I grew up in the stereo era too. But it was discovery of a 1953 recording/pressing that seriously rocked my boat, because even in studio terms it works as a convincing reproduction, amazingly so. Which I didn't discover until the mid noughties.
Call me a cynic, but the stereo initiative had a side effect that new equipment (and x2 of it!) had to be bought en mass. And for the great unwashed who seldom configured equipment in the room to realise a meaningful image anyway, it provided a 'different' but not necessarily more faithful experience of the recording.
It's a different and IMO better experience to listen to the original mono mix of sgt pepper on a single mono corner speaker than the original stereo mix on a stereo rig.
Only in recent times with mass use of headphones has stereo come into its own, but that's still as a production tool for spatial exploitation rather than fidelity in the original sense of the 50s. I mean the spatial layout of a typical recent rock drum kit is hardly realistic...……..
Suggestion is: try a mono corner speaker with a quality classical mono recording from the champagne Charlie days. Whacking mono through 2 separate speakers isn't really the way is was ever intended to be heard.
HTH!
LD
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When the cartridge is properly wired for mono, i.e. in series, a very clear and focused image appears between the speakers. If your input is single-ended this will double the inductance so you may need to take care with input capacitance. I use a differential input so this is not an issue for me.
LD, is your copy of the Richard Strauss the pink 12 inch or the yellow 10 inch? The reason I ask is that I don't recall seeing a copy of the 12 inch that was RIAA.
Kevin, the American 50's catalogue is utterly wonderful if you haven't explored it.
LD, is your copy of the Richard Strauss the pink 12 inch or the yellow 10 inch? The reason I ask is that I don't recall seeing a copy of the 12 inch that was RIAA.
Kevin, the American 50's catalogue is utterly wonderful if you haven't explored it.
Hi piano3, yes I strongly prefer the result of series wiring over other methods, and you're right about the image. A few years back I worked out a simple way of wiring and switching between normal stereo and series wired mono with just a DPDT switch. This can be conveniently done at the plinth end of tonearm wiring, generally under the plinth, and I've used it for years.
Attached schematic for switchable series wiring. You're right about inductance too - for normal preamps it needs a switchable R load at the preamp end between 47k (or whatever) and 100k (or 2x whatever) approximately. It should be adaptable for balanced input preamps.
For those of us Jedi who have transcended inductance, it's not OK to connect L&R preamp inputs together in transimpedance loading, so this switching won't work and if one wishes to use both amp channels for mono one also needs to have a switch in the preamp to sort it out.
The recording that started this mono kick for me is the 1953 Decca LW 5056 and its on 10" black vinyl.
And yes, Galu, an aspidistra on top of a corner speaker makes all the difference 😉
LD
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I was obviously so addicted to solder fumes a few years back that I built half a dozen different phono amps for stereo/mono/78, MM/MC so my cartridge wiring is done at the pins of the input XLR's.
LD, if your pressing of LW5056 is really 1953 then you might want to try 50 rather than 75 uS for the treble de-emphasis. Decca didn't go to RIAA until about the spring of 1955.
LD, if your pressing of LW5056 is really 1953 then you might want to try 50 rather than 75 uS for the treble de-emphasis. Decca didn't go to RIAA until about the spring of 1955.
@ luckythedog
You guys sure go to amazing lengths to derive pleasure from your mono masterpieces!
My mono LP collection is not at all sophisticated, and merely consists of some originals from the early 1960s, with the odd charity shop find thrown in.
I play them with a stereo cartridge (0.6 mil conical stylus) via my Rogers HG88 Mk III valve integrated amplifier, which provides a 'Disc Mono' setting on its input selector.
However, the amp also has a function selector which provides for mono operation through both output channels from either input channel.
Assuming it would make a worthwhile difference in my circumstances, can you recommend an affordable mono cartridge with which to make use of the latter facility?
Thanks.
You guys sure go to amazing lengths to derive pleasure from your mono masterpieces!
My mono LP collection is not at all sophisticated, and merely consists of some originals from the early 1960s, with the odd charity shop find thrown in.
I play them with a stereo cartridge (0.6 mil conical stylus) via my Rogers HG88 Mk III valve integrated amplifier, which provides a 'Disc Mono' setting on its input selector.
However, the amp also has a function selector which provides for mono operation through both output channels from either input channel.
Assuming it would make a worthwhile difference in my circumstances, can you recommend an affordable mono cartridge with which to make use of the latter facility?
