Audio qualia

experience the real sound of music !

turntables for playing vinyl and shellac

For most of the 20th century, we have been able to listen to recorded music using a turntable to play vinyl or shellac records. It is thought by many audiophiles to be superior to any digitally derived format, and therefore it must be given serious consideration as a music source.

 

My vinyl days started in the 1960's with a Garrard A75, to be replaced by a Thorens TD150, a so-called 'suspended' design, eventually sporting a SME series ll tone arm, the 'best' of its day. That was decades ago, today I want to build something that will last my lifetime.

Most of today’s super decks use a belt drive system (so did the Thorens TD150) but this kind of design, if not properly engineered, can have problems with suspension and speed stability. And setting the speed can be difficult, not just for the set speeds, 33.3, 45 and 78 rpm, but anything in between!

There is a design, around for 50 years, that is available on ebay for little money that can, with suitable work, be made to provide excellent speed setting and stability, with superb sound reproduction if married to a good arm and pickup cartridge. I am talking about the Lenco range of turntables, made in Switzerland, and sold in the UK under the Goldring label, later to design their own transcription units to rival the best of the day, or any day!

 

So the GL75 was born, to be followed by their top of the range models, the G88 and finally G99, the latter two without arms. One improvement to be made is to replace the 1960's type plinth (basically a sprung wooden box) with something more appropriate. When used in such a modern plinth, the 'sound' of the deck is said to rival those decks costing several thousand pounds! No mean feat.

 

I bought a GL75 off eBay a couple years ago, and when I first used it, it was dreadful. Usual suspects, shot v block bearings in the tone arm, plastic idler and springy mounts. The v blocks were shot, and easily replaced. Sound was then reasonable with an Ortofon OM20 cartridge, but I could hear a mechanical noise through the speakers during quiet passages, between tracks and silent grooves. I tracked this down to the plastic idler wheel, the tyre was hard, and the bearing clicked. If fact, the hard tyre made it very difficult to engage speed, which needed a shift up the box to 78rpm, which then bumped it into life, and I could reset it to 33rpm. This needed changing, and at present I am using a metal two holer from another deck. The top plate is fixed (as it came) without using springs to a wooden plinth. It is now completely silent, electrically, electronically and mechanically, and I replaced the tyre on the plastic idler with an o ring, which is working just fine.

 
The sound was good, maybe 7 out of 10. I suspect the arm could be bettered (I have a Rega 250 and 300, and a Linn Basik+, and bits of SME's and the spike from a Hadcock), and the cartridge (Goldring 1040) came free with the Linn arm, but I have a good 1042, and swapping the styli does not show any degradation in sound quality from the 1040, so I assumed it was OK, and fitted it in the headshell.

When I bought the GL75 deck, it came with a G800 cartridge (banging around loose on the deck) and a polysealed bag of literature. I opened it the other day, and it contained some interesting stuff, including a Lenco set up protractor and overhang adjuster. It fits against the arm (you have to take off the lowering device) and over the spindle, of course. It had never been used. I thought I would recheck my overhang adjustment, it was way out (nearly half an inch/12.5 mm!) and moving the cartridge to the proper position increased the sound quality by another 0.5 points, maybe. A ceramic puck over the spindle has made no difference, however. 

One day I lost one channel on my deck, and I tracked it down to a dubious earth connection of a cartridge tag. I swapped to another headshell and voila, even better sound, I guess a nice 8.5/10, for a stock GL75/arm, in an old wooden plinth (no springs) and an old (but top quality) MM cartridge. It just gets better.

 

I lashed up a Rega RB250 arm pod (with a Goldring 1042 cartridge) using the bracket system I'm developing for a G99 build, next to my stock GL75. I'm sure the VTA and overhang needed playing with, but for a 'quick and dirty' look, it sounded very good, and had me reaching for a guitar/flute immediately, playing along to Jon Martyn's "Sweet little mystery", which I found appropriate. I gave the sound quality a 9/10, which meant the Lenco75 stock arm with the same cartridge sounds very good indeed by comparison (8.5/10). My bias, my opinion!

 

I found some other interconnect cables  and replaced the  4 metre run between the phono amplifier and the integrated amplifier. It made a little difference, maybe 0.1/10. Then I replaced the power cable ('kettle lead') which was from my guitar amplifier for the one supplied with the amplifier, again a 0.1/10 improvement. Re-checking the Rega250/Goldring1042,  I improved the geometry and maybe another 0.1/10, that makes 9.3/10 so far, but nowhere near to where I want to get.

I fired up a Goldring G99 that I bought recently, prior to modifying it with a bracket support system . Lowering the Goldring 1042/Rega250 onto Bert Jansch's 'Angie' (TRA 125) I was immediately aware of wow and flutter. Silly me had left the plastic idler wheel in place. I replaced it with a five holer, same w&f . I swapped this idler with the one from my superb stock GL75 (the silent one), still w&f, swapped the platter, still w&f .  Something must have been rubbing or the motor needed attention. I left the deck running at +78rpm for a while, then, if that failed  to bring relief, I would have had to change the motor.

I  took out the main bearing and greased it with Molybdenum Lithium grease, then reassembled it , it was quieter, but still the w&f was apparent. I refitted the 5 hole idler wheel and fiddled with it whilst playing. Suddenly, the slight pinging sound (mechanical, not through the speakers) disappeared along with the w&f, I didn't know exactly what I did, but I was happy. Re-aligned the cartridge in the headshell slightly, which made quite a difference.

