How to achieve Audio Heaven

[Infinitely Baffled]

If possible, getting the loading right with the MP-500 might help. Here's a graph what different capacitive loads do to MP-11 - http://www.tnt-audio.com/jpeg/nagaok...r_response.gif - I think the body is of higher inductance than the MP-500 and stylus is obviously very different, but it gives you an idea what happens to the freq response when you adjust loading.

Thanks for this, Kai. How do you adjust the capacitative loading of a MM phono stage. As far as I can see, both the Audio Note and NVA items come built with 47kOhm resistive loading, but for capacitative loading, you get what you are given. Regards. Gary.

[Arkless Electronics]

The AN is on its way to you now, Jez. And yes, good idea to include your head amp. It might be a solution I prefer to faffing around with transformers. Actually as I write this I am listening to the AT33 playing through the (universally disliked) AT630 and the NVA phono stage which arrived in the post this afternoon. It's very good, actually - really nice - and of course it's as quiet as can be. But then solid state, you would expect it to be wouldn't you? Cheers. Gary.

Solid state is indeed quieter than valves in a phono stage, but, in the case of MM only phono stages (most valve ones are MM only) valves can be quiet enough for background noise to be no more intrusive in practice than that of a SS design.

[Barry]

Apropos SUTs, microphone transformers can be used with success since the output voltage from a microphone is of a similar order to that of a moving-coil cartridge. However the source impedance of some MC cartridges can be very low (1 Ohm for the Transfiguration 'Orpheus', and 2 Ohm for most Ortofon SPUs), whereas moving-coil microphones tend to have higher impedance. So if your chosen MC has a very low impedance, you really need to use a microphone transformer designed for use with ribbon microphones, as these do have a low resistance.

I have used Haufe transformers successfully with the Denon 103, but the Haufe unit (T7883) was designed to work with the 40Ohm coil resistance of the Denon. EMT cartridges have a coil impedance of 22Ohm, and for these I have successfully used a 10:1 transformer made by Partridge. Many of the SUTs you see for sale on eBay use audio transformers that have been cannibalised from professional studio or broadcast equipment, without any thought that the transformer might not be suitable for use as a cartridge SUT.


Regarding the disappointing performance of your Decca Gold in the SME M2 - 9R arm, well you have moved from a very desirable combination of Decca with a damped unipivot (the Hadcock) to using an undamped arm.

The “wobble” you refer to suggests the cartridge/arm resonance is excessively high. I don’t know about the Cartridge Man’s ‘Music Maker’, but I do have a fair amount of experience with using Decca cartridges in a variety of arms, including SME.

The SME M2-9R arm has an effective mass of 9.5g. The Decca Gold has a mass of 6.7g and a dynamic compliance of 12cu in the horizontal plane and 5cu in the vertical plane. The calculated arm/cartridge resonant frequencies are 11.4Hz and 14.9Hz respectively. These are on the high side but not disastrous. Ideally you would want the two resonance frequencies to ‘straddle’ 10Hz. This means you would need to increase the total mass to ~ 30g, an increase of 13.6g.

In my system I have a Decca Gold mounted in a GB block and the two fitted into a Sumiko headshell. The whole assembly weighs 24.1g. In an SME 3009 arm, the calculated frequencies are 8.6Hz (horizontal) and 13.4Hz (vertical), and the whole is completely stable.

[Infinitely Baffled]

"The SME M2-9R arm has an effective mass of 9.5g. The Decca Gold has a mass of 6.7g and a dynamic compliance of 12cu in the horizontal plane and 5cu in the vertical plane. The calculated arm/cartridge resonant frequencies are 11.4Hz and 14.9Hz respectively. These are on the high side but not disastrous. Ideally you would want the two resonance frequencies to ‘straddle’ 10Hz. This means you would need to increase the total mass to ~ 30g, an increase of 13.6g."

Nifty calculating! Thanks for this, Barry. I am thrilled to bits with the prospect of getting the Decca cartridge working right in the SME arm. Sometimes on certain kinds of music it hits the spot so well that you could swear it's the only cartridge you'll ever need. But then, of course, curiosity takes over ...

However, for the moment, I will aim for a way of adding thirteen and a half gms of weight to the headshell. The GB clamp is handy in this regard, but what a price to buy one new! And the suppliers insist on fitting it themselves, possibly to justify the hefty cost. I have a slotted headshell on its way to me in the post which weighs more than the SME item, so that's a start. (By the way, how come SME think it is possible to set up an arm/cartridge without a slotted headshell or sliding carrier of some description? With fixed holes for the cartridge bolts there is no way of setting the stylus overhang without also changing the spindle-to-pivot distance. Very odd!) Many thanks for help. Cheers. Gary.

