True Mono from a Stereo cartridge - switchable !

[Coffee Phil]

Well Steve,

That I should chill is probably the most intelligent you have said in this string yet. Why should I care if you think my phono stage design is competent or not?

You did not criticize my design? How about this:

"the best electronics are no electronics,besides stanton(old stanton!) probably know(knew) more about reproducing stereo and mono than anybody posting on here,if they thought doing it using electronics was better they would have advised folk to do so,perhaps you like what the electronics are adding?"

It appears that you are suggesting that I like the coloration my circuit is adding.
It turns out that if I use my GE RPX cartridge (as "true mono" a cartridge as you are likely to find) and play it through my phono stage set to RIAA then switch to the internal stereo phono stage in my Hafler DH 100 I can hear no difference. Most of us regard the late David Hafler to be a very competent audio equipment designer.

Even if a person is only interested in mono Lps the choice of playback EQ is a nice thing to have as the RIAA did not standardize on what was the RCA New Orthophonic curve until ~1955. Stereo Lps became available about 3 years after that. A good many mono Lps are EQed to standards other than RIAA. Do you need to be able to select EQ? Of coarse not. The other curves were not all that vastly different and I doubt that most people would notice the difference without switching back and forth in real time.

Phil


I was assuming that most folk who wanted to listen to mono already had a phono-stage with equalisation,99.9% will be riaa though,not ideal for ancient recordings is it,your terribly touchy on this,I haven't even criticized you or your circuit,perhaps you need a chill pill or something?[/quote]

[Coffee Phil]

Hi ld,

Thanks!

Is my memory failing or are you the one who is experimenting with variations on the Barney Oliver virtual ground input phono stage? The thought came into my head that your configuration of putting the two channels of the cartridge in series should work pretty well into one of those stages. The Thevenin equivalent of the series connected cartridge will be two voltage sources in series with twice the impedance of one channel.

Thanks again,

Phil

If I was CP and had posted a perfectly good, original, flexible preamp schematic which implements features one can't find at any reasonable price and would be rare anyway, I think I would be offended too...........

CP's preamp looks very good to me, is well thought out and does what one wants. That schematic is of enduring interest, for sure.

And if one doesn't listen to mono recordings, one is missing out bigtime, IMO !

[steve195527]

Well Steve,

That I should chill is probably the most intelligent you have said in this string yet. Why should I care if you think my phono stage design is competent or not?

You did not criticize my design? How about this:

"the best electronics are no electronics,besides stanton(old stanton!) probably know(knew) more about reproducing stereo and mono than anybody posting on here,if they thought doing it using electronics was better they would have advised folk to do so,perhaps you like what the electronics are adding?"

It appears that you are suggesting that I like the coloration my circuit is adding.
It turns out that if I use my GE RPX cartridge (as "true mono" a cartridge as you are likely to find) and play it through my phono stage set to RIAA then switch to the internal stereo phono stage in my Hafler DH 100 I can hear no difference. Most of us regard the late David Hafler to be a very competent audio equipment designer.

Even if a person is only interested in mono Lps the choice of playback EQ is a nice thing to have as the RIAA did not standardize on what was the RCA New Orthophonic curve until ~1955. Stereo Lps became available about 3 years after that. A good many mono Lps are EQed to standards other than RIAA. Do you need to be able to select EQ? Of coarse not. The other curves were not all that vastly different and I doubt that most people would notice the difference without switching back and forth in real time.

Phil


I was assuming that most folk who wanted to listen to mono already had a phono-stage with equalisation,99.9% will be riaa though,not ideal for ancient recordings is it,your terribly touchy on this,I haven't even criticized you or your circuit,perhaps you need a chill pill or something?