Thanks.
Showing my age, but when Sgt. Pepper came out my cartridge was still mono, so I bought the mono version of the LP.
I had a 10 watt mono valve amp and a 12" speaker in a 5 cu ft reflex cabinet - placed where else but in the corner!
Did I miss out by not having a stereo copy? Did I heck! 😎
I'm not far behind you. just no 78s. But I have a huge pile of reed relays lined up for switching duty when I get time to hook it all up.
@Galu: what is the input on the Rogers? Assume MM rather than ceramic?
@ Bill
The Rogers amp has plug in modules for both MM and ceramic cartridges - gold for MM and silver for ceramic.
(I used to run a Decca Deram into the latter. The cartridge is long lost, but fondly remembered!)
silver | A60man | Flickr
I don't want to waste anyone's time here, as I obviously lie on the fringes in respect of my mastery of matters mono!
I suppose I'm just looking for reassurance that the conversion of the cartridge signal to mono provided by my Rogers amp is an adequate approach to playing mono LPs at my 'amateur' level.
The circuit diagram of Rogers HG88 Mk III is attached for your reference.
The Rogers amp has plug in modules for both MM and ceramic cartridges - gold for MM and silver for ceramic.
(I used to run a Decca Deram into the latter. The cartridge is long lost, but fondly remembered!)
silver | A60man | Flickr
I don't want to waste anyone's time here, as I obviously lie on the fringes in respect of my mastery of matters mono!
I suppose I'm just looking for reassurance that the conversion of the cartridge signal to mono provided by my Rogers amp is an adequate approach to playing mono LPs at my 'amateur' level.
The circuit diagram of Rogers HG88 Mk III is attached for your reference.
Attachments
Galu, if you are playing mono records from the 60's then I think any specialised cartridge/stylus may be of doubtful benefit. You will get real benefit from the cartridge wiring, output from left hot and right ground with left ground and right hot connected together. Ideally, then into a single channel RIAA preamp with the output of this into both power channels. This avoids messing up the signal with imperfectly matched RIAA filter components.
Deram was a good cartridge. Very clever design. And don't worry I am a rank amatuer compared to Piano and LD as well. I just like building stuff (and getting stuff built).
The usual suspects that work into MM inputs are the DL-102 and AT-mono3/LP. But a mono strapped MM is a good starting point IF you can adjust your azimuth suitably tight otherwise you lose a lot of the vertical cancellation. I recently aquired (but not used yet) a technics/panasonic EPC-250CII-L (and breathe). This is unusual in having only 85mH inductance and was designed to reduce issues with phono stage loading. That might be a good candidate for mono use and can lend it to you if you want to experiment. My 40mH AT-25 is however off limits for now 🙂.
The usual suspects that work into MM inputs are the DL-102 and AT-mono3/LP. But a mono strapped MM is a good starting point IF you can adjust your azimuth suitably tight otherwise you lose a lot of the vertical cancellation. I recently aquired (but not used yet) a technics/panasonic EPC-250CII-L (and breathe). This is unusual in having only 85mH inductance and was designed to reduce issues with phono stage loading. That might be a good candidate for mono use and can lend it to you if you want to experiment. My 40mH AT-25 is however off limits for now 🙂.
Lovely as it may be, the internal mono switch isn't optimal for using stereo cartridges to play mono records: it doesn't sum the channels, it applies one or other channel to both sides.
It must be possible to rewire SW3a and SW3b so as to sum the channels, just doesn't spring to mind immediately.
LD
@piano3
I understand the benefit a single RIAA preamp would bring, but doubt if I would notice the difference when playing my Shadows records! However, I may give this a whirl when I pick up a spare headshell for experimentation purposes. Thanks for your suggestion.
@ billshurv
Currently playing my old monos on a Garrard SP25 Mk II (please don't laugh!) which I've recently refurbished. Due to some peculiar tilt manufactured into the tone arm bearings, the azimuth varies as a function of the distance of the stylus from the record spindle, so my verticals will be very poorly cancelled!
Now, by this point you will be raising your arms in horror, but I find it all a bit of nostalgic fun! Thanks for your generous offer (which, no doubt, has been hastily withdrawn!). I'll get back when I've got a better turntable!
(The story actually gets worse, my other tables are Technics T4Ps!! 😱)
@luckydog
Thanks for your information regarding the mono switch (it's on the facia by the way - see Radio Museum link below for photos).
