Difficulty level for AKSA N to N+ upgrade

CButterworth · « **on:** 17 Jun 2005, 05:43 pm »

I love my AKSA 55N. However, it is the "nonplussed" version. I built the original non-N version, got it working, then replaced the relevant bits for the N version.

I had a little difficulty, in that one of the traces began to lift from the circuit board, and I eventually had to mount one of the caps to the underside of the board. I also remember a lot of messing about with resistors to get the bias to a level within tolerance.

Everyone raves over the AKSA 55N+, and I am having a slight bout of "upgrade-itis." So, this begs the questions:

1. How much more work is the switch from N to N+?
2. Is there really that much difference? My guess is "Yes"
3. Hugh, is there a N to N+ upgrade kit. and at what price?
4. Do I dare risk ALL?

Thanks,
Charlie

PSP · « **Reply #1 on:** 17 Jun 2005, 09:12 pm »

Hi Charlie,
The 55N-->N+ took me a couple of evenings of soldering (and I tend to work very slowly). Setting the bias was another evening or two (since I check for 55mv quiescent multiple times, to be sure that I've got a stable and repeatable reading). Overall, the N+ upgrade is by far easier to do than the initial Nirvana upgrade. My DC offset was still good, i.e., I did not have to change any resistor values (other than those in the N+ upgrade) to reduce the offset. Break-in is really strange, just as everyone else has said many times.

The sonic impact of the N+ upgrade (in my system, caveat, caveat, caveat) was the least subtle change to my amplification I've heard since I swapped out my old NAD 7020 for my first AKSA 55. The improvement was stunning. To calibrate that statement, sometimes I can hear changes due to speaker wire or interconnects, often I can't. I can usually hear changes in PS caps, and I can hear the effect of soft recovery diodes in the PS.

I think lifting traces can often result from either applying too much pressure with the soldering iron when removing old components, or not getting all the old solder removed... then there is a small solder bridge to the old component, and when you try to remove it, it won't come loose. If you just pull harder, you will probably rip the trace.... instead, gently heat the connection and wick some more solder away. Sometimes the trace can pop when you put the new lead through the PCB... the lead catches the underside of the trace and pops as you push the new part home. The solution here is to feel the part as it goes in, and if it catches, play around until it goes in smoothly. Go slow, feel what you are doing, and--if you can--use a stand-mounted illuminated magnifying glass to watch what you are doing too (these are often pricy, but if you keep looking, you might find a decent one for $25-40).

You can definitely do this. The risk is minimal (if you are patient, the risk can be zero). The sonic reward is huge. Go for it!

Peter

PJ · « **Reply #2 on:** 18 Jun 2005, 03:56 am »

Too much heat can also lift the pads, although this is usually only a problem with SMT soldering with *tiny* pads.

Rom · « **Reply #3 on:** 18 Jun 2005, 07:04 am »

Hi Charlie,

1. How much more work is the switch from N to N+?
Answer
Not really as much as the stock to N but you need to change more parts
as far as I remember. The full instruction is writen with precision.

2. Is there really that much difference? My guess is "Yes"
Answer BIIIIIIIIGGGGGGGG YYYYYEEEEEEEESSSSSS!!!!!!!

3. Hugh, is there a N to N+ upgrade kit. and at what price?
Answer I normally got some special price so I don't know.

4. Do I dare risk ALL?
Answer I will second PSP's
You can definitely do this. The risk is minimal (if you are patient, the risk can be zero). The sonic reward is huge. Go for it!

Cheers
rom

AKSA · « **Reply #4 on:** 18 Jun 2005, 07:11 am »

Charlie,

To raise an AKSA to N+, you really should not be non-plussed...... all that's required is confidence and patience.

Cost is $AUD195 to upgrade, around $US150.

Performance jump is considerable, probably from 8/10 to around 9.2/10. BUT, it takes at least 150 hours to bed in, which is infuriating but unavoidable with the Black Gates used.

If your pcbs are unreclaimable, we can replace them of course, at slightly additional cost.

It ain't that hard, Guv!

Cheers,

Hugh

stepitup52 · « **Reply #5 on:** 21 Jun 2005, 01:26 pm »

~~~~ A common tip from stuffing up many copper tracks over the years. As PSP said, take it slow & if you lift a track, whatever component u r feeding thru - cap, resistor etc ... bend the lead over to sit on top of the track along to where u have no lifting. And prepare it first by using a scalpel blade or similar to scrape off the varnish and tinning over the track- back 2 bare copper.....probably only need to go 2-4 mm away from wots left of ur hole...then snip ur component lead 2 where u hit the start of ur undamaged track and run a bead of solder from hole along the lead - presto; new track, mechanical integrity and u don't hav 2 get a new PCB from Hugh & start again!!
I reckon LMP silver solder is the best 4 this because u can lower ur temp & minimise the risk of doing damage 2 surrounding components.
cb

CButterworth · « **Reply #6 on:** 21 Jun 2005, 02:06 pm »

I am reassured by the replies, and will endeavor to encourage my spouse in the idea of performing an upgrade to the AKSA. So far, all my upgrades have proven noticeable, so I should be able to justify the relatively small expense.

However, I may hold off for a few weeks, we're in the middle of a hot spell in the Phoenix area with temps over 114F (45C), I really do not want to add the heat from the soldering iron to our already stressed air-conditioning unit, which struggles to get to 80F inside our poor house

I suppose I should play Vangelis's Antarctica and chill-out

PSP · « **Reply #7 on:** 21 Jun 2005, 06:09 pm »

To underline stepitup52's point about low-melting solder, it seems to me that Cardas solder (Michael Percy) and Kester 63/37 solder--Mouser: part no 533-23-6337-18 melts a bit quicker and easier.... that must be a good thing for your parts and PCB traces.

You won't be sorry about the N+ upgrade; the sonic effects are not sublte. After I recieved my N+ upgrade, the parts sat on my workbench for several months because the music was so good (55N) that I didn't want to pull my amp from the system so I could work on it. Jens kept telling me, over and over, that I should get busy on the N+, that it would be a huge improvement, blah blah blah. Honestly, I had no idea how big a change the N+ would bring. Jens was right, bigtime

Good luck,
Peter