[/quote]

just suggesting that someone liked what any circuit may add to the sound isn't meant as a criticism its meant to suggest some folk do like what a circuit adds to a sound,perhaps you need to realise the post you quoted wasn't aimed at you or in response to you it was in response to ld and just a general comment,I'm sorry if you're offended but try to stop taking things so personally

[Ldg]

just suggesting that someone liked what any circuit may add to the sound isn't meant as a criticism its meant to suggest some folk do like what a circuit adds to a sound,perhaps you need to realise the post you quoted wasn't aimed at you or in response to you it was in response to ld and just a general comment,I'm sorry if you're offended but try to stop taking things so personally

I think if you realised what the difference is between CP's preamp and the parallel wiring method you advocate, you'd simply retract. And, in any event, it's your loss if you don't see it.......!

[Ldg]

Is my memory failing or are you the one who is experimenting with variations on the Barney Oliver virtual ground input phono stage? The thought came into my head that your configuration of putting the two channels of the cartridge in series should work pretty well into one of those stages. The Thevenin equivalent of the series connected cartridge will be two voltage sources in series with twice the impedance of one channel.

Yes, that's me. Except my variation isn't virtual ground ! But either way, I agree this would really suit series wired mono in principle. The thought had crossed my mind....... !

[steve195527]

just suggesting that someone liked what any circuit may add to the sound isn't meant as a criticism its meant to suggest some folk do like what a circuit adds to a sound,perhaps you need to realise the post you quoted wasn't aimed at you or in response to you it was in response to ld and just a general comment,I'm sorry if you're offended but try to stop taking things so personally

I think if you realised what the difference is between CP's preamp and the parallel wiring method you advocate, you'd simply retract. And, in any event, it's your loss if you don't see it.......!

retract in what way?besides for somebody who just seems to contradicts everything dlaloum (is that his name?)just seemingly either to wind him up or just for the sake of it don't you think you have a nerve saying should retract something I haven't even done?:-I just feel if that is the method that the folk who actually make the cartridges recommend then that is what I would use(notice I said I:-not saying you or Phil should!),just think the other methods seem rather complex considering the signal quality to start with

[Ldg]

....considering the signal quality to start with

Then, you do not know mono.

You are mostly trolling, steve195527. Which is a pity because this thread has some good content IMO.

[steve195527]

....considering the signal quality to start with

Then, you do not know mono.

You are mostly trolling, steve195527. Which is a pity because this thread has some good content IMO.

not trolling at all,but when your friend takes the hump and asks do I know what equalisation is or even a phono stage??doesn't that sound rather childish?And you take the hump because I point out you history with a certain other member and accuse me of trolling,unless of course you regard trolling as somebody not thinking you are 100% correct?seems rather odd

[Ldg]

@ ld,
Thanks. One could also fasten a little "mono" label on the headshell to make it more distinctive Italic lettering would be easily readable (Old English would be hard to read). That's for Calligraphy mavens See: http://www.ehow.com/calligraphy/

b50

B_50, I think it may be possible to include series resistors in the headshell too, to accomodate standard preamp RC loading, and hence work around the need for preamp laoding mods. A few swift simulations seem to show it works. Watch this space !

[Coffee Phil]

H Steve,

You are taking offence that I question if you know what EQ is or a phono stage is after posting this:

"Oh yes,don't use any EQ or even any gain! don't be so touchy and I still think Stanton will know,probably forgotten!, more about reproducing mono and stereo than you,just saying they advised a far simpler solution,how many records play mono vertically??"

A good many of us here are aware that most MM (and MI and variable reluctance) cartridges require ~30 dB of gain at 1 kHz to get to line level and equalization to complement the record EQ and convert the velocity response of the mag cartridge to an amplitude response.

All designs are a compromise to optimize the goals of the designer. If I were working for Stanton (or any other cartridge manufacturer) and my boss came to me and said I need a circuit which can be implemented on our existing products by our customers at little cost or effort there is little doubt that I would say just put the channels in parallel. Does it work? Fairly well. Is it optimum? Not really, for the reasons ld outlined.

ld put his coils in series to address the issues he stated in the parallel approach. He is not the first to do that or the only one. The person who provided a 3 mill stylus for my Sonus cartridge is a big proponent of the series connection.
Joe pointed out how the series connection will raise the output impedance of the cartridge and cause capacitive loading of the cables and preamp to be an issue. ld then pointed how he mitigated that issue.

