Garrard SP25 MK IV anti-skating problem - UK Vintage Radio Repair and Restoration Discussion Forum

sonique · 18th Jan 2023, 10:09 pm

Hello everyone!

My first post here, I hope to find a solution to the problem.

Turntable is Garrard SP25 MK IV, cartridge is Shure M75-6S. Tracking force is set to 2gr and anti skating also according to the instructions to value 2. The turntable is leveled. With these settings, the sound is good, but I also noticed certain distortions, so I decided to check the anti-skating.

I checked with a blank vinyl record and noticed that regardless of whether the set value is 0 or 5, the tonearm slides towards the center of the record at the same speed. Stylus is in working order, no tip missing or damaged. The impression is as if the spring does not exert any force on the tonearm. Maybe I'm wrong, this is new for me.

The pictures show the position of the spring for values 0, 2 and 5. You can also see that the other end of the spring is attached to the tonearm. When the anti skating is in position 5 it is possible to see the movement of the spring in accordance with the movement of the tonearm.

The spring also reacts when the anti-skating lever is moved.

I haven't dared to disassemble this device on my record player, maybe more instructions would encourage me to do so. I don't even know if I need to do that.

Is there a possibility that the spring has weakened or maybe it is not well positioned in the case itself? I have no experience and all your comments and suggestions are welcome.

Thank you so much in advance for any assistance!

jamesperrett · 18th Jan 2023, 11:55 pm

I think 2g tracking force is a bit light for the M75-6S, especially if you aren't using a Shure stylus. You may have more luck using it at 2.5-3g.

sonique · 19th Jan 2023, 12:13 am

Thanks for your reply. The stylus is a Shure M75-6, there are no changes when the tracking force is increased to 3gr, it still behaves the same.

Chiltern · 19th Jan 2023, 5:42 pm

Here are a couple of pic of a rather dusty SP25 hybrid in my workshop, based on a MkIII but with a MkII arm and diecast platter. It does however have the same anti skate mechanism as a MkIV.

The arm is sitting stable on the plain section of a Decca test record, pw just over 3g and using a shure M75-6.

I can only asume that the OP's anti skate is mis aligned or the spring has weakened over the last 50 years. More investigation needed.

Alan

TIMTAPE · 19th Jan 2023, 7:50 pm

No familiarity with that model but I suspect the answer will be found underneath, not from the top.

ajgriff · 19th Jan 2023, 8:12 pm

The anti-skating arrangement on most decks is very rudimentary and is only an approximation anyway. A better way to optimise the setting (and tracking force) is to use a good quality test record. For example the Hi-Fi News Analogue Test LP has tracks which allow you to set anti-skate force for minimum distortion using a given tracking force. Unfortunately the price of the LP has rocketed in the last couple of years due to the vinyl revival although it's still possible to pick up used examples for reasonable money. The only downside is that the record may well highlight the deficiencies in your existing equipment which may send you off down upgrade alley!

Alan

sonique · 20th Jan 2023, 12:59 am

Thanks to everyone for the advice and suggestions. I checked the mechanics under the tonearm, I didn't find any obvious problem or obstruction. All parts are clean and lubricated.

What I'm trying to do now is determine if the anti-skating is working properly or not.

Unfortunately I don't have a test LP so I have to rely on other methods. I tested the anti-skating when the tonearm is level and in a horizontal position and the tracking force is set to 0.
The tonearm reacts as it should, when the anti-skating is set to 0 there is no movement and from 2 to 5 it moves towards the arm rest.

However, when I do a test with a blank LP, the only time the movement of the tonearm towards the center slows down a bit is when the tracking force is less than 2 and the anti-skating is 5.

Is there anything else that can be done, tested, checked?

