distortion on 45 rpm direct disk

by **afg** » 19 Jul 2004 08:50

Hi

I am new to the vinyl world and to this forum.

I have a NAD533 TT with the Rega 250 arm and the stock Goldring Elektra cartridge. The phono stage is a Nad PP2. Rest of the equipment is a Krell 300i amp and Dyn Audience 82 speakers.

I used to have inner groove distortions which I correct - to some extent - using the TT basics protractor. The distortion is yet present on some records particularly on female voices. I also adjusted the antiskate and VTF (1.7gms) using the HFN test record and the Shure force gauge.

A few days back my cousin lent me a Beethoven Piano Sonata which was a Japanese 45RPM direct disk pressing. The recording was awsome and dynamic. So dynamic that the sound distorted on heavy passages.

What could the reason be? Is my low-end cart not up to the mark? Or is there some other reason. Kindly help.

by **JaS** » 19 Jul 2004 12:04

Disregarding poor quality pressings, the standard Rega arm is a capable device and isn't prone to mistracking or distortion so I'd take a closer look at the cartridge and phono stage. The Elektra is a low budget cartridge and I'd imagine it would track more securely towards the top end of its recommended tracking force. You say you have the HFN test record, how does the cartridge fair with the anti-skate tracks? Also did you try a slightly higher tracking force? If the distortion is only on loud, heavy modulated passages have you tried borrowing a different phono stage? The PP2 is also a budget design and may be prone to clipping (although NAD claim it has greater overload margins than the earlier PP1). Also the NAD table has very little in the way of isolation from vibration so make sure its on a good stand or shelf well away from the speakers.

Finally yes I would question the use of a low budget cartridge and phono stage with an amplifier like your Krell, they where designed to be used in far less revealing systems and IME while you can get away with playing a £2000 deck through a £200 system, the reverse is rarely true. If you like the sound of the Goldring it might be worth upgrading to one of the 1000 series carts, although even here the extra cost of the 1012 and 1042 is easily heard over the entry level 1006, female vocals in particular sound much sweeter on the 1042. I wouldn't spend much more than this as the extra money would be better spent on a more capable deck, if you have enough vinyl to justify it :wink:

Regards,
JaS

by **afg** » 19 Jul 2004 12:49

JaS, thanks for the inputs. Really appreciate it as I have some Sheffiel Direct to Disk records which suffer the same problem on Piano solos.

The cartridge did fine till the 8th track of the anitskate test. I adjusted the bias till the buzzing was from both the speakers. The 9th track (torture test) failed though the cartridge did not jump out. However, all this was with the dust cover down. There was a lot of distortion on the 7th and 8th tracks with the dust cover up. The cartridge did indeed jump out on the 8th track with the dust cover up. Why was this?

I have placed the TT on my piano. Probably this is generating a lot of vibrations. Even the level is off, so I have put a lot of packing under the TT to get the correct level.

Do you think it is an alignment problem? Most of my other records play fine except for end-of-the track complex passages/female voices which yet distort mildly. But the piano distortion on heavy dynamic passages happens anywhere on the disk.

I will upgrade to a new cartridge once finances permit but for now I have to optimise my current setup.

Regards

Adil Gotla

by **JaS** » 19 Jul 2004 15:54

Hi Adil,
The 8th anti-skate test can be a problem for budget cartridges but a little extra VTF (max 2g on the Elektra) can help here. If it reduces tracking distortion on normal records you should get less wear too. Cartridge alignment could also be off but it only takes 2 minutes to check (you have a good protractor).

The NAD turntable lid acts as an antenna for airborn vibration and is best left in the closed position while playing or left off completely. I prefer to leave lids on as it helps reduce dust build up and means records don't need cleaning so often, others prefer them off.

Turntable stands are always a problem but especially for the unsprung NAD, and heavy wooden furniture is very bad as it stores up alot of energy. A piano sounds like the worst possible solution and this could well be the cause of your problem, on my Rega 3 I used to use a dedicated wall shelf (very cheap S/H) and it worked beautifully.

Just one more thought, I presume the stylus is OK?

Regards,
JaS

by **finkerbell** » 19 Jul 2004 15:55

I hesitated before posting this but...

When the sort of distortion you are describing is heard, the stylus is losing contact with the groove walls. This can result in damage to the groove since the stylus is bouncing around against the groove walls.

by **lanny** » 19 Jul 2004 15:59

The basic problem is most likely a cartridge with poor tracking ability. I would try increasing the VTF to 2 grams and remove the dustcover entirely when playing records. The cover probably isn't contributing to your mistracking, but it's a feedback antenna, especially when open.

Your PP2 will easily handle a low-output moving-coil cartridge. The AT OC9 is sweet, detailed, and tracks any LP I've ever played.

by **StephDale** » 19 Jul 2004 16:00

I suspect that if you're getting different tracking results with the cover up or down that the problem is due to static electricity.

If the deck becomes charged, which is always a problem with Rega derived decks as they've no seperate earth, then with the lid down the arm is operating in an electric field. My P25 was a b****r on a hot day if I was wearing long sleeved shirts; a quick swipe of a cuff over the lid and 'boing' up would come the arm... :shock:

As a result I always use my turntable with the covers removed completely.

The siting of the deck on a piano is not likely to be a huge problem in itself. Though turntables do like to be as well isolated as possible, have a search through this forum and you'll find plenty of ideas! Keeping it level (as you note) is very important too.

I'm not convinced that this is an alignment problem; though that's not a problem I've experienced either. I've heard that cartridge in both Rega P2 and Goldring GR1 decks and although it seems very bright and shiny I don't think it would mistrack like that if it was set up properly.

It's worth checking the arm for free movement at the end of its travel too. I'd run the cartridge over Seb's 'Rega-Baerwald Protractor' (from the library section) and see how well you're doing for alignment. And I agree with Jas about running it towards the top of it's tracking weight range.

Hope this helps :wink:

Steph

by **lanny** » 20 Jul 2004 00:49

Oh, one more thought: a dirty stylus is more prone to mistrack. Has yours been cleaned within the past 5 or 10 hours of play?

by **afg** » 20 Jul 2004 04:50

Hi Everybody

Thanks for your valuable inputs.

I am going to do the following (a lot of work but it will be fun):

1) Make a wall stand to isolate the TT.

2) Check the overhang/alignment once again.

3) Increase the VTF to 2 gms and

4) Order a new stylus if the above steps do not improve things. This TT was a demo piece so I am not sure of the condition of the stylus.

I have the RRL stylus cleaning liquid and brush. I brush the stylus after each side.

Thanks for the tips. Will keep you'll posted.

Regards

Adil

by **StephDale** » 20 Jul 2004 08:57

Adil,

Use less stylus cleaner....!!!

I clean mine about once a month or so. You'll need to leave it at least 1/2 hour after using before you can use the cartridge.

Why? Well the cleaning fluid wicks up the cantelever where it can damage the cartridge's suspension. If you use it while the fluid is still in the cartridge it can do pretty serious damage.

I suspect that changing the stylus and not cleaning as much will solve the problem :lol:

Steph