Just finished Part 1, the PSU overhaul. I have the Phoenix back up and running with no issues (I triple checked all the of the work just to make sure).
Went with the big Nichicon 6800uf 35V KG Gold Tunes...saving the Mundorf Caps for the RE1
I have pics but I'll post those later .....
Edit Here are the pics ....
Before
After
Dis (sic) assembly notes: This is one PITA unit to get that pcb out of but it's not nearly as complicated as the head section will be (sigh). Still I like a challenge and such things never deter me from my mad pursuits of greater performance. Anyway what I did was make note of the trafo secondaries and which pads they were assigned to, marked the wiring. To get at that wiring requires you unbolt all the transistors first, unsolder the DC leads from the jacks on the back panel, unbolt the data ports,unbolt the 2 pcb standoffs, then push the pcb forward enough to clear the left hand debug switch, once clear of that flip the board over towards the trafos and unsolder all the secondary leads. You then have the pcb free from the chassis. The rest is pretty easy if you have the right tools. Total time including a few short breaks about 4.5 hours which also included triple checking polarity of the new caps and of course the secondary trafo wiring and the DC jack wiring.
The mod entails pulling all 6 mains filter caps and the 12 smaller caps on the board. The stock filtering capacity is pretty hefty for a preamp/head amp but I feel the unit could use some longer legs or more stamina not to mention better ESR rated caps, whether this mod accomplishes that goal remains to be seen but initial listening tests are positive. Ok stock capacity is 12 x 1500uf, 6 x 3300uf = 37,800uf . The mod consists of 12 x 2200uf, 6 x 6800uf (plus 6 PIO bypass caps for the large KG's) = 67,200 uf. Almost doubling the stock capacity.
PG, all of the mods (not including this one)) I've performed thus far have been very positive for the Phoenix and the RE1/CD7. This latest venture is likely the one that will yield the least in terms of a big jump. This will likely be a small refinement although I could be wrong about that. I need to let these new caps settle in before making any determinations.
One thing I have noticed is slight increase in dynamic heft and speed. Some further clarity in the bass region although that could be my imagination. At any rate my Phoenix is easily an order of magnitude above the stock unit (when you add up all the mods thus far, the cables etc). It would be interesting to compare a stock unit with mine side by side in a top flight 2 channel system. Hopefully the head amp mod will lift the performance of that section to that of the preamp section...if it does I'll be one happy camper. The second Part of this mod I'll get cracking on in a couple of weeks...the FBI-500 rebuild and mod (going to give it preamp outs and a ACSS pass through among other things) is on deck now (should have the L channel output stage next week).
Peete.
