Jolida Amp Mods

Early B.

I'm considering taking my Jolida SJ502A integrated amp to the next level. I've completed the first level of modifications which included:

* Coupling capacitors: Sonicraft Sonicap .22uF/600v
* Signal Ground capacitors: Sonicraft Sonicap .47uF/600v
* Power supply bypass capacitors: Sonicap high voltage units
* Volume control: Alps Blue Velvet pot
* Balance control bypassed
* Diodes: Fairchild "Stealth" rectifying diodes in the rectifying stage of the power supply.

Now I'm considering these additional mods as defined by Response Audio:

* Power supply filter capacitors: upgraded to higher capacitance/low ESR pieces for even better dynamic control. Total of 6 pieces.
* Signal path resistors: Dale/Vishay 1 watt 1% non-magnetic Metal Film (x24 pieces)
* Grid stopper resistors: Japanese Riken Ohm Carbon Film units solder directly at the tube pins (x4 pieces)
* Tube emitter cushion resistors: Dale/Vishay 5 watt 1%, non-magnetic
* Dale/Vishay 3 watt 1%, non-magnetic resistors utilized in the bias stage allowing for either EL34 or 6550/KT88 output tubes
* Internal wiring: Quality 22 gauge copper wiring
* RCA input jacks: Replaced with higher quality gold plated pieces
* Subwoofer output (will sacrifice one input)

My question is whether or not the additional mods are worth the effort. Not sure if there will be an appreciable difference in SQ. Any thoughts?

madmax

I would say yes, but of course it all depends on what it costs. The power supply capacitors should make the most difference. The wiring is OK but remember, most of the parts are mounted on a PC board rather than being point to point wiring so I'm not sure much improvement will be had there.
madmax

organ

That's gonna cost you quite a bit. The cheapest and most effective mod I can recommend is to triode strap the amp. btw, are you using the 4 or 8 Ohm taps?

Maurice

Early B.

Thought about it...If I did any more mods, I'd probably limit it to the power supply caps as Max alluded to. To conserve costs, I'd buy my own caps and have someone install them. That's how I did the first set of mods. Or maybe I'll just leave it alone. Hadn't decided yet.

I plan on holding onto the Jolida for a while, so I'm trying to maximize what I already have. I think if I started down the component upgrade path again, I'd quickly run into diminishing returns. In other words, it would probably take a lot of money for a nominal improvement in SQ.

I'm using the 8 ohm taps.

organ

Switch over to the 4 ohm taps.

You have not run into diminishing returns just
yet. That triode strapping I told you about is THE cheapest and most superior tweak I've done to my amp.

All it requires is FOUR resistors. It can be done in about 20 minutes. Talk to your techie and see what he'll charge you. Your output power will be reduced by half but the result will amaze you. Anyways, half the power output is only 3db less, so no biggie.

Maurice

Early B.

Switch over to the 4 ohm taps.

Tried that this morning. It sounded flat and lifeless with my speakers.

Early B.

After listening to my system today, I decided to leave it alone for now. It sounds really great to me, so why bother? I think I'm gonna spend more time auditioning tube gear and speakers so I can hear what a "better sound" actually sounds like. Gotta find what I like most and go from there. But so far, I think I've built a system that sounds phenomenal given the restraints that I have -- space, budget, WAF, etc.

steveinaz

There you go Early, don't mess with success; you'll regret it everytime.