I turned on the G99 and all seemed well (still very quiet, if not as quiet as the stock GL75 'The silent one' (TSO), even though it  was using 'TSO's idler and platter/mat). I played a few records, but wasn't that impressed with the sound, maybe 7/10 !

I decided to change the idler for the original (to this deck) 5 holer. I checked the playing weight (adjusted from 1.67g to 1.74g), adjusted height, overhang and skewness in headshell. A little better. I saw that the cartridge body (and therefore, presumeably the stylus) was a little lop-sided. Checked level of deck and arm, all seemed OK. Puzzled. I decided to put an acrylic base plate/sorbothane domes under the G99 (which was only suspended on three polyurethane lumps and 'Oasis foam' discs at the time. The acrylic base had a bubble level in it, so I made sure the base was level. I checked the level of the top plate near to the bearing whilst the platter was off. Level, good. Then I re-assembled the deck, and replaced the original platter/mat. Turned on the deck, there was a hum, damn, but I traced it to one of the supports touching the motor, a slight readjustment, and all was well. Checked the level of the top plate near to the speed changer, it was out (I had used this position to level the deck before !). Re-checked arm, it was level. Lowered cartridge onto a record, and it looked parallel, excellent. I am now playing an MJQ LP, and my feet are tapping, wonderful sound, 9.5/10.

 

I was going to do an assessment of noise levels from the motor as detected by a stylus resting on the top plate of the G99 lash-up. With the aid of an oscilloscope, I noticed a periodic increase in the signal, once per revolution, at the same point every time. Even with the motor turned off, I could 'see' the bump on the trace, until the platter stopped turning.

I suspected the bearing, so I removed it, and did a bit of polishing of the cup where the ball sits. I then re-greased the bearing, and re-assembled it. As I screwed in the small grub screw on the side of the bearing housing, I noticed that it was possible to tighten it too much, so that the end of the screw could scrape the bearing spindle. Could this be the source of my problem? Re-fitting the bearing, and setting up the Rega arm for playing records, I lowered the stylus onto the record (a Decca recording of highlights from Billy Budd, conducted by Britten himself, with P Pears and J Shirley-Quirk, P Tear, Ben Luxon, SET 452). The first few bars were a revelation, being very close to my Leak troughline tuner I had been listening to all day. Sound a very good 10/10; and this before I build it properly, and without damping (I could see the motor vibrations very easily, but if the slight bearing problem could cause so much difference, what could a fully fettled deck do?) And this was with a 1040 stylus, not my better 1042.

 

I though it might help (me) if I documented the improvements to my  system:
[The points out of ten are very arbitrary, but they are there to give some kind of idea of what kind of improvement I experienced.]

Basic system: 
score
7/10    (interpreted as good, but could be better)
Speakers:                      Epos M5 augmented with Foster ribbon tweeters
Amplifier :                      Cambridge Audio 640A MkII
Phono Preamplifier:       Cambridge Audio 640P
Record deck:                  Lenco GL75 in stock wooden plinth, stock L75 arm, Goldring 1040 cartridge,               


7.5/10   (adjusted overhang (out by half an inch)
8.5/10   (changed headshell for one with a better earth wire on the cartridge)
9/10      (changed the arm for a stock Rega 250 and Goldring 1042 cartridge)
9.1/10   (changed interconnect between preamp and amplifier)      
9.2/10   (changed old mains lead to original which came with amplifier)
9.3/10   (changed tracking geometry of RB250 slightly)
7/10      (changed deck for a G99 , loose brackets, with Rega250 arm and 1042 cartridge)
9.5/10   (lubricated main bearing)
10/10    (re-lubricated bearing and adjusted bearing screw so that it didn't scrub on the spindle)
12/10    (bolted on three brackets to G99’s top plate pan; all bolts M8)
13/10    (bolted two brackets to the acrylic base)
15/10    (replaced the stock Rega250 stub and counterweight with a DUO-Phonic stub and RB300 counterweight)
18/10    (bolted down deck to base plate including 3 brackets and four corner studs, and bolted arm pod to base plate (only one of three bolted down, took nearly 30 mins to get final arm alignment correct, hopefully, @ 223mm)

 

All three bolts of the arm pod are bolted down, and a wooden slat placed between the arm plate (aluminium) and its support (steel brackets). The sound has changed a little, its taken the slightly metallic sound of the Lenco away, something I find interesting to start with, but ultimately has too much of a sonic signature.

So I give the G99    19/10 so far!

 

I have to complete this deck by making and installing all the slats for the bries soleil, and test for vibrations, and add damping, where appropriate, although the slats, being held in place by nuts and bolts and washers is good at damping too. This is my record deck, it needs a respray, and other things to complete.

 

 

new blog

Sorry for these problems

The powers that overlord this website have threatened to deactivate this site for being too popular, without them getting their pound of flesh. Over the last several weeks they have withdrawn the stats counter, so that I cannot monitor the bandwidth, which is now over their specified limit. They have now stopped any change to any pages except this side panel.

So I have had to set up a new forum so that I can continue to help the hifi community. The new forum will be here:

http://

audioqualia.prophpbb.com

All the pages on this site, and many more, to found on the new site.

Hope to 'see' you all on the new forum, opening soon. Dated 21 Sept 2012


the second audio qualia site continues, here:

http://audioqualia2.webs.com/apps/blog/


script change history

there have been problems with the editor for webs.com, which has resulted in no new material being able to be added. So this site will remain open until the problem is fixed, but another site will be constructed to host a more practically based one. Hope to see you there, details as soon as I have found a stable platform (sounds like hifi!) kindest regards   Cats.


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