Restek Fantasy amp cap upgrade + opamps and Bursons!

[jacco vermeulen]

Originally Posted by HornTube

the big white ceramic resistors are really nasty.

Whenever i see 0.15 Ohm cement wirewound power resistors in parallel i wonder if they're the regular product or a low-inductance interleaved wire variety.

[HornTube]

Originally Posted by SimontY

Interesting ideas coming out I see. I had no idea anyone disliked the Alps Blue pot. I use one in my preamp and I'd often wondered if there were gains to be had from upgrading - but I only see very expensive options.

Any pot recommendations from Mr HornTube? And don't say Moroccan Black or White Widow

I made extensive listening tests with friends regarding the pot issue. It came out that (the cheap ones aside - too high tolerance etc.) Alps is the worst! The black Alps is better but not very much, Noble is even better. Panasonic is the best non-ladder attentuator I know - I think Audio Note UK using it also. But here is my tip: Buy the cheap ladder att. at eBay - from HongKong or China. They solder the 0.5W Dale resistors on it. Quiet good. The sound is VERY different in comparison to a normal pot. It excels in stage depth, detail & speed. But I would not recommend it for thin or analytical sounding amps cos it is surprisingly revealing. One must be careful cos the difference between Alps blue & ladder att. is like listening to a different amp! So Panasonic is a safe bet and will not hurt anyone. The blue Alps is really killing space & detail & speed - if you like to sleep in front of your stereo - first choice!

[SimontY]

Fascinating info, thanks. I've never compared pots really, except for when I changed out a linear Vishay one and a cheap log carbon one for the Alps - their channel balance was too poor and the Alps is first-rate in this regard. I've often wondered if the stepped attenuators improve things much. It looks like I'm going to have to try. Revealing is fine with me, I have a great preamp and first-rate cd player.

Sorry to thread-jack Ian, but maybe this info is interesting to you too. Trouble is finding a motorised alternative, there aren't many.

[HornTube]

Simon, you are using open baffles? I love it
Please more info on your preamp.

[SimontY]

I'm using cheap OBs but in my sig there's a link to much better ones I'm still putting together. The preamp is just a simple buffer designed by Pedja Rogic, using S-Power regulators, Kiwame resistors, the Alps Blue pot, CMC silver/copper sockets and Mundorf foil wiring. PSU decoupling is Ruby ZA. Naked caps and 80VA toroid for the fun of it.

[jacco vermeulen]

Ahhh, another Makro/Metro offer scrounger on the block.

[SimontY]

Makro's fun

[dtses]

Cheers Ian

have the same Restek as you do and pretty happy with it, although it has one trivial problem - i could distinguish and hear some music even when the volume control put to silence.
Do you have the same issue and could it be somehow fix, how do you think?

[UV101]

Hi!

I have exactly the same problem. Also, at very low volume, there will be a balance problem. This is all due to the Blue Alps volume control pot.

At some point, I will look into changing it but for the moment, I use the remote all the time so options are limited.

I can't tell you how much better a change to all the caps made. Much tigher and much more dynamic. The std preamp sections is average to be fair and the change to discrete opamps and rework again made a large difference.

If you're brave enough, there is plenty to be gained from an already very good amp

[dtses]

Hi,

thanks for info, now feel a relief about this balance issue

I'm thinking now about changing all the caps to Nichicon KZ or FG and the big 10000uf ones to smth. Not sure is there any point to buy expensive Mundorf or BC 114/ 154 series or Kendeil...recently have found Rubycons on ebay, how do you think, does it worth to try them? Also regarding the rest of caps, maybe it's better to find some replacement with OSCONs or Panasonic FC?

Already have done the following mods:
-replaced inlet with Furutech
-mains cable to Belden 19364
-all the original wires on pbc to silver 1.00mm
-speaker binding pots to CMC
-replaced oxidized speaker cable (pbc->speaker terminals) to Kimber 4TC (have 8TC from amp till speakers)

Now it's time for caps and opams