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Naim hi-cap service

N

nucky

Eric
If I want to service the hi-cap what’s involved, I know the caps are very easy to replace what else do I have to do I am pretty good with a soldering iron
 
I'm sure this has been covered several times before but here goes (in order of importance):


  1. replace the two main capacitors
  2. replace the four tantalum beads on the regulator board
  3. remove and re-seat the LM317 regulators using fresh heat sink compound and mica washers
  4. use stainless steel nuts and bolts on the LM317s
  5. lift the bridge rectifier and apply fresh heat sink compound under it
  6. check and replace the DIN sockets if they show any sign of corrosion (given the low cost, I'd do this anyway)

malcolm
 
or altenatively just do 1 and maybe 2

Unless your HC is positively ancient or has been really abused the the goop will still be goopy.

Even the factory doesn't routinely reseat 317's and rectifiers.

They don't even routinely reseat transistors on power amp boards, even if the goop has dried and gone yellow.

You might possibly need to replace the goop under the c-sink since that joint will have to be broken to get access to the regulator board if you replace the tants.

I have not found any sonic benefit in replacing those tants - though very old ones probably should be replaced because they can go short circuit.

Obviously any dodgey socketry should be replaced but this is rarely necessary.
 
nucky said:
If I want to service the hi-cap what’s involved, I know the caps are very easy to replace what else do I have to do I am pretty good with a soldering iron
Click to expand...

Hi Nucky
Avondale do recon reg boards 65 quid
caps available also.
 
All 4 tants and the large caps and a little bit of new compound under the heatsink but let's face it, a preamp drawing a couple of hundred mA isn't to make it dissipate much heat.

Use the Kendeils from me or Les as the reservoir caps.
 
Totally agree on the Kendeils. Night and day difference in SQ.

While you're about it, you could consider some "upgrades".

There's a difference in opinion about the rectifier bridges, but I found another wonderful improvement in replacing the bridges with discrete HEXFred rectifiers. Between the Kendeils and the rectifiers, the noise floor drops into an inky abyss. Neither of these mods changes the sonic presentation. They just clean things up.

To my mind, the Avondale ASR module is an improvement, but it does alter the sonic character a bit. After installing an ASR, my wife at first thought that one of the channels was out. The solo guitar was so localized in space that a natural response was that only one speaker was working.

BTW, I've experimented with various alternatives, and I still prefer a suped up HiCap (for driving a NAXO).
 
Aren't the LM317 regs a special Naim spec/tolerance anyway? I would leave them alone personally and Naim never changed them when I had my Hi-Caps serviced.

The Kendeils are really good IMO, much better than the SLCE's (in a 250 anyway).

mat
 
I can see where a mis-understanding has occurred. When I typed 'remove and replace the LM317 regulators' my meaning was to put back the original regulators. I've edited the post and changed 'replace' to 're-seat'.

I'd also like to clarify that my list in post #2 was "in order of importance". Thinking about component costs:

step 1 is ~£50 and is done to improve performance since electrolytic capacitors deteriorate
step 2 is ~£6 and is done for safety reasons because old tantalum capacitors can fail

thus far that's ~£56

whilst you have it open:

steps 3 - 5 cost ~£3

replacing the sockets (step 6) is not essential but for the additional cost (~£12) you will have replaced just about everything that can deteriorate with use and time.

malcolm
 
I will service both of them with the kendeil caps and new tants as it is for the Naim 282 preamp the olive one was serviced in 2008
Thanks
 
Malcolm is definately right about the tants being desireable to replace, especially at circa £1.00 each.

I bought an olive hicap on the well known site recently, sold as 'spares or repair', at a good price.

One of the four tants had blown to bits - making a mess inside the casing.

If I could sort out how to post photos on this site, I'd happily post up the picture of what a blown tant look like - must of made quite a bang!

richard
 
rhgbristol said:
Malcolm is definately right about the tants being desireable to replace, especially at circa £1.00 each.

I bought an olive hicap on the well known site recently, sold as 'spares or repair', at a good price.

One of the four tants had blown to bits - making a mess inside the casing.

If I could sort out how to post photos on this site, I'd happily post up the picture of what a blown tant look like - must of made quite a bang!

richard
Click to expand...
I use photo bucket, where did you get the tants from
Thanks
hi-capp2.jpg

hi-cap22.jpg
 
Either Farnell - part no. 1457618
or RS part no. 538-2133

10uF 35v tantalum dipped radial capacitors 85 degree C - Kemet T356 series

99.8p each but minimum order quantity is a pack of 10
 
rhgbristol said:
Either Farnell - part no. 1457618
or RS part no. 538-2133

10uF 35v tantalum dipped radial capacitors 85 degree C - Kemet T356 series

99.8p each but minimum order quantity is a pack of 10
Click to expand...
Is it the same tants for the hi-cap 2? The hi-cap 2 has the blue ones the olive has the orange ones
Thanks
 
Don't forget that the tantalum beads are polarised and can produce spectacular fireworks if connected the wrong way round :eek:
 
misterc6 said:
Don't forget that the tantalum beads are polarised and can produce spectacular fireworks if connected the wrong way round :eek:
Click to expand...

They've exploded when hit with a high current supply for the first time too. CDSs were especially fun to turn on for the first time.

Mark.
 
I've just acquired a 1985 CB HiCap, it's clean, has Felsic 15000 micro Farad 63v capacitors in it, been using an Avondale MSX until now, it sounds a tad softer in presentation, but a bit more bassier (naim signature ?). Are the caps original ?

I can get Felsic 18000 micro Farad 63v here if they need replacing.

Felsic Caps

These or Kendeils ?
 
Yes they are the original 1985 issue.

The "correct" in the sense of best sounding thing for an HC is Kendeil 22000uf - LONGER VERSION

cheapest source is Naimly Linn on Ebay
 
I just got a pair of new Kendeils for my HiCap. One of them rattles! I'm assuming that's bad and it should be returned. Can anyone confirm if's thats actually a problem?
 
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