Now my goals.

1. accurate summing of the channels for mono
2. ease of switching from lateral to vertical
3. load on each channel of cartridge the same as the stereo phono stage it was designed for
4. Choice of play back EQ
5. Easy switching from mono to existing stereo phono stage.
6. Ability to switch from left channel, right channel, or the sum when in mono

I think my design addressed all of the above goals.

Am I as smart as the Stanton Engineers? Who knows.

Am I a reasonably competent engineer? Well I hope so. I do have a BSEE and now have for the most part retired after a career of designing RF and analog circuits. I have been an audiophile for most of my life and have designed several amplifiers and preamps for my use.

Phil

....considering the signal quality to start with

Then, you do not know mono.

You are mostly trolling, steve195527. Which is a pity because this thread has some good content IMO.

not trolling at all,but when your friend takes the hump and asks do I know what equalisation is or even a phono stage??doesn't that sound rather childish?And you take the hump because I point out you history with a certain other member and accuse me of trolling,unless of course you regard trolling as somebody not thinking you are 100% correct?seems rather odd

[Ldg]

I was following that string with interest. Now I can't seem to find it. Could you post the link?

Yes, it's here : viewtopic.php?t=38520

They're a series of schematic sketches for development, and they start to perform/sound pretty well after version 2.1 and the bias element disappeared. Version 3 has a method for suiting a wide range of MM/MI carts without rejigging the whole 1st stage filters, I think that's not a bad place to start. And input to it always is very welcome, CP. The Barney Oliver schematic and links to those resources is there too.

[Coffee Phil]

Hi ld,

Thanks. I started looking through it but now have to do real work. I've bookmarked it so now I can find it with ease.

By the way both your Mark 1 and Mark 2 versions look pretty virtual ground input to me. The virtual ground is a fine summing node so parallel connected channels in the cartridge should work fine with little interaction between them. This should please those who want to connect their cartridge channels in parallel unless they also es·chew electronics.

Needless to say for mono you would only use one of these phono stages and connect its output to both channels of your stereo system.

Phil

I was following that string with interest. Now I can't seem to find it. Could you post the link?

Yes, it's here : viewtopic.php?t=38520

They're a series of schematic sketches for development, and they start to perform/sound pretty well after version 2.1 and the bias element disappeared. Version 3 has a method for suiting a wide range of MM/MI carts without rejigging the whole 1st stage filters, I think that's not a bad place to start. And input to it always is very welcome, CP. The Barney Oliver schematic and links to those resources is there too.

[steve195527]

[quote="Coffee Phil"]H Steve,


"Oh yes,don't use any EQ or even any gain! don't be so touchy and I still think Stanton will know,probably forgotten!, more about reproducing mono and stereo than you,just saying they advised a far simpler solution,how many records play mono vertically??"

A good many of us here are aware that most MM (and MI and variable reluctance) cartridges require ~30 dB of gain at 1 kHz to get to line level and equalization to complement the record EQ and convert the velocity response of the mag cartridge to an amplitude response.

All designs are a compromise to optimize the goals of the designer. If I were working for Stanton (or any other cartridge manufacturer) and my boss came to me and said I need a circuit which can be implemented on our existing products by our customers at little cost or effort there is little doubt that I would say just put the channels in parallel. Does it work? Fairly well. Is it optimum? Not really, for the reasons ld outlined.

ld put his coils in series to address the issues he stated in the parallel approach. He is not the first to do that or the only one. The person who provided a 3 mill stylus for my Sonus cartridge is a big proponent of the series connection.
Joe pointed out how the series connection will raise the output impedance of the cartridge and cause capacitive loading of the cables and preamp to be an issue. ld then pointed how he mitigated that issue.

