World-Designs-Forum  

Go Back   World-Designs-Forum > DIY Projects > Sources
Register FAQ Members List Calendar Gallery Today's Posts Search Today's Posts Mark Forums Read

Sources Your DIY source designs (turntables etc.)

Reply
 
Thread Tools Display Modes
  #1  
Old 5th September 2006, 01:38 PM
Rupert Rupert is offline
Member
 
Join Date: Jan 2006
Location: Whitstable, Kent, UK
Posts: 63
Default Garrard 401, eighteenth months on

A few of my thoughts, to anyone interested, on some of the things I've done to my Garrard 401 over the last 18 months. Nothing particularly clever, or even original, most of the ideas have been picked up from others elsewhere, but they are observations nonetheless. Preceding any of this was of course plenty of stripping down, cleaning, oiling and greasing, essential if your deck is old and hasn't been serviced for years. Things will have dried out for sure, those motor bearings for example, but I won't labour over this here.


The Martin Bastin bearing mod: This was my second mod, after the birch ply plinth, which I will get to later. You probably know this, but he fits an accurately centred tungsten ball bearing to the bottom of the spindle and installs a new thrust plate. The changes are reversible if you want to go back to what you had. He also cleans the bearing ultrasonically and lubricates with his own formula lubricant (he calls it a greasy oil). He also cleaned and centred my idler wheel at the same time, all for a very modest price. I don't think this is work you would want to try yourself. I thought overall the revamped bearing was an improvement, not an overwhelming change, but certainly adding some refinement and better resolution to proceedings. There was though a sense that something had been lost, some of the weight, impact and sheer brutishness I had liked was gone; the beast had been tamed a little, but overall a change for the better. Martin acknowledged this with a simple analogy "instead of being hit in the face with a block of concrete, it now feels like you are being hit by sand, cement and ballast", which I thought summed it up nicely. I've not messed with his work yet, so what is down to his lubricant and how much the bearing mod I don't know. I may try some different oil at some point, perhaps even grease.

The wiring loom: This was the next mod. For some reason the junction box, which handles just about all the wiring within the deck, is bolted to the motor. Most of the wires that go to it have no need to be anywhere near the motor. The wires are really stiff, something I didn't really appreciate until I started cutting them. The motor should move freely in its sprung suspension, but many have commented that the loom interferes somewhat with its freedom. Unbundling and separating out the wires is often suggested, to reduce the stiffness. I tried Martin's take on this problem, that goes one step further, by fitting a new connection block, mounted on a bracket, beneath the speed change mechanism, but there are plenty of ways you could achieve the same. Most all the wires were re-routed to the new connector, leaving only those that have to go to the motor (its power supply, earth etc) behind. These remaining wires were replaced with thinner flexible silicon insulated wire. I was surprised at the time how noticeable the improvement was, I wasn't expecting to hear any difference, but the treble in particular seemed sweeter and better resolved. Someone else please try this, I worry its just my imagination. If you do though, note that some of the neon strobes are 240V, fed directly from the mains, others are 120V wired across one half of the motor windings. Mine was 120V and was very bright when wired up with to 240V!. Fortunately I noticed before it blew.

Stiffening the bearing mount: Can't quite remember when I tried this, but I decided to make the bearing more ridged with respect to the chassis. I noticed that some of what I thought was play in my bearing, when trying to rock the platter, was actually flexing of the chassis/bearing mounting. I fitted two struts made out of small box section steel, to the base of the bearing. There is plenty of spare thread on the bolts that hold the end plate of the bearing in place, to slip in the lugs I formed on the ends of the struts. The struts run, at roughly right angles to each other, back up to the underside of the chassis. One was bolted in place to an existing hole. I had to drill second hole for the other. The mod again seemed to tighten up the sound a little, if only very slightly.
Attached Images
File Type: jpg Garrard1.jpg (81.7 KB, 122 views)
File Type: jpg Garrard3.jpg (80.1 KB, 117 views)
Reply With Quote
  #2  
Old 5th September 2006, 01:41 PM
Rupert Rupert is offline
Member
 
Join Date: Jan 2006
Location: Whitstable, Kent, UK
Posts: 63
Default Re: Garrard 401, eighteenth months on

Oops, a second page, good grief, uncle Peter will not be pleased!

