywhere other than my Tron phono stage for now. It is the most expensive piece of audio equipment i have purchased to date. It is tube based so there will be more rolling to come to dial in the flavour i like.
Before this i had the Jasmine 2 box phono but this was bettered by the phono stage in my ME pre so i moved it on. If i want a more clear and dynamic sound i sometimes give the ME a run but still find myself coming back to the Tron for a more effortless sound.
My next stop will be trying to sort out the capacitance as I'd like to have a play there. Is there a way of measuring what a Stanton 881s needs in this area? Is there a box i could use in between the TT's output rca's and the Tron phono where i could dial this in?
Maybe this could be your next diy build@catman

P.s. i like your polite musings mate.

Sent from my SM-G930F using Tapatalk

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Guest Misterioso
1 hour ago, TOPSHELF said:

I can't see me going anywhere other than my Tron phono stage for now. 

+1

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1 hour ago, TOPSHELF said:


My next stop will be trying to sort out the capacitance as I'd like to have a play there. Is there a way of measuring what a Stanton 881s needs in this area? Is there a box i could use in between the TT's output rca's and the Tron phono where i could dial this in?
Maybe this could be your next diy build@catman

P.s. i like your polite musings mate.
 

 

Topshelf, if you read the spec sheet for Stantons (available on the web), I think you will find that 275pF load is the recommendation.  This is the final value that the cart needs to see - so it is, of course, the sum of:

  1. the default cap loading on your Tron (does it have any options?)
  2. the capacitance of your headshell and arm wiring, and
  3. the capacitance of the phono cable back to your Tron.

If the 3 capacitances above don't add up to 275pF ... you need to use an added load plug.  Which you can do with an RCA 'T' connector, if the Tron doesn't offer cap options or parallel input RCAs.

 

In my situation:

  • the default loading of my Muse phono stage is 110pF
  • I estimate the capacitance of my headshell and arm wiring is 20pF
  • but the capacitance of my phono cable is 50pF.

This adds up to 180pF - so I need to use a 90 or 100pF load plug to set up my Stanton 'WOS CS100' optimally.

 

 

Andy

 

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Hi Andy, thanks the Tron has no loading options and may have been set up specifically for the previous customers cart. I'd say this information would be available. The wires on the classic are like hairs so i will try to find a value for them too.
I'm using a short diy cable by canare built by a sna'er so may be able to to find it's value too. Is there a way of adding this value in some other way?
Cheers Ian.

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Guest Muon N'

Heh...I should put my tube phono back together and store it in case I ever get back into the black. Doubtful but if I don't I'll end up scavenging parts from it for other things.

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2 minutes ago, TOPSHELF said:


I'm using a short diy cable by canare built by a sna'er so may be able to to find it's value too. Is there a way of adding this value in some other way?
Cheers Ian.
 

 

Yes, whatever total capacitance you arrive at from summing my nos. 1, 2 & 3 can be added to.  If the Tron doesn't offer parallel input RCAs like, say, Joe Rasmussen's JLTi and my Muse do ... then you need to plug RCA 'T' or 'Y' connectors into the Tron input RCAs.  These give you 2 RCA sockets - so:

  • the phono cable plugs into one, and
  • a 'C-loaded' RCA plug goes into the other.

Andy

 

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6 minutes ago, Noum said:

Heh...I should put my tube phono back together and store it in case I ever get back into the black.

Sacré bleu!! :emot-bang: Actually, I know a good therapist........:lol::P

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G'day all, I trotted out my QED DS-1 phono stage tonight and yes it is a very 'nice' sounding phono stage but it doesn't play overly loud with only 31 db gain!  It would be nice if I could 'up' the gain to the 40 db range!  I'm thinking about adding a low gain stage to the output which should do the job.  Any thoughts or comments on doing this?  Regards, Felix.    

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You may change the sound Felix.

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Is that an opamp based circuit?  I would wonder if you can't just change the feedback resistor ratio to get whatever gain you need.

