Can anyone offer advice on how to replace the pot in my KGSSHV?

[loz_the_guru]

Hi all,

I purchased a KGSSHV recently, and whilst overall i'm very pleased with the sound, the pot installed is cheap and unfortunately has some balance issues at lower volumes. It looks to be a modular type pot, and bizarrely has 4 lugs per channel rather than 3. 

I've managed to get hold of what I'm told is a rather nice TKD 4CP 2500 pot, which has three lugs per channel. Can anyone offer some advice on the correct way to go about wiring it in? 

Looking at the old pot, there looks to be a set of bridged lugs on the far right which go directly to a piece of wire bridging the inputs at the back of the amp, as well as left/right input and output wires from the pot to the headphone socket. One set of lugs in the middle is left unused. Let me know if the photos aren't sufficient and I will snap a few more. 

Any advice? I have a multimeter somewhere to test bits if required...I have decent soldering skills but no real electrical knowledge. I did put together a Bottlehead amp a few years ago, but the instructions are so fool proof it was almost like building Lego.

Thanks all!

 

Photos: https://imgur.com/a/MEjBSzJ

[Pars]

The pot you currently have in the amp is an Alpha (or Sung Huei) RK2142G (datasheet attached). The 4th pin is a loudness tap. So basically, transfer the existing wires straight across to the TKD replacement. Watch the heat on this; try to make good mechanical connections and don't linger with the soldering iron. Looking at your first pic (the TKD), the pins in order from left to right would be ground, wiper, and input, or 1, 2 and 3 corresponding to the attached RK2142G datasheet.

The Alpha pots aren't bad at all, particularly for the price, but not in the same class as the TKD. BTW, where did you obtain the TKD from?

RK2142G.pdf

[loz_the_guru]

Brilliant, thanks i'll give it a go in the near future. Two quick follow up questions - is it worth using fancy solder or is any reasonable 60/40 stuff fine? Also can I just confirm the pin out correspondence of the new pot vs the data sheet from left to right is 1, tap, 3 according to the data sheet? Just looking again and if i've got the data sheet diagram the right way around in my head it looks to me like on my current pot the '2' pin has been left unsoldered?

I bought the TKD from http://www.diyaudio.vn/. It was a bit of a git to find any stockists, but the chap I spoke to was very helpful and replied promptly to all my questions. I'd recommend them.

[Fitz]

28 minutes ago, loz_the_guru said:

if i've got the data sheet diagram the right way around in my head it looks to me like on my current pot the '2' pin has been left unsoldered?

The tap pin is the one not soldered on your current one. If you're looking at the top right image in the datasheet, that's not a picture looking at the bottom of the pot, but the PCB layout the pot would fit into.

[mwl168]

A much better idea is to see if you can obtain one of the pot PCB from a GB (or other sources) some time ago so you don't need to solder directly to the pins on the pot.

No need for fancy solder IMO. I have solder from Cardas, WBT and good old Kester and don't believe either one makes an audible difference. Get a good quality solder and solder the joints well is key. 

[loz_the_guru]

Thanks all, will pop a post into the GB thread as the PCB sounds like a good idea. It was actually that thread which lead me to seek out the pot in the first place.