Two magnificent SP10s landed in my greedy lap recently. They carry both the BBC and SABC labels (?) and appear to be in exceptional condition, properly maintained and 100% original.
I had to open the motor on one just to reassure myself that the reason for the rumble, vibration and inability to stabilise the speed was not of the mechanical nature. The motor/spindle/bush were as new. Re-lubed and reassembled.
I suspect the caps or cold solder joins on the drive/logic boards because the rumble/vibration and speed problems disappear completely after the TT standing powered for about 30 minutes. The platter doesn't even need to spin.
The other SP10 is perfect except for the strobe light that is sometimes on, sometimes off. Pesky 115V supply for the neon bulb and the bulb itself are apparently a regular problem. LED conversion, here we come... or not, we'll see.
So, having one SP10 that works, and itching like mad to finally hear why is this beast so much admired and respected, this weekend was the woodwork time. Took me half a day to clean up the table saw top and around it so that I can roll it into the driveway and start producing dust.
This post is about my plinth idea so lets get to it.
Long story short - I googled and googled... and didn't like nor understand the efforts gone into nearly all plinths I've seen. This TT was designed to be as quiet and rumble free as the Japanese design and engineering were able to execute in the 70s... so why the big and heavy plinths...? :thinking:
I did like "The mule"; light(ish) skeletal plinth that started it's life as a test plinth and became permanent. Which put some ideas in my head ...
So I started thinking ...
- I wanted a plinth that is as small as possible - not a "statement", but quite the opposite - practically invisible, something that would not distract from the industrial heart and the looks of the TT itself, something that will look as a part of the TT and not ... like a plinth?
- I was already set on being able to attach more than one tonearm to it - a state of the art TT deserves to be used as a workhorse and a reference TT that it was designed to be ...
- but then I thought - it MUST be a modular "system"! ... Ouch. OK, let's think this through...
- It must allow me to attach armboards as I need it or feel like it ...
- This must be very quick and easy; foolproof and perfectly repeatable every time - if you know what it takes to perfectly set up a TT, tonearm and cart, you'll know this is not a small ask ...
- all this means that the adjustment range of the armboard/arm must be practically infinite ...
- and I wanted to be able to swap the armboard/arms around, so a "system standard" for armboard attachment had to be devised ...
- Now, there are 3 perfectly usable sides on the SP10 for tonearm mounting, two that can cater for 9" and one (left) that can only cater for 10-11" or longer...
- So, a universal armboard "platform" that can be attached to any of the sides with the actual tonearm specific armboard being an easy-fit into the platform ... hmm ...
- As mentioned, I don't believe that enormous amount of damping is required, so small and simple should work fine ... I hope ...
- Finally, all these ideas needed to put to test, to eliminate the "I hope" part ...
- meaning that I would need to build a sacrificial - proof of concept - plinth first.
Plenty of MDF offcuts around, so the material choice was easy. BTW, my mitre saw with a brand new 70+ tooth aluminium/chipboard blade for the reasons unknown to me burns one side of the cut badly - and only one side, always!?
Now, I know this doesn't look like much but believe me, the concept under test already allows me to adjust all armboard angles using those 3 bolts on the side which at the same time are decoupling the armboard platform from the main plinth body using rubber grommets. If there are any specific tonearm installation requirements - for example, Rega arms with their notorious lack of VTA adjustment - no problem. Proof of concept has been accurately set and drilled for Rega, but just a small modification to it will allow for VTA adjustment. Current one-piece top board will be replaced in the final version with a hollowed platform that will just accept the tonearm specific top board (10mm should do... maybe 12... Alu-MDF or Alu-birchply composite... well, that's what the testing is all about).
There is no metal in the plinth except for those 3 bolts that clamp the armboard to the plinth... All done with Alcolin "Ultra" - awesome glue.
And that's all for now - as I said, baby steps.
And here's it is, at it's workplace :clap:
* Those black discs sitting on top of the start/stop button are a "workaround" for the so-called BBC mod until I find how to undo the mod so that the button "latches" as designed to either run or don't run.
First impressions:
This is one sonically scary combo - not even a perfect match of the tonearm and cartridge, but huh, it delivers shockingly good. A lot is different from the sonic memory of the previous setup which was briefly (after the WTL Versalex left the building :'(), a Technics SL10 ... which is no slouch in it's own right. But this... this is just too good to be true.
Everything is like on drugs - all happy singing dancing cheerful playful and immensely enjoyable. Quite unexpected. Resolution and imaging are mind blowing. Bass is slightly less pronounced than Versalex...
Granted, I have zero experience with this cartridge so ... there's plenty more testing work to do and lots and lots of music to listen to. :Whoohoo: :clap:
Some cartridge swapping is on the cards as well as trying a 12" arm and much lower compliance MC cartridge. Now that I have the bones of the modular armboard system, swapping things around should become dead easy. I'll need to make a mod to my adored "Dulcet" - add multiple RCA inputs and a 3 position toggle ...