18th Jan 2023, 10:09 pm	#1
sonique Diode Join Date: Jan 2023 Location: Zrenjanin, Serbia. Posts: 3	Garrard SP25 MK IV anti-skating problem Hello everyone! My first post here, I hope to find a solution to the problem. Turntable is Garrard SP25 MK IV, cartridge is Shure M75-6S. Tracking force is set to 2gr and anti skating also according to the instructions to value 2. The turntable is leveled. With these settings, the sound is good, but I also noticed certain distortions, so I decided to check the anti-skating. I checked with a blank vinyl record and noticed that regardless of whether the set value is 0 or 5, the tonearm slides towards the center of the record at the same speed. Stylus is in working order, no tip missing or damaged. The impression is as if the spring does not exert any force on the tonearm. Maybe I'm wrong, this is new for me. The pictures show the position of the spring for values 0, 2 and 5. You can also see that the other end of the spring is attached to the tonearm. When the anti skating is in position 5 it is possible to see the movement of the spring in accordance with the movement of the tonearm. The spring also reacts when the anti-skating lever is moved. I haven't dared to disassemble this device on my record player, maybe more instructions would encourage me to do so. I don't even know if I need to do that. Is there a possibility that the spring has weakened or maybe it is not well positioned in the case itself? I have no experience and all your comments and suggestions are welcome. Thank you so much in advance for any assistance! Attached Thumbnails

18th Jan 2023, 11:55 pm	#2
jamesperrett Octode Join Date: May 2007 Location: Liss, Hampshire, UK. Posts: 1,876	Re: Garrard SP25 MK IV anti-skating problem I think 2g tracking force is a bit light for the M75-6S, especially if you aren't using a Shure stylus. You may have more luck using it at 2.5-3g.

19th Jan 2023, 12:13 am	#3
sonique Diode Join Date: Jan 2023 Location: Zrenjanin, Serbia. Posts: 3	Re: Garrard SP25 MK IV anti-skating problem Thanks for your reply. The stylus is a Shure M75-6, there are no changes when the tracking force is increased to 3gr, it still behaves the same.

19th Jan 2023, 5:42 pm	#4
Chiltern Heptode Join Date: Dec 2008 Location: Somerset, UK. Posts: 555	Re: Garrard SP25 MK IV anti-skating problem Here are a couple of pic of a rather dusty SP25 hybrid in my workshop, based on a MkIII but with a MkII arm and diecast platter. It does however have the same anti skate mechanism as a MkIV. The arm is sitting stable on the plain section of a Decca test record, pw just over 3g and using a shure M75-6. I can only asume that the OP's anti skate is mis aligned or the spring has weakened over the last 50 years. More investigation needed. Alan Attached Thumbnails

19th Jan 2023, 7:50 pm	#5
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,971	Re: Garrard SP25 MK IV anti-skating problem No familiarity with that model but I suspect the answer will be found underneath, not from the top.

19th Jan 2023, 8:12 pm	#6
ajgriff Nonode Join Date: May 2004 Location: Halifax, West Yorkshire, UK. Posts: 2,587	Re: Garrard SP25 MK IV anti-skating problem The anti-skating arrangement on most decks is very rudimentary and is only an approximation anyway. A better way to optimise the setting (and tracking force) is to use a good quality test record. For example the Hi-Fi News Analogue Test LP has tracks which allow you to set anti-skate force for minimum distortion using a given tracking force. Unfortunately the price of the LP has rocketed in the last couple of years due to the vinyl revival although it's still possible to pick up used examples for reasonable money. The only downside is that the record may well highlight the deficiencies in your existing equipment which may send you off down upgrade alley! Alan

20th Jan 2023, 12:59 am	#7
sonique Diode Join Date: Jan 2023 Location: Zrenjanin, Serbia. Posts: 3	Re: Garrard SP25 MK IV anti-skating problem Thanks to everyone for the advice and suggestions. I checked the mechanics under the tonearm, I didn't find any obvious problem or obstruction. All parts are clean and lubricated. What I'm trying to do now is determine if the anti-skating is working properly or not. Unfortunately I don't have a test LP so I have to rely on other methods. I tested the anti-skating when the tonearm is level and in a horizontal position and the tracking force is set to 0. The tonearm reacts as it should, when the anti-skating is set to 0 there is no movement and from 2 to 5 it moves towards the arm rest. However, when I do a test with a blank LP, the only time the movement of the tonearm towards the center slows down a bit is when the tracking force is less than 2 and the anti-skating is 5. Is there anything else that can be done, tested, checked?