HG88 Mk III Ampl/Mixer Rogers, Catford see also Rogers Birmi
I understood the 'Disc Mono' setting on the input selector would sum the two inputs from a stereo cart.
I also understood that, by plugging a mono cartridge into one of the inputs, I could use the function selector to direct it to both output channels.
Is that in accord with your interpretation of the switching arrangements?
I understand the benefit a single RIAA preamp would bring, but doubt if I would notice the difference when playing my Shadows records! However, I may give this a whirl when I pick up a spare headshell for experimentation purposes. Thanks for your suggestion.
@ billshurv
Currently playing my old monos on a Garrard SP25 Mk II (please don't laugh!) which I've recently refurbished. Due to some peculiar tilt manufactured into the tone arm bearings, the azimuth varies as a function of the distance of the stylus from the record spindle, so my verticals will be very poorly cancelled!
Now, by this point you will be raising your arms in horror, but I find it all a bit of nostalgic fun! Thanks for your generous offer (which, no doubt, has been hastily withdrawn!). I'll get back when I've got a better turntable!
(The story actually gets worse, my other tables are Technics T4Ps!! 😱)
@luckydog
Thanks for your information regarding the mono switch (it's on the facia by the way - see Radio Museum link below for photos).
HG88 Mk III Ampl/Mixer Rogers, Catford see also Rogers Birmi
I understood the 'Disc Mono' setting on the input selector would sum the two inputs from a stereo cart.
I also understood that, by plugging a mono cartridge into one of the inputs, I could use the function selector to direct it to both output channels.
Is that in accord with your interpretation of the switching arrangements?
I did get a shadows record for research purposes as, according to the loudness database it is one of the higher DR records you can get (Walkin' with the shadows). I haven't ripped it yet to find out but would be (pleasantly) suprised if the numbers were correct. (and yes I know it's stereo).
I am sure all of us in the UK at some point have had an SP-25 in the family. I used to love watching the stacking mechanism at work 🙂. Offer still remains. On anything cheap and older than my wife I see upgrade opportunities if things get damaged 🙂.
I am sure all of us in the UK at some point have had an SP-25 in the family. I used to love watching the stacking mechanism at work 🙂. Offer still remains. On anything cheap and older than my wife I see upgrade opportunities if things get damaged 🙂.
Bill, you're thinking of the AT6 (Automatic Turntable), but the mark 1 (and 2) SP25 (Single Player) was based on the same platform as the automatic.
Checked out 'Walkin' With The Shadows' to find it is a Music For Pleasure (MFP) compilation album. Don't have this one in my substantial Shads collection, but have most of the tracks elsewhere in glorious mono. Interesting that it has such a high dynamic range - perhaps Hank was standing on his tiptoes!
Checked out 'Walkin' With The Shadows' to find it is a Music For Pleasure (MFP) compilation album. Don't have this one in my substantial Shads collection, but have most of the tracks elsewhere in glorious mono. Interesting that it has such a high dynamic range - perhaps Hank was standing on his tiptoes!
Ah yes I missed that in the schematic, appols.
The switch simply wires L&R cartridge channels in parallel. I refer the interested to the volumes of debate about whether this is an effective way of summing channels, but in my view isn't ideal but it's a start.
Then the mono source switch should be able to be set to provide mono to both speakers.
So, IMO that arrangement can be bettered.
HTH!
LD
Ah we may have had 2 SP-25 and one of those then.
LD: I have hurt my head trying to reconcile why parallel and serial wiring should give different results. In the end I gave up and decided to just put it down to the currents only having one place to go instead of two 🙂
LD: I have hurt my head trying to reconcile why parallel and serial wiring should give different results. In the end I gave up and decided to just put it down to the currents only having one place to go instead of two 🙂
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I think almost every loft has at least one SP-25 in it.....😉
Yes, to cut another long story short, difference signals (non-ideals) in parallel wired L&R see a low impedance reactive load, and require the generator to produce a ton of current with potentially large time/phase offset. Not all generators behave well.
In series wiring, there's hardly any current which is entirely limited by the preamp's loading. Far easier on the generator, hence the difference.
For spherical cows in a vacuum, there's no difference series or parallel. But in practice, there often is and significantly too IME. Non-ideals. Also explains the various and varying results as to differences between testers, and the raging argument. But series is always good and behaves well IME.
LD
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