Baby steps ...
I had to open the motor on one just to reassure myself that the reason for the rumble, vibration and inability to stabilise the speed was not of the mechanical nature. The motor/spindle/bush were as new. Re-lubed and reassembled.
I suspect the caps or cold solder joins on the drive/logic boards because the rumble/vibration and speed problems disappear completely after the TT standing powered for about 30 minutes. The platter doesn't even need to spin.
The other SP10 is perfect except for the strobe light that is sometimes on, sometimes off. Pesky 115V supply for the neon bulb and the bulb itself are apparently a regular problem. LED conversion, here we come... or not, we'll see.
So, having one SP10 that works, and itching like mad to finally hear why is this beast so much admired and respected, this weekend was the woodwork time. Took me half a day to clean up the table saw top and around it so that I can roll it into the driveway and start producing dust.
This post is about my plinth idea so lets get to it.
Long story short - I googled and googled... and didn't like nor understand the efforts gone into nearly all plinths I've seen. This TT was designed to be as quiet and rumble free as the Japanese design and engineering were able to execute in the 70s... so why the big and heavy plinths...? :thinking:
I did like "The mule"; light(ish) skeletal plinth that started it's life as a test plinth and became permanent. Which put some ideas in my head ...
So I started thinking ...
- I wanted a plinth that is as small as possible - not a "statement", but quite the opposite - practically invisible, something that would not distract from the industrial heart and the looks of the TT itself, something that will look as a part of the TT and not ... like a plinth?
- I was already set on being able to attach more than one tonearm to it - a state of the art TT deserves to be used as a workhorse and a reference TT that it was designed to be ...
- but then I thought - it MUST be a modular "system"! ... Ouch. OK, let's think this through...
- It must allow me to attach armboards as I need it or feel like it ...
- This must be very quick and easy; foolproof and perfectly repeatable every time - if you know what it takes to perfectly set up a TT, tonearm and cart, you'll know this is not a small ask ...
- all this means that the adjustment range of the armboard/arm must be practically infinite ...
- and I wanted to be able to swap the armboard/arms around, so a "system standard" for armboard attachment had to be devised ...
- Now, there are 3 perfectly usable sides on the SP10 for tonearm mounting, two that can cater for 9" and one (left) that can only cater for 10-11" or longer...
- So, a universal armboard "platform" that can be attached to any of the sides with the actual tonearm specific armboard being an easy-fit into the platform ... hmm ...
- As mentioned, I don't believe that enormous amount of damping is required, so small and simple should work fine ... I hope ...
- Finally, all these ideas needed to put to test, to eliminate the "I hope" part ...
- meaning that I would need to build a sacrificial - proof of concept - plinth first.
Plenty of MDF offcuts around, so the material choice was easy. BTW, my mitre saw with a brand new 70+ tooth aluminium/chipboard blade for the reasons unknown to me burns one side of the cut badly - and only one side, always!?
Now, I know this doesn't look like much but believe me, the concept under test already allows me to adjust all armboard angles using those 3 bolts on the side which at the same time are decoupling the armboard platform from the main plinth body using rubber grommets. If there are any specific tonearm installation requirements - for example, Rega arms with their notorious lack of VTA adjustment - no problem. Proof of concept has been accurately set and drilled for Rega, but just a small modification to it will allow for VTA adjustment. Current one-piece top board will be replaced in the final version with a hollowed platform that will just accept the tonearm specific top board (10mm should do... maybe 12... Alu-MDF or Alu-birchply composite... well, that's what the testing is all about).
There is no metal in the plinth except for those 3 bolts that clamp the armboard to the plinth... All done with Alcolin "Ultra" - awesome glue.
And that's all for now - as I said, baby steps.
And here's it is, at it's workplace :clap:
* Those black discs sitting on top of the start/stop button are a "workaround" for the so-called BBC mod until I find how to undo the mod so that the button "latches" as designed to either run or don't run.
First impressions:
This is one sonically scary combo - not even a perfect match of the tonearm and cartridge, but huh, it delivers shockingly good. A lot is different from the sonic memory of the previous setup which was briefly (after the WTL Versalex left the building :'(), a Technics SL10 ... which is no slouch in it's own right. But this... this is just too good to be true.
Everything is like on drugs - all happy singing dancing cheerful playful and immensely enjoyable. Quite unexpected. Resolution and imaging are mind blowing. Bass is slightly less pronounced than Versalex...
Granted, I have zero experience with this cartridge so ... there's plenty more testing work to do and lots and lots of music to listen to. :Whoohoo: :clap:
Some cartridge swapping is on the cards as well as trying a 12" arm and much lower compliance MC cartridge. Now that I have the bones of the modular armboard system, swapping things around should become dead easy. I'll need to make a mod to my adored "Dulcet" - add multiple RCA inputs and a 3 position toggle ...
Baby steps ...