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G'day all, thanks for the comments.  Adding a good gain stage to the output is I think preferable as that is akin to 'turning the volume up', whilst altering the feedback components will inevitably have some effect on the desired RIAA equalisation.  I do have a suitable circuit in mind but I have a bit of thinking to do, and yes the QED DS-1 circuit is op amp based (NE5532).  Regards, Felix. 

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That one of the reasons why I prefer passive RIAA networks in between gain stages.  Makes adjusting the gain easy.  That said, I will be there is a way to do it, if you analyse the circuit involved.

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G'day all, a bit of a conundrum, as it were.  I've spent a fair bit of the day 'repairing' a few electronic DIY projects around the shack including one of my DIY phono stages based on the Bruce Heran single op amp design.  I gave it a bit of a listen after all repaired, and again I can't quite believe what a terribly 'nice' sounding phono stage it is. 

 

I could happily listen to it all day, it is just so pleasant on the ears.  Why it sounds so nice I don't know, but subjectively it outperforms much more expensive and elaborate phono stages I have!  In the end I honestly think that I'd rather have a phono stage like this than anything else, regardless of cost.  I say that because I do have another very highly regarded phono stage coming.  Will it sound as good as this one?  Regards, Felix. 

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G'day all, just a bit of an update.  Mission accomplished!  I've used the 'universal preamplifier kit' circuit configured as a straight gain stage connected to the output of the QED DS-1 and the output now is where it needs to be! 

 

I had to reduce the gain down significantly though, op amps can generate a lot of gain!  I used the supplied LM833 dual op amp as supplied with the kit, which sounds and works fine!  Regards, Felix. 

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Hi Felix,

How does the Bruce Heran opamp compare against the Rod Elliott phono stage that you are fond of?

Have you tried the/Groovewatt/OddWatt valve phono stage?

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G'day mate, yes the ESP P06 does sound nice but only with the original HF  equalisation network values used.  The updated values sound 'harsh' to my ears.  The Heran op amp design sounds 'sweeter' to my ears and very nice.  No I haven't heard any of the others.  I have a Schiit Mani coming, and I hope that it sounds 'nice'.  Regards, Felix. 

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On 11/8/2017 at 2:39 PM, aussievintage said:

That one of the reasons why I prefer passive RIAA networks in between gain stages.  Makes adjusting the gain easy.

 

Not necessarily, IME.  :(

 

If you have a passive RIAA network in between 2 gain stages (like I have with my 'Muse' phono stage) then the value of the gain resistor used on the 1st gain stage becomes part of the the calculation for the RIAA component values.  So if you increase the value of the gain resistor - you have to decrease the C values in the passive RIAA network and increase the R value(s).

 

Of course, you can increase the gain resistor on the 2nd stage without having this problem.  This should suffice for a few dB increase in gain.  :)

 

Andy

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3 minutes ago, andyr said:

 

Not necessarily, IME.  :(

 

If you have a passive RIAA network in between 2 gain stages (like I have with my 'Muse' phono stage) then the value of the gain resistor used on the 1st gain stage becomes part of the the calculation for the RIAA component values.  So if you increase the value of the gain resistor - you have to decrease the C values in the passive RIAA network and increase the R value(s).

 

Of course, you can increase the gain resistor on the 2nd stage without having this problem.  This should suffice for a few dB increase in gain.  :)

 

Andy

Not sure what you are getting at here Andy, hard without a diagram, but gain is determined by a resistor ratio, so not sure which resistor you call the "gain resistor". Anyway you can always choose a design where the passive filter only sees a high impedance input of the next opamp gain stage that is independent of the gain chosen.

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4 minutes ago, aussievintage said:

Not sure what you are getting at here Andy, hard without a diagram, but gain is determined by a resistor ratio, so not sure which resistor you call the "gain resistor". Anyway you can always choose a design where the passive filter only sees a high impedance input of the next opamp gain stage that is independent of the gain chosen.

