Pundit
Post by LinnBoy on May 30, 2017 13:34:27 GMT 12
Power supply and bearing - Lingo, Hercules, Cirkus etc. Or anything. What you got lying' around?
I am a non-recovering audioholic, and Ivor is my higher power.
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Post by Graham on Jun 1, 2017 12:50:56 GMT 12
How about a Geddon Clone. Many LP12 users prefer them to the more complex and expensive PSU options, but only one speed. I have used one on my Thorens and AR turntables and could whip one up for you if interested. Cheers Graham
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Post by Owen Y on Jun 1, 2017 15:35:36 GMT 12
I've heard it said that the best sounding LP12 is the very first generation. Sucessive iterations begin to lose some of the LP12 'magic'. My 1st LP12 was 'upgraded' to a Valhalla PSU fairly early on & I don't recall much about that change, but the 'Basik' PSU I believe is just a resistor + cap, 'Permanent Split Capacitor' (PSC) that is common on TTs that use similar motors, eg the Rega Planar (which uses the same Philips/Premotec/Airpac AC motor). Maybe there is something about keeping an AC mtr driven TT's PSU simple, that contributed to the success of the sound of the Rega Planar - and maybe why some contend that the original LP12 sounded 'special'? What I do recall, is that I did install add a Lingo PSU to my LP12 & it wasn't long after that I sold it & the LP12. IMO, yes, the Lingo removed some of the 'magic', the LP12 sounds a bit more 'digital', more 'controlled', less lively & dynamic. As I found when restoring my nephew's Rega 3 TT, the best thing that can be done with those mtr circuits, is to finely tune the resistor value in order to 'balance' the motor coils to minimise vibration. This is the Premotec datasheet: (The 230v cct is at bott RHS.)
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Post by Owen Y on Jun 1, 2017 15:39:55 GMT 12
From what I can see, this is the 'Armageddon' type PSU circuit:
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Post by Owen Y on Jun 1, 2017 15:53:00 GMT 12
As can be seen, the RHS part (R, cap, mtr) is same as the Basik 'PSC' citcuit. The main difference is the insertion of a step-down PTX. Why?
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Post by michaelw on Jun 1, 2017 16:02:06 GMT 12
I've heard it said that the best sounding LP12 is the very first generation. Sucessive iterations begin to lose some of the LP12 'magic'. agreed ! an early lp12 with big red power button, grace 707 was hard to beat for sheer foot tapping musical enjoyment. every couple of years i wonder who bought my old modded linn ...
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Post by Graham on Jun 1, 2017 16:34:58 GMT 12
As can be seen, the RHS part (R, cap, mtr) is same as the Basik 'PSC' citcuit. The main difference is the insertion of a step-down PTX. Why? Sometimes the simplest solutions are the best. That big mutha torroidal transformer is claimed to act as an isolation transformer and does a good job of absorbing some of the mains hash for smoother motor operation. The one I built and used had a 500va torroidal with 100v output. This was stepped down to 85-90 volts with a suitable resistor ( same output as a Valhalla) to further reduce the inherent vibration from cogging in the synchronous motor. It certainly sounded as good, if not better, than the Valhalla based PSU I was using on my Thorens and the AR turntables. Cheers
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Post by michaelw on Jun 1, 2017 17:06:09 GMT 12
500va ! That's bigger than many amplifiers
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Post by Owen Y on Jun 1, 2017 17:17:22 GMT 12
Hi Graham - TXs do block some mains noise, but mainly outside their bandwidth, ie EHF hash. TXs I believe are v food at transferring within their bandwidth. One of the best things that can be done with these 'basic' PSC mtr ccts is to 'balance' the voltages across the 2 mtr coils, in order to reduce vibration. I did this on the Rega, but you need to 'trim' the R, as per Premotec recommendations: TT manufs simply choose the nearest resistor from commonly available values & it takes a bit of testing to come up with the right value.
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Post by Graham on Jun 1, 2017 17:48:17 GMT 12
Agreed. I did experiment like you did with difference phasing cap values while holding the motor in my hand. I found in my two instances the 0.22 cap was as good as any. The biggest reduction in felt vibration was from the reduction in voltage. 80 volts was even better but the motor started to struggle at start up.
Sorry if we are hijacking your Wanted thread LinnBoy.
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Post by Owen Y on Jun 1, 2017 17:57:27 GMT 12
[Yes, sorry about digression LinnBoy ]
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Pundit
Post by LinnBoy on Jun 3, 2017 8:53:41 GMT 12
This is great digression! Although I have no real idea what on earth ANY of you are talking about! Mine still has the original red power button, and I am always amazed at how good it sounds. Be very keen to look at options though, tell me more 'bout this Geddon clone etc.
I am a non-recovering audioholic, and Ivor is my higher power.
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Post by Owen Y on Jun 3, 2017 10:27:28 GMT 12
Hi LinnBoy - your Basik PSU may still sound the best! (If you can, post a pic of what it looks like, underneath.) Graham probably know more, but unless I'm mistaken, the circuit is as per image above, essentially inserting a big toroidal PTX in front of pretty much the same as the Basik circuit. Looks something like this: If implementing this, I would leave your existing circuit in place, so that you can compare & if desired, restore the original.
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Post by Graham on Jun 3, 2017 20:52:58 GMT 12
This is my version of the Geddon Clone PSU which will work with any synchronous turntable motor designed to run on 115volts AC. I have the phasing capacitor and dropping resistor inside so all that is needed is to connect the 3 wires directly to the motor using the terminal block. We are dealing with mains voltage here so it is fused and the transformer and metal case are earthed for safety. It is a seriously heavy mutha weighing in at 3 kg due to the oversized torroidal transformer.
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Pundit
Post by LinnBoy on Jun 4, 2017 8:16:21 GMT 12
Installed numerous Valhalla's and Lingos, always a distinct inprovement. Ditto bearings, particularly the Cirkus. Matter of preference I suppose. How much would a HeftyGeddonCLone set me back?
I am a non-recovering audioholic, and Ivor is my higher power.
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Post by Graham on Jun 4, 2017 10:04:53 GMT 12
Hi LinnBoy.
How does $150 sound for the one pictured above ? Freight to the deep south ( Dunedin ? ) would be about $28 according to NZ Post calculator. I would supply specific instructions as to how it must be wired up, but it is not difficult.
Cheers Graham
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Pundit
Post by LinnBoy on Jun 5, 2017 7:19:26 GMT 12
That sounds pretty reasonable - SOLD! Does one PM in this forum? I will give it a try.
I am a non-recovering audioholic, and Ivor is my higher power.
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Pundit
Post by LinnBoy on Jun 14, 2017 11:36:10 GMT 12
Installed the 'Geddon on Friday. Also stripped system and tidied it up. Sondek sounded awful! Turns out, whole system sounds awful, so I am looking forward to working out what occurred. Was away watching the Northern poofs learn how to play rugby, so I will keep you updated.
I am a non-recovering audioholic, and Ivor is my higher power.
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Post by Owen Y on Jun 14, 2017 12:01:51 GMT 12
Oops... Rule #1: Never change more than one thing at a time. It's hard not to break that rule
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