Now my goals.

1. accurate summing of the channels for mono
2. ease of switching from lateral to vertical
3. load on each channel of cartridge the same as the stereo phono stage it was designed for
4. Choice of play back EQ
5. Easy switching from mono to existing stereo phono stage.
6. Ability to switch from left channel, right channel, or the sum when in mono

I think my design addressed all of the above goals.

Am I as smart as the Stanton Engineers? Who knows.

Am I a reasonably competent engineer? Well I hope so. I do have a BSEE and now have for the most part retired after a career of designing RF and analog circuits. I have been an audiophile for most of my life and have designed several amplifiers and preamps for my use.

Phil


[

Phil
If you can't tell that I was being sarcastic perhaps you need to get out more?sorry if I offended you,I din't mean to but seems you're going to take whatever I write the wrong way,no probs carry on fiddling with things

[Coffee Phil]

Hi Steve,

I get out plenty. I also get sarcasm. You probably don't want to get into a sarcasm match with me. My wife is constantly on me to curb it so I will be fit to be around civilized people.

I question if you get sarcasm or tolerate it well as you seemed to take offense at the amount I dumped on you.

Examples:

To your - Electronics Bad! I asked how you were connecting your phono cartridge to your speakers without the benefit of electronics.

To your - EQ Bad! I questioned if you knew what a phono stage is.

To your - Gain Bad! I pointed out that most of us realize that you need a fair bit of it to get from the level out of your cartridge to line level.

Now you may say that you didn't realize that my phono stage was a stand alone phono stage to be used instead of the stereo phono stage as opposed to in front of it. I did put up the schematic of it and a description. If you didn't understand what it is you could ask before coming up with statements like the Stanton engineers have forgotten more stuff than I am likely to ever know.

Your apology is accepted.

Phil

H Steve,


"Oh yes,don't use any EQ or even any gain! don't be so touchy and I still think Stanton will know,probably forgotten!, more about reproducing mono and stereo than you,just saying they advised a far simpler solution,how many records play mono vertically??"

A good many of us here are aware that most MM (and MI and variable reluctance) cartridges require ~30 dB of gain at 1 kHz to get to line level and equalization to complement the record EQ and convert the velocity response of the mag cartridge to an amplitude response.

All designs are a compromise to optimize the goals of the designer. If I were working for Stanton (or any other cartridge manufacturer) and my boss came to me and said I need a circuit which can be implemented on our existing products by our customers at little cost or effort there is little doubt that I would say just put the channels in parallel. Does it work? Fairly well. Is it optimum? Not really, for the reasons ld outlined.

ld put his coils in series to address the issues he stated in the parallel approach. He is not the first to do that or the only one. The person who provided a 3 mill stylus for my Sonus cartridge is a big proponent of the series connection.
Joe pointed out how the series connection will raise the output impedance of the cartridge and cause capacitive loading of the cables and preamp to be an issue. ld then pointed how he mitigated that issue.

Now my goals.

1. accurate summing of the channels for mono
2. ease of switching from lateral to vertical
3. load on each channel of cartridge the same as the stereo phono stage it was designed for
4. Choice of play back EQ
5. Easy switching from mono to existing stereo phono stage.
6. Ability to switch from left channel, right channel, or the sum when in mono

I think my design addressed all of the above goals.

Am I as smart as the Stanton Engineers? Who knows.

Am I a reasonably competent engineer? Well I hope so. I do have a BSEE and now have for the most part retired after a career of designing RF and analog circuits. I have been an audiophile for most of my life and have designed several amplifiers and preamps for my use.

Phil


[

Phil
If you can't tell that I was being sarcastic perhaps you need to get out more?sorry if I offended you,I din't mean to but seems you're going to take whatever I write the wrong way,no probs carry on fiddling with things