The plinth: Nothing very original here, six sheets of 18mm birch ply with just enough cut out to accommodate the mechanism. Rather than gluing the whole lot together I experimented by bolting varying numbers of sheets together, so I could vary the mass and see what I preferred. Bolts are not great, as they provide vibration with a good shortcut through those nice layers of ply, but not so bad I hope, so as to negate the experiment. Out of interest I experimented without any bolts, allowing the sheer weight of everything to hold itself together. Seemed to work just as well, just don't try moving the deck around like this. As with others, mostly notably Mr Noble and Lorricraft, I found I preferred the lightweight plinth (just two layers of ply) and have now glued these together. These sit on four metal spacers (washers), laid atop the four remaining layers of ply, which I have also now glued together to form a base, a small air gap remaining between the two. I've tried various materials/objects (i.e. decoupling) between the plinth and base (rubber, cork, sorbothean, bubble wrap, spikes you name it) and have stuck with the metal washers. Hard seems best. Hard metal spikes also seem to work best as feet beneath the deck too (not tried ball bearings yet). Introducing soft/squishy and more compliant material here or between the plinth/base softens and defocuses the sound to varying degrees. This is not necessarily bad, and could be an ingredient you wish to introduce. Of course my preferences could be influenced by the support my deck sits on, which is a heavy rack with 12mm glass shelves standing on a concrete floor. I'm not trying to stop vibration from a bouncy wooden floor running up into the turntable. The turntable itself is bolted directly to the plinth, seems better like this, the original rubber washers and circlips having been removed (take care without the circlips, as there is nothing to prevent you over tightening the bolts in the chassis and cracking it or popping off the chrome facia).

Can't explain why I prefer the light plinth. In many respects the heavy plinth sounds "better", tighter and more controlled, certainly in the bass, but it sounds rather lifeless in comparison, the sound somewhat concentrated in the mid, the treble rather subdued and the bass less exuberant. I would like to believe the argument I've often seen that light plinths store less vibrational energy etc, and sound better for this reason. This may be true, but I can't help thinking the thin plinth also adds something that is not actually on the record. Resonance that sounds pleasing, and thereby a colouration and distortion of the tonal balance of the deck, that one likes the sound of. One only has to tap the light plinth when a record is playing to hear just how resonant and alive it is.

I improved things further by creating a separate armboard, detached from the plinth. I know others have tried decoupling armboards. My solution was to support the armboard on four short metal studs screwed into the base (at the moment the armboard is cut from mdf, I will try other materials sometime). Oversized holes are drilled into the plinth to allow the studs to pass up through the plinth without touching it. The armboard is then bolted onto these studs, sitting on spacers then metal washers and lastly rubber washers. In this way the arm board is supported by the high mass of the bass, not the lighter more resonant mass of the plinth. The amount of torque applied to the bolts affects the sound, and indeed removing or replacing the rubber washers with other materials. Finger tight seems best. I have wondered if the perceived benefits of high mass plinths (they are, as we know, commonly cited as a means of eliminating the dreaded rumble of idler wheels) have rather more to do with the way they support the arm, not the turntable.

I do wonder how this the two layer ply plinth can possibly eliminate rumble by sinking or absorbing the energy, as is suggested. It weighs little in comparison to the heavy mass of the turntable itself, yet it seems to work well, with little rumble that I can hear (ok so I've not gone looking for it). If anything its something of a sounding board, one that is likely picking up vibration from the loudspeakers, and feeding it back into the system (funny how rarely acoustic feedback from loudspeakers is mentioned when discussing all those vibrations in turntables). With this in mind I have been playing with the idea of no plinth at all, but that’s for another day.

I have of course tried endless combinations of DIY mats, but the old rubber mat is pretty good, a nice dense and solid sound with bass, but improved I think with something thin beneath to provide some decoupling from the platter. Presently I am enjoying the funk mat. I could go on, but have rambled enough.

