BSR P128R SC12M missing stylus

[Afriat40]

Hello all,

I am trying to put into use a BSR P128R turntable my family has since I was a small boy.
The pickup arm is still connected to a SC12M cartridge but is missing the stylus.

1. Is the SC-12M ideal for my BSR device?

2. Which stylus should be placed in my SC12M cartridge (some websites indicate ST12 and others ST17)?

3. where can i get the service manual (not the instruction manual) for my BSR P128R device ?

I attached a few pictures of my device.

Thank you all Adi

[john600601]

ST16 and ST17 are flipover, ST20 and ST21 are single LP/45 tip. But not ST12. Hope this helps!

[ben]

Is this deck incorporated into some kind of stereo system?

I mention it because, if you plan to use it with a modern-ish amp with 'phono' input, then you will need to change to a magnetic cartridge.

[Restoration73]

This is the steel platter version of the MP60, so a ceramic cartridge may be preferred.

[Afriat40]

Thanks Ben for you prompt reply.

you are correct, as I do intent to connect my BSR P128R device to a modern receiver - Harman AVR 142 to its CD input.
From what I understood, this connection does not require a preamp for my current ceramic cartridge.

however, any future magnetic cartridge will definitely require a preamp.

I appreciate your comment on that.

[hayerjoe]

Originally Posted by Restoration73

This is the steel platter version of the MP60, so a ceramic cartridge may be preferred.

I'm intrigued, why would the platter material impact the type of cartridge preferred?

[ben]

Originally Posted by Afriat40

Thanks Ben for you prompt reply.

you are correct, as I do intent to connect my BSR P128R device to a modern receiver - Harman AVR 142 to its CD input.
From what I understood, this connection does not require a preamp for my current ceramic cartridge.

Connected as you propose, you will find the sound weak and lacking in bass. This is because ceramic carts need equalization and a higher input impedance than these amps can provide.

[jamesperrett]

It might be worth reading through this thread if you haven't already done so

https://www.vintage-radio.net/forum/...d.php?t=183475

as it covers connecting a ceramic cartridge to a modern amp.

[mister valve]

Originally Posted by hayerjoe

I'm intrigued, why would the platter material impact the type of cartridge preferred?

Magnetic cartridges, as the name suggests, have a magnet fitted. So if a ferrous metal type turntable is fitted, it could exert a extra downward force on the cartridge.

Crystal & Ceramic cartridges would be unaffected by the turntable material.

[ben]

Originally Posted by mister valve

Magnetic cartridges, as the name suggests, have a magnet fitted. So if a ferrous metal type turntable is fitted, it could exert a extra downward force on the cartridge.

I've often seen this, but surely the tiny cartridge magnet, plus the fact there's a disc and a relatively thick rubber mat covering the platter suggest the effect would be negligible. Anyone have any more data or experience of this?

[Nickthedentist]

Some Goldrings have a chunky magnet above the stylus assembly, which surely must affect things in this respect.

[Restoration73]

Although turntables such as this with a 4-pole motor have a lower hum field, this can be
induced into the steel platter making hum worse, the problem is even more pronounced
with a basic 2 pole motor design, to the extent where a magnetic cartridge is unusable.

[Nuvistor]

The cartridge in post #1 looks damaged in the third photo, if it is there is no point getting a stylus.
The stylus fits between two ‘ears’, one looks broken, perhaps it’s just the photo, or my eyes.

[hayerjoe]

Originally Posted by Restoration73

Although turntables such as this with a 4-pole motor have a lower hum field, this can be
induced into the steel platter making hum worse, the problem is even more pronounced
with a basic 2 pole motor design, to the extent where a magnetic cartridge is unusable.

OK that's interesting, but why would a MM cartridge be impacted by hum OR is it that the hum is really caused by vibration and it's the vibration that's impacting the MM cart?

Chicken or egg? is the hum causing the vibrations at the cart via sound waves, or vibrations at the motor just impacting the cart (and incidentally causing a hum) ?!

and if vibration rather than soundwaves would it come more via the platter (which as Ben says has a rubber mat, a record, and is somewhat isolated from the deck via a rubber idler wheel) or the tonearm that's pretty much attached direct to the deck?

So many questions!

[Restoration73]

The hum is electrically and not mechanically induced.

Vibration in ac motors and transformers is predominantly 3rd harmonic - 150 Hz (for 50)

It is possible to read a record groove using a laser, indeed a Japanese model did. That
would have been immune to induced fields.

[crackle]

Originally Posted by hayerjoe

OK that's interesting, but why would a MM cartridge be impacted by hum OR is it that the hum is really caused by vibration and it's the vibration that's impacting the MM cart?

So many questions!

Surely any magnetic cartridge has a coil, and being a coil it is in effect a receiver for electro magnetic hum.
Mike

[mister valve]

Originally Posted by ben

I've often seen this, but surely the tiny cartridge magnet, plus the fact there's a disc and a relatively thick rubber mat covering the platter suggest the effect would be negligible. Anyone have any more data or experience of this?

Actually, now I think of it.... When I worked in a Factory making Record players back in the 1970's, one of their top range models was fitted with the "BSR P128R" deck and a Magnetic Cartridge.

I don't ever recall any problems with that combination. So maybe any so called problems with that combination, could be theoretical rather than in reality....

[Techman]

Originally Posted by mister valve

one of their top range models was fitted with the "BSR P128R" deck and a Magnetic Cartridge.

I don't ever recall any problems with that combination.

Perhaps it had an alloy platter and not a ferrous metal one.

[mister valve]

Originally Posted by Techman

Perhaps it had an alloy platter and not a ferrous metal one.

I believe the alloy platter version was the famous "MP60", and the version with a very heavy & deep alloy platter with a rotating centre spindle was the "HT70".

The P128R seems to have been a slightly cheaper version of the "MP60", with a lighter pressed steel platter fitted. Everything else about the deck was the same, although the P128R may have had a different motor fitted too? It's so long ago now (1970's), I can't remember for sure.

[Edward Huggins]

Your comments above as to the variants of this deck are correct. The HT70 will be very rare these days, whereas the cheaper P128 appeared in many "seperates" type systems and are much more commonly found.