Sorry, av - I guess things are organised differently for op-amp based (vs. discrete - eg. JFET) circuits.  My gain stages have a resistor going from the JFET Drains to either the +DC rail (MM) ... or ground (MC) - for both 1st & 2nd gain stages.  The value of this one gain resistor determines the gain.

 

Andy

 

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4 hours ago, andyr said:

If you have a passive RIAA network in between 2 gain stages (like I have with my 'Muse' phono stage) then the value of the gain resistor used on the 1st gain stage becomes part of the the calculation for the RIAA component values.  So if you increase the value of the gain resistor - you have to decrease the C values in the passive RIAA network and increase the R value(s).

 

Of course, you can increase the gain resistor on the 2nd stage without having this problem.  This should suffice for a few dB increase in gain.  :)

Andy is the above applicable to my "Muse"? A few db increase in gain might go well with my new #9 speed controller soooon to be installed?

@ericd

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59 minutes ago, djb said:

 

Andy is the above applicable to my "Muse"? A few db increase in gain might go well with my new #9 speed controller soooon to be installed?

 

 

I can certainly increase your gain, David - but I'd need to turn your v2 circuit into at least v3 ... so there's a bit of work involved.  :)

 

59 minutes ago, djb said:

... might go well with my new #9 speed controller soooon to be installed?

@ericd

 

Yes, Cameron (O ye of little faith!  :lol: ) - Steve said I would get my "TCI" before Christmas - so David should be up and running shortly afterwards!  :)

 

Andy

 

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G'day all, I was doing some interesting internet reading last night especially by a certain reviewer who writes interesting reviews mainly on phono stuff.  His reviews tend to be largely non technical and concentrating on sound quality, an approach that I have some issues with, but there is no doubt that gentleman does 'listen' very well, and I find myself mostly in agreement with a lot of his review comment. 

 

One thing that I personally agree with is his notion of audio 'colour'.  Shades of synesthesia perhaps, but over the years I have certainly perceived colour/B&W invoked in the 'sound' of audio gear.  I honestly can't say why, but for example valve gear often invokes 'colour' in its sound to me, but not always valve gear.  Certain op amps have done the same thing! 

 

A specific example, my new Schiit Mani phono stage invokes colour in its playback in a very engaging and pleasant way!  Another phono stage I have invokes B&W/monochrome in a very apparent way.  As it stands, although it sounds very clean it simply doesn't sound at all musical to me at all.  Weird, but interesting.  Anybody else perceive the same sort of thing with audio gear?  Regards, Felix.    

Edited by catman
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Certain audio equipment evokes "warmth" and "naturalness" to me, whereas other equipment doesn't (including many I heard at the HiFi show which were enthusiastically received by others).  I don't have synesthesia or shades of it, but I find it a fascinating experience (trying to understand what I can't experience).  So I'm curious Felix, when you listen to an equipment combination that evokes "colour", is there some music which you can play which reverts it to monochrome?

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G'day mate, to answer your question no, not really.  Things tend to stay fairly constant in that respect.  I will add that live acoustic music always invokes 'colour' to me as I listen.  Regards, Felix. 

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G'day all, well that should be obvious....one day I will list them all and shock everyone, myself included!  Anyway back on topic, I fired up my Rothwell Audio 'Simplex' this evening, a phono stage that gets little use these days and listening to it now playing Hendrix I wonder why, as it sounds fantastic! 

 

When I first bought it I thought it somewhat overpriced but maybe there is a very good reason for it, it does sound fantastic.  However maybe it sounds a little too fantastic, which makes me wonder about the accuracy of the RIAA curve?  Mated with my Shure M97xE (a cartridge with a slight and deliberate upper treble roll off), that cartridge shows absolutely no sign of any treble roll off whatsoever, and I do wonder why?

 

The specs indicate plus/minus .5 db RIAA accuracy which seems accurate enough, or maybe it is just a really well designed and great sounding phono stage based entirely on discrete transistor circuitry.  Well in the end, it sounds great with my Shure M97xE so what am I talking about?  Regards, Felix.        

Edited by catman
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