Rupert
Attached Images
File Type: jpg Garrard2.jpg (65.2 KB, 96 views)
Reply With Quote
  #3  
Old 5th September 2006, 03:06 PM
pre65's Avatar
pre65 pre65 is offline
Senior Member
 
Join Date: Jan 2006
Location: Ashen- Essex/Suffolk bord
Posts: 4,370
Default Re: Garrard 401, eighteenth months on

Hi Rupert-a well put together article.

i particularly like the way you have decoupled the armboard,i am now going to use a variation on your theme for mine.

Philip
__________________
Philip.

Everything in this post is my honest opinion based on what i thought I knew at that very moment in time.
Reply With Quote
  #4  
Old 5th September 2006, 03:49 PM
Cobblers's Avatar
Cobblers Cobblers is offline
Senior Member
 
Join Date: Jun 2006
Location: Malvern
Posts: 1,225
Default Re: Garrard 401, eighteenth months on

Rupert,
Good stuff,
It looks like given us a comprehensive review of your findings.

Clearly lots to do!

Iv'e only been playing at this tuning/plinth building for a couple of weeks or so after work and a bit of holiday time.
You've probably read that i've built mine as a skeletal plinth.

Cleaning the ldler wheel gives a massive improvement, at least it did with mine, which was clearly uneven from dirt/grease.

I will look into decoupling these cables, as you have.

I'm using the light plinth method, 2 layers of el cheapo MDF sandwiched glued by evo stick.

Granite base.
When I got rid of the the rubber squash balls (essential with mdf base and MDf shelf support to reduce rumble) I found the great treble I had 1st heard before (albeit initially plus hum, rumble and far less dynamics) come back with avengence without the heinous hum rumble etc, along with even stronger tighter Bass. I do not have anything decoupling the plinth from pine supports currently.

The Granite support (ok, Granite chopping board!) I have found to be win win situation over the 25mm MDF support shelf.

Last edited by Cobblers; 5th September 2006 at 04:39 PM.
Reply With Quote
  #5  
Old 5th September 2006, 08:13 PM
Rupert Rupert is offline
Member
 
Join Date: Jan 2006
Location: Whitstable, Kent, UK
Posts: 63
Default Re: Garrard 401, eighteenth months on

Yes lots of things you can try and lots of fun to be had and so many different approaches. I think you really must experiment for yourself, and leave as many options open as possible, because what works for one person in their system is not necessarily going to be right for you, a rather obvious and often made statement I know, but true.

Once you have got it basically set up ok, a lot of changes seem merely to adjust the balance in some way, and are neither right or wrong. It often seems difficult to make it sound bad, just different, and sometimes difficult to decide what you prefer. Also what sounded best with my hifi ears on wasn't always what I ultimately enjoyed listenening to the most.

I forgot to mention the old light bulb trick. For those would haven't stumbled on this one, simply connect a 40W or 60W light bulb in series with the power supply to the motor. This will reduce the voltage supplied to the motor, therefore reducing its speed, allowing one to turn down the amount of eddy braking applied. There are of course more elegant ways of reducing the voltage but this is cheap and cheerful. With the voltage reduced, the presentation seemed smoother and more refined, but had lost some of the punch and grip I liked, so I abandoned this one, but it might suit you.

Also, for some reason, I decided to have a look inside the mains switch recently. A couple of springy metal contacts lie inside the brown plastic box with some caps (and I think resistors) on each for spark suppression. If you think your switch is ok, leave it alone, because its one of those things that’s a sod to reassemble. In fact I haven't. I was surprised, as the deck operated ok, to find the contacts in mine absolutely black and filthy, and the thick brass base plate of one switch fatigued (by constant flexing) to the point where it fell apart in my hands with virtually no effort when I took it out. I don't expect the condition of my switch is unique. Quite how it was conducting electricity I don't know. I've bypassed the switch for now, until a replacement is found, and just turn the deck on at the wall. Might be my imagination but it seems to sound better without the dirty contacts and dodgy switch.

I am of course following everyone else's exploits with interest, but must give my PhonoII some attention.

