Technics 1210 internal regulation mods

[MCRU]

What does one do when one doesn't have the time or space or CBA doing all this internal jiggery pokery, any volunteers to do it for me for a nominal fee?

Unless there is an idiots guide to the whole thing, that would sell well???

[Puffin]

Bit worrying of you're making mains cables isn't it

[MCRU]

Bit worrying of you're making mains cables isn't it

Not really mate because I very rarely solder mains cables as solder worsens mains lead performance IMHO, I was referring to what looks like delicate solder work and accidentally ruining the whole thing, that was what I was worried about.

Merry Christmas BTW.

[Puffin]

I was only pulling your leg (or cracker)

Regards

Rob.

[leo]

Just added a few updates

[MCRU]

Just added a few updates

WHERE?

[leo]

Rather than add later in the thread I'll keep adding onto the first post on the first page saves faffing about trying to find things

[UV101]

OK! 1st steps taken last night and now I have an external DC supply!

I have built an unregulated 30v supply. 30va 2x9v (series connected) which give about 30v DC when rectified. That should deliver up to about 1.6A on the output when needed. MBR16100 16A schottky's provide rectification and 2 Panasonic 10,000uF 35v (low esr) provide the smoothing.

I removed the mains transformer and board from inside the player and used the existing heatsink mounting to attach my own FET based regulator carefully set to 21v.

As this is the 1st time i've taken a look inside, I looked to see what else could be changed and I've changed a few rail caps for Rubycon ZA's as I know they are good quality low esr caps.

When I've built another reg, i'll definitely be looking to seperate the control side from the motor winding feeds.

1 question so far......

Is the higher voltage regulator in the external PSU proving useful? As I have said, my external supply is currently unregulated but it would be easy to build another reg at about 26v to sit in the supply.

Cheers

[MartinT]

Before you go any further, Ian, what do you hear so far?

What sort of voltage dip are you getting on the unregulated side when starting up the platter, and then in steady state?

[UV101]

Hi Martin,

The running/ standing unregulated voltage is approx 28.5v. Under start up/ brake loads, the voltage drops to about 26v (although I have a DVM and it would be better to see the dip on a analogue meter!) The reg output appears to remain constant at 21.02v.

So far as sound goes, I cant really be subjective. The TT is new to me as is the cart (DL103 now nude). I've done a lot of research on the TT arm and cart and have added mass to the std arm (as suggested for this cart). The cartridge is fixed to a plate (sold as a stabiliser on eBay). I'm using a Sumiko headshell, a SL1200 achromat and a Michell clamp and I plan to machine a wooden case from some exotic wood (my father-in-law has a small milling machine so it shouldn't be too difficult) for the cart very soon.

My current listening environment is quite poor for TT use which I'm sure will be hampering the performance (horrible feedback). The TT is in the middle between the speakers but is about 18" forward. This is of course playing havoc with the sound. I'm quite confident that when I am able to resolve the placement, the performance will be far in excess of what I was expecting (its really not bad now considering)

Its fairly obvious to me that the external PSU should be better (although the original regulation is better than most to start!) and I'm no stranger to multiple PSU's regs so I just decided to go for it!

(Sorry for all that off topic but I should really explain why I'm unable to be subject other than "imho, it sounds pretty good )

So, back to the PSU. Given the voltage drop (not really surprising given the start up load etc) The voltage is dipping by about 2.5v given the fact that the internal regulation doesn't appear to dip at all, wonder what I could expect from a pre reg in the PSU????

Cheers