The Bolt Mod

Posted by: trickytree on 15 November 2003

Have just fimished playing a few records after completing the bolt mod. If ever there was a mod/upgrade to the LP12 that could be recomended to everyone with the certainty that no-one will be disapointed, then this is it.

Surface noise is greatly reduced, and with that comes a wealth of low level information that was hidden without the 'bolt'. Dynamic range is increased with the benifit (to me) of being able to reduce the volume level. Notes stop and start faster, with obvious gains in PRaT.

All this is done with no perceived change in tonal balance. As I said at the begining, in my opinion there are no downsides to this mod. If you have a LP12, then just do it.

Paul.
Posted on: 17 November 2003 by Nime
quote:
Originally posted by Andrew L. Weekes:

No Linn PSU does this.

There is categorically no hunting involved with any Linn PSU, since they are not servo or PLL based as were the direct-drive TT's you are thinking of.

Andy


As a matter of fact (and strange as it may seem) I found I just couldn't tap my foot to a system with a Lingo'ed Linn. I tried three different Linns on three completely different systems over several hours with a wide range of music in three different locations. One Naim + Kans, one Naim + Tukans and one all Linn. The Lingo completely lost the rhythm for me. Hence my joke about "hunting". There's nothing worse than a lead foot! Thankfully the Valhalla is fine in that department. (Cue alternative opinions?) Smile

Nime

Everyone has the right to be wrong.
Posted on: 17 November 2003 by Andrew L. Weekes
quote:
(Cue alternative opinions?)


Oh, alright then Wink

My Lingo sounds great and was hugely better than the Valhalla it replaced, once I'd chopped out the nasty bit, that affected the Naim bits, rythmically Smile

The Exorcist

Andy.
Posted on: 17 November 2003 by JeremyB
P,

Thanks for posting the pic, it's quite impressive that we can read the label!

The next question: is there really a nut underneath the corner brace or is the stud in tension, pulling against the top plate?

Jeremy
Posted on: 18 November 2003 by P
J
Is there a nut under the brace? Good question. I've honestly no idea.

My guess is that there isn't but again I'll try and check the next time I'm underneath.

P
Posted on: 18 November 2003 by Nime
Originally posted by Patrick Dixon:

"There's something wrong with your foot?"


Which one? I only had three for testing Lingos and I've used them all up. Smile

Fortunately I made a full & speedy recovery the moment I heard my Valhalla'd Linn again. So there's nowt wrong with my (UK) size 10s thankyou.

It's true the Lingo darkens the background and bungs more information into the picture. Quite obviously so. It just doesn't have a clue about rhythm IMHO. If I had bought any of those three purely on reputation. I feel I would have had to take it back to the dealers. I should add that my Linn is an earlier model and the others were more modern.
In fact I may not even have corner braces on mine to do the "Bit of studding, some Araldite, a T-nut, and some plain hex nuts Mod." Wink

Nime

Everyone has the right to be wrong.
Posted on: 18 November 2003 by Chris Metcalfe
Does anyone
a) know if the latest lingo still affects Naim gear like the old one did
b) have a picture of the official LP12 upgrade on the latest decks?
Posted on: 18 November 2003 by JohanR
quote:
quote:
I'm not talking about a motor, you don't need one to drive a turntable, you just need to have a phase modulator, with inductive coupling to the platter. sort of a rotary transformer principal. I'm sure this has been done before by the way ...

To me that's a motor too - it's a linear motor applied to a circular track.


Patrick is of course right here.

If I remémber it correctly it was Fisher that used this kind of drive/motor in the late 1970-s, early 1980-s. A friend of mine had a Fisher turntable with remote control(!) in those days. Don't know if it used this type of drive or not, but it managed to sound considerable worse than the cheap Akai thing he used before.

And yes, one of the ideas with belt driven suspended designs is to filter out motor noice.

JohanR
Posted on: 18 November 2003 by MJSM
OK, I give up (does'nt hurt to think lateraly though).

Bye the bye, has anyone tried one of these

Mike
Posted on: 22 November 2003 by garyi
Well I did the mod!

I took lots of pictures, but none are great I will try and put a PDF together for anyone interested.

I was pleased to find a pre drilled hole on my brace, have no idea why but there you go. I used a 6mm bolt and some of that putty stuff for bonding metal, its done a great job, not particuarly attractive but does the job.

I also used some big washers as well.

Anyhoo, sound differences. Hard to state right now as I havn't tighnted the bolt too much yet.

There is more detail, this is for sure, but bass seems to have bloomed a little. I wonder if this is down to the fact the rack is resonably close to the firing speaker. it seems to me that thebolt will work both ways, removing some of the vibrations from the motor but also picking up vibrations from the room, what are peoples opinions on this/

I am not dissapointed with it, I think overall I prefer the sound with the bolt mod in, I will check it again tomorrow and tighten it some more.
Posted on: 22 November 2003 by Rico
Go to it, Garyi - another of your classik pdf's would be appreciated.

cheers!

Rico - SM/Mullet Audio
Posted on: 23 November 2003 by garyi
Here it is Rico, unfortunatly my mac is messing with me on PDFs right now, making them ten times bigger than the original so its in Word format:

http://homepage.ntlworld.com/gareth.irwin/theboltmod.doc
Posted on: 24 November 2003 by JeremyD
Re belt drive v direct drive:

I suspect that the main reason for Linn's choice of belt drive rather than direct drive was that it was much cheaper to implement. [E.g. I think the motor started life as an off-the-shelf model].

A suitable direct drive motor would probably have had to be custom designed and manufactured, which would have been very expensive.

--J
Posted on: 24 November 2003 by BigH47
As IT stated the direct drive motor is never at 33 1/3 rpm as it has a servo system and always "working" to keeps its speed.

Howard
Posted on: 24 November 2003 by Andrew L. Weekes
quote:
As IT stated the direct drive motor is never at 33 1/3 rpm as it has a servo system and always "working" to keeps its speed


Surely that's just a function of Direct Drive motors as implemented at the time.

I do think there is a disadvantage to DD though. The belt provides effective isolation across a wide bandwidth of an noise present within the motor assembly.

Even if one implemented a direct drive synchronous motor (to eliminate the PLL bandwidth issues) you now have the platter as a fundamental part of the motor and a whole load of vibration problems to deal with at the platter.

Not a recipe for good measurement of the vinyl groove, I'd suggest. I'd also agree with Jeremy's observation.

Andy.
Posted on: 24 November 2003 by Paul Ranson
Nobody seems to worry about the output of their Naim amps wobbling around the expected value as the feedback operates. I think there's no more reason to suppose that a properly implemented turntable with feedback will 'hunt'.

Much as I enjoy Ivor I think he doesn't have a good grasp of control engineering.

OTOH there's no real point in using a servo motor in a turntable when you can use a synchronous. The results rather speak for themselves...

Paul