Rupert
Reply With Quote
  #6  
Old 5th September 2006, 09:00 PM
Greg.'s Avatar
Greg. Greg. is offline
Senior Member
 
Join Date: Dec 2005
Location: Bristol, UK
Posts: 3,087
Default Re: Garrard 401, eighteenth months on

Hi Rupert,

Great posts which is of great interest for other 401 owners. You've exposed some tweaks I've not previously read about and your own conclusions from your personal research will be invaluable to others.

Really good stuff and I've picked up several tips as I start on my own 401 'reference' TT. Thank-you.

Best wishes,

Greg
Reply With Quote
  #7  
Old 5th September 2006, 09:45 PM
Clive Clive is offline
Senior Member
 
Join Date: Dec 2005
Location: Alrincham, Cheshire, UK
Posts: 788
Default Re: Garrard 401, eighteenth months on

Great stuff! I suggest you think about the replacing the suppressor too, it'll be younger than the one on my 301 but if it leaks I suspect it creates a phase error and muddies the sound.
Reply With Quote
  #8  
Old 5th September 2006, 10:24 PM
Cobblers's Avatar
Cobblers Cobblers is offline
Senior Member
 
Join Date: Jun 2006
Location: Malvern
Posts: 1,225
Default Re: Garrard 401, eighteenth months on

Quote:
Originally Posted by Rupert
Once you have got it basically set up ok, a lot of changes seem merely to adjust the balance in some way, and are neither right or wrong. It often seems difficult to make it sound bad, just different, and sometimes difficult to decide what you prefer. Also what sounded best with my hifi ears on wasn't always what I ultimately enjoyed listenening to the most.


Rupert
I doubt i'm into fine tuning stage yet, early days. I still have a minor hum (only with needle on record, mainly audible only on quiet patches slightly more so than the Rega and a lot more so than the LP12), though I think most wouldn't worry about it, it bugs me know.

The table is near an alcove, near a TV and close to a valve amp so plenty of possibilities other than blaming the deck itself. Perhaps with all that it shouldn't sound as flippin' good as it does.
Though it is probably something in the deck. I haven't looked at servicing the motor yet.

The excellent treble and punchy Bass seems to be real highlights with this Garrard 401. I don't get the idea that it suffers in the treble, I haven't heard the 1042 sound so open and clean.
Reply With Quote
  #9  
Old 5th September 2006, 10:41 PM
Rupert Rupert is offline
Member
 
Join Date: Jan 2006
Location: Whitstable, Kent, UK
Posts: 63
Default Re: Garrard 401, eighteenth months on

Hum? Is the chassis of your deck earthed to your phono? I had hum when I changed over to the Hadcock arm, only became audible when I brought the arm over to the record, and got a little louder as it neared the centre. This never happened with the SME 3012, but if I remember correctly the deck was earthed through the SME cable/connector. I fixed a piece of wire somewhere to some exposed metal on the chassis and connected the other end to the earth post on my phono and the hum vanished. This might be the cause of your hum?

Clive, by the suppressor, you mean the switch contact suppressor? If and when I get another on/off switch fitted, I will replace them. There are two, as it is a double pole switch. RS 210-370 or Maplin RG 22Y seem right, but are to big to fit in the old box.

Rupert
Reply With Quote
  #10  
Old 5th September 2006, 10:49 PM
Clive Clive is offline
Senior Member
 
Join Date: Dec 2005
Location: Alrincham, Cheshire, UK
Posts: 788
Default Re: Garrard 401, eighteenth months on

Yes the switch contact suppressor. When I came to order the RS part I found it was discountinued, even though it's in the catalogue:

http://www.world-designs.co.uk/forum...ead.php?t=1432
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Garrard 401 advice Cycleallday General 16 3rd September 2006 05:25 PM
Garrard 401 mat david counter WAD General 1 9th May 2006 11:57 AM
garrard cartridge slide PhilN General 2 28th January 2006 04:01 PM
Garrard 401 Driver - Trouble IslandPink Sources 16 24th January 2006 05:26 PM


All times are GMT +1. The time now is 11:17 AM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright World Designs