Restek Fantasy amp cap upgrade + opamps and Bursons!

[Bonsai]

I am surprised that you believe that with the Alps pot set to min volume. I use a 10k Alps blue velvet (RK27) on my X-Ultra Mini pre-amp, and do absolutely not have this problem. Are we talking about the same pot here? If yes, then this might be a signal switching or layout issue, rather than the pot. Intersted to hear your comments.

[SimontY]

Originally Posted by UV101

This is all due to the Blue Alps volume control pot.

Hi Ian!

You're unlucky with that pot, as the Alps Blue is sold on its excellent channel balance. Mine is superb at low volume.

[UV101]

Originally Posted by 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

I couldn't get the bursons to work in the power stage but I didn't scope it to see if they were driving into oscillation etc. Mine are LME49710HA in the power stage. All the caps in the power stage are panasonic FM (I think) and I cant recommend doubleing the PSU caps to 2 x 10,000uf per rail enough. For me, there is only one cap for this job "F&T" who also made the Mundorf SI's for them (so I'm lead to beleive).

As yet, I've not replaced any internal cabling bit now you've got me thinking. especially as I have a couple of 2.5m lenghts of 4tc kicking about!!! Phono sockets and speaker posts have been on the cards for a while too!

Do you have any pics of your work?

Originally Posted by SimontY

Hi Ian!

You're unlucky with that pot, as the Alps Blue is sold on its excellent channel balance. Mine is superb at low volume.

To be honest, I've not looked any further into it. It could well be the external gain but I'd assumed the pot would be the weakest link. I could swap the balance over on the pot to see if I have more gain in one channel than the other and the problem swaps to the other channel. As I'm definatley not aware of this issue at listening volume, i'd still guess at the pot. Also, on the basis that the pot should effectivly drive the input to gnd at 0 volume regardless I still suspect the pot.

So in summary..........I suspect the pot (too many suspects the pot in there!!)

Edit - its a few years old now and crackles a little so it needs replacing anyway. I'd like to play with a lightspeed att. Driven off the original pot but thats just a passing thought at the mo........

[SimontY]

I heard a Lightspeed pre once and it surprised me with how HUGE the soundstage was compared to two active pre-amps.

[UV101]

If I go for it, It will be used to control the preamp section much in the same way as the pot is now although I will test it as a completely passive pre section too!

[SimontY]

It would be really interesting to hear about how it works in such scenarios.

[HornTube]

Nichicon sounds warm and lower-mid oriented - but not very speedy and lacks a little bit of the detail. The BC's are rather analytical with a little plastic taste, I would recommend EPCOS - the best of the large cap fraction - technically & soundwise. Elna is very good, better than BlackGate IMO. Oscons are only good for digital circuits - never ever use them otherwise. FC's are great, rather warm but not too much - second choice after Elna's highend caps.

[dtses]

Originally Posted by UV101

Do you have any pics of your work?

Hi Ian,

I did have somewhere... probably need some time to find or simply take few pictures of the amp as it's now.

HornTube

thanks for advice
do you mean Elna Silmic II or Cerafine is good as well?


Btw, forgot one important upgrade to amp's appearance - Titanium bolts on the front chrome plate. Still waiting for them but once receive could post some pics as well

[HornTube]

Silmic II, Cerafine, Stargate & Tonerex - they all sound great. Espicially the Silmic & Silmic II are very natural and faultless.

The Panasonics are also very natural sounding, maybe a tad worse than ELNA.

Rubycon ZL, ZLH, ZLA & BlackGates: Icy, cold, screaming HiFi, emotionless, static, destruction of the rhythmical flow, poser, here here I'm a very expansive cap - do you hear me - screeeeeeeaaaam, unpleasant, nervy, bodiless, there can't be too much highs. I have a bag full of this crap... - the caps for the beginners not for the connoisseur.

[SimontY]

LOL! It's cool to hear someone really speak their mind.