beginner question about Park G10r amp scratchy pots and mods

[OcdFx]

a very quick note, I am new to electronics and this will be my first project that isn't replacing a power socket on a laptop or something similar, so I apologise if I sound like I am talking rubbish.

I have a park G10r amp and both gain pots are scratchy gain 2 is a 'b200k' pot I have scoured the internet but cant seem to find one other than this http://www.wellgainelectronics.com/oemrotarypotentionmetervr16mmb100k.aspx  this is probably a stupid question but can i just use a 220k pot? Gain 1 is a 10k pot which is much easier to find. is it better to use linear or log pots for the gains?

I also want to mod the amp for a better clean sound, so suggestions here would be greatly appreciated.
Schematic here http://music-electronics-forum.com/attachments/5142d1239975835t-kerry.pdf

IC 1 + 2 are JRC4558DD
IC 3 is JRC072DE
IC 4 is TDA2030

I read somewhere that swapping the JRC4558DDs for RC4558Ps , the JRC072 for an OPA2604 and the TDA2030 for a TDA2050

Ideally I will be swapping the speaker but I dont want to spend too much £ on this little guy when I could be saving up for a new 100W amp.

thank you for reading.

[OcdFx]

whoops,

schematic link update:

http://music-electronics-forum.com/attachments/5142d1239975835-kerry.pdf

my bad.

[stringwanker]

Hi!

Do you know the master volume pot value of Park G10? I can't see the value on it. Is it A10k? Also, do you know the value of the fuse?

TIA!

[Mark Hammer]

The clipping diodes are always in-circuit, which means that you can't turn the gain up very much without introducing distortion.  So, if you want to improve the clean sound, then what you want is to install a toggle switch to lift one end of those two diodes for clean, and reconnect them for dirty.  That should take care of one of your challenges.

Use of a 250k Gain 2 pot instead of 200k won't change low gain settings, but will make highest gain settings more distorted.