View Full Version : 5.6pf cap in later 321 board


new naim boy
23-12-05, 03:30 PM
Has anyone added this cap on a 321 board, in a 32.5. Was it worthwhile? If so could you send me some pics, as I can see where to connect it but I'm not sure of where's the best place to drill.

Merry Christmas

Aidan

bivalve
23-12-05, 03:39 PM
Aidan,

I've just done it last night (10pF actuually) to Issue 2 boards and it was a nice little improvement. You will need to check what 'issue' your boards are to get help. It should be under the logo and board number.

It sorted out a top end sibilance that appeared I think when I went to two SRs in the pre. You may not hear much if you havn't got SRs but I'm just guessing.

David

hacker
23-12-05, 03:51 PM
I've also just done it, but with 6.8pf silver mica caps. It was a great improvement in the treble, but I'm using 4 local SRs (1 per gain and 1 per buffer) in my 62. I think this really comes into its own with faster psus.

bivalve
23-12-05, 04:09 PM
Hacker,

Way to go! You were right.

Aidan,

You might consider soldering the cap to the underside if you can't proceed topside. I actually bought some C0G ceramic caps with this thought in mind, which are smaller and flatter. But I got Mica caps in OK topside.

David

new naim boy
24-12-05, 05:40 AM
Hacker:
I have some of these 6.8pf silva mica caps, left over from some work I did about 7 years ago on an old quad amp. However, I can't remember if they are bipolar or not. They look like the exact ones sold at farnell - and they have no markings to indicate +/-. Can you enlighten me?

The boards I have are the 321/3 version, and I'm not running any sregs. I don't think I have any prolems with treble, but have noticed that this is a Naim mod so definately worth doing.

hacker
24-12-05, 06:30 AM
They're bipolar - just stick 'em in any old way!

new naim boy
26-12-05, 11:03 AM
Well, they're in.

First impressions are good, but I think they will need to burn in.

new naim boy
30-12-05, 01:25 PM
I added these caps at the same time as doing several other mods to my 32.5:
1. silmic's in feedback position.
2. oscon's on power rail.
3. bc128's onstead of tants in 321 boards.
4. all boards except 321's removed.
5. output to power amp directly taken from 321 board via bnc phono connector, using solid core silver wire(overkill I know but it was left over from an old job so I thought I may as well use it.

At first I could tell there was more treble but the sound seemed hard and I must say unpleasant.

Everything did seem to burn in and improve ater a few days. But there was a significant step forward when I powered each 321 board separately from the two supplies from the hicap. The musicality of the 32.5 came back, but there was more detail in the treble.

The next step is to improve the earth connection to the 321 boards.