[Barry]

"The SME M2-9R arm has an effective mass of 9.5g. The Decca Gold has a mass of 6.7g and a dynamic compliance of 12cu in the horizontal plane and 5cu in the vertical plane. The calculated arm/cartridge resonant frequencies are 11.4Hz and 14.9Hz respectively. These are on the high side but not disastrous. Ideally you would want the two resonance frequencies to ‘straddle’ 10Hz. This means you would need to increase the total mass to ~ 30g, an increase of 13.6g."

Nifty calculating! Thanks for this, Barry. I am thrilled to bits with the prospect of getting the Decca cartridge working right in the SME arm. Sometimes on certain kinds of music it hits the spot so well that you could swear it's the only cartridge you'll ever need. But then, of course, curiosity takes over ...

However, for the moment, I will aim for a way of adding thirteen and a half gms of weight to the headshell. The GB clamp is handy in this regard, but what a price to buy one new! And the suppliers insist on fitting it themselves, possibly to justify the hefty cost. I have a slotted headshell on its way to me in the post which weighs more than the SME item, so that's a start. (By the way, how come SME think it is possible to set up an arm/cartridge without a slotted headshell or sliding carrier of some description? With fixed holes for the cartridge bolts there is no way of setting the stylus overhang without also changing the spindle-to-pivot distance. Very odd!) Many thanks for help. Cheers. Gary.

Are they still available? And if so, how much are they?

Apropos the fixed cartridge fixing holes in the S2 headshell, all SME arms use a sliding bedplate to achieve correct overhang.

[Infinitely Baffled]

Are they still available? And if so, how much are they?

Apropos the fixed cartridge fixing holes in the S2 headshell, all SME arms use a sliding bedplate to achieve correct overhang.

Apologies. I made my statement about the cost of the GB clamp from memory, but when I checked back on the Internet, I found it was the Deccapod I was remembering, not the GB clamp. The Deccapod - you probably know this - appears to function as a housing that sits between the cartridge and the headshell. As far as I can see it does not allow you to do away with that iffy-looking red plastic bracket that most folks use to mount the cartridge if they are not using a Decca tone-arm. The Deccapod is indeed still available from Divine Audio for £179 (!), the price includes fitting the pod to the cartridge and "recalibration" of the cartridge - whatever that is. Looks like the GB clamp is second-hand availability only. Do you find it an advantage?

Regarding the method of achieving cartridge alignment on an SME arm: the problem with using the sliding base plate to achieve the correct stylus overhang is that it moves the whole of the arm either closer to, or further away from, the platter so it changes the spindle-to-pivot distance at the same time. What is needed is a way of setting the two parameters independently of each other, so a sliding base plate AND a slotted headshell (or a headshell with a sliding carrier).
Cheers. Gary.

[paulf-2007]

What is a GB clamp

[struth]

Gardner Bender clamp ? Seems they are talking about rock tts so it may be something to do with the damping on that. Only ones i know are the gb cable type ones

[Barry]

Apologies. I made my statement about the cost of the GB clamp from memory, but when I checked back on the Internet, I found it was the Deccapod I was remembering, not the GB clamp. The Deccapod - you probably know this - appears to function as a housing that sits between the cartridge and the headshell. As far as I can see it does not allow you to do away with that iffy-looking red plastic bracket that most folks use to mount the cartridge if they are not using a Decca tone-arm. The Deccapod is indeed still available from Divine Audio for £179 (!), the price includes fitting the pod to the cartridge and "recalibration" of the cartridge - whatever that is. Looks like the GB clamp is second-hand availability only. Do you find it an advantage?

Regarding the method of achieving cartridge alignment on an SME arm: the problem with using the sliding base plate to achieve the correct stylus overhang is that it moves the whole of the arm either closer to, or further away from, the platter so it changes the spindle-to-pivot distance at the same time. What is needed is a way of setting the two parameters independently of each other, so a sliding base plate AND a slotted headshell (or a headshell with a sliding carrier).
Cheers. Gary.

There is nothing sacrosanct about the platter-spindle to arm-bearing distance. If you examine the theory of arm geometry, the minimisation of tangential tracking error depends upon two variables: the overhang and the offset angle. Overhang = effective arm length (stylus to pivot) - spindle to arm pivot distance.

With SME arms and the few others using a sliding bed plate, the effective arm length is kept constant and the spindle to arm pivot distance is changed to establish the corect overhang. The offset angle is also fixed.

With arms having a slotted cartridge fixing holes in the headshell, the spindle to arm pivot distance is fixed and both the effective arm length and the offset angle are changed when establishing the correct overhang.

Both methods are correct: the SME method makes it easier to achieve the best geometry; using a slotted headshell, is more difficult but is useful if you change cartridges frequently.

http://theartofsound.net/forum/showt...earm-alignment

[Jimbo]

Gary I am using my Decca with the standard plastic mounting. All other mountings ie Deccapod, GB clamp will change the sound. Can't tell you if for better or worse but I have had it on very good authority the plastic bracket works best as it takes out some of resonance of the tin can.

I run mine like this with blue tac and it sounds absolutely stunning.