PhonoII and PsuII - schematics and

[pre65]

Hi Bob, do you use CCleaner ?

If not download it and run every day, I do mine last thing at night before I run the anti virus scan on AVG, with auto shutdown.

http://www.piriform.com/ccleaner

[Richard]

Hi Bob, yes seconded Phil for the CCleaner, really excellent.

Hi Greg, This is a really good phono with much more bass, treble and everything in between! Several things may now be apparent and adjustable.

1 The character of your cart (what is it?) will have a bearing
2 Coupling caps have a flavour
3 Valves too
4 The first stage cathode bypass caps fitted or not
5 Setting the trimmer cap

I use 0.1uF and 2.2uF Soniqs same as you. After trying many combinations of the above I use the bypass caps on first stage, GE5751 valves, and found 190pF on the 3.18 network gave the correect riaa and square wave response.

I don't know how yours is set but certainly using Ecc83 with cathode bypass caps on first stage gives a somewhat brighter and louder balance (subjectively and literally as there is more gain). If you let us know the set up at present I can suggest which moves will change it subjectively. I say subjectively as all the changes I've done and listened to have been checked and adjusted on the bench for riaa accuracy also.

[bob orbell]

Thank's for the help on the CCleaner, Philip and Richard, I will get Janet to instal it when she comes home. BOB

[Richard]

Hi Greg,
You could just remove/not fit the trimmer and use a fixed cap instead,

[Greg.]

There does appear to be a bit of confusion creeping into this thread particularly as Greg (as I understand it) has PSU and Phono II (not III).

[colin.hepburn]

Originally Posted by Greg.

There does appear to be a bit of confusion creeping into this thread particularly as Greg (as I understand it) has PSU and Phono II (not III).

Hi Greg
Yep this is my fault carrying on from Greg’s post

[Richard]

Thread split for Colin's posts

http://www.world-designs.co.uk/forum...ead.php?t=6153

[Really Aardvark]

Well it's a week further on and a few miles(?) of vinyl groove has passed under the stylus. It's all settling down quite nicely. But it ain't perfect yet. The biting top edge has gone but the soundstage has lost the depth it gained when I changed from an Origin Live arm to a 3009 S2. The sound is back to being a single plane in line with the front of the speakers - this I need to fix.

To reply to Richard's points
1. The cart is the V15Vmxr I got from Boondi. I find it tonally very neutral and it still surprises me just how far down it goes.
2. Thanks to Bob for his kind offer of caps. Unfortunately my soldering isn't up to cap rolling on PCBs (yet). Just getting the Jupiters out I managed to lift a couple of pads and few mm of track. I'll have to stick with SAs for the time being.
3. V1/2 are JJs with a Chelmer E83CC for V3.
4. First stage is bypassed with Oscons as recommended.
5. No trimmer cap as it's PhonoII. C16/17 is 220pF but with a 14.4k resistor in series.

So more like a Phono 2.5 then. Prime for a set of 5751 unless I need to add any of the extra supply components around V3 anode?

Still it's the best phono stage I've had so far. And I've still got the Lundhal transformers and a Denon 103 to ring even more changes with.

And i'll sign off now as Demand 5 has finally got the cricket highlights up.

[bob orbell]

Good to hear it is getting better Greg, I dont know what others think of Chelmer valves, but I would junk it if I was you, I find that all I have tried are very grity and too bright I can recomend Philip's Jan for a nice smooth sound. BOB

[Richard]

Hi Greg,

Yes it sounds like the edge has gone off the new Soniqs caps now (normal) and has left the sound somewhat flat. This is to be expected as 220pF in the 3.18 network is a bit much with Ecc83 (in my tests anyway) as you spotted. The V15 should be a good cart to evaluate and set up the amp with as there are no complications from step up Txs and its response will be good.

Options might be,

1) Change the 3.18 network 220pF to 190pF for Ecc83 and investigate other varieties. The JJ are pretty good but the Chelmer unknown. Mullard and Thorn short plates are good, US types are smooth and deep. EI Yugos are very dynamic. All will be a tad brighter with the cap change.

2) Fit 5751, no other changes needed, great tone and may be a tad brighter with that 3.18 setting

3) (most exciting option for me but not tried it yet ) fit 3 Russian 6n2p. Their output impedance is a little lower and capacitances a little higher than the other 2 types so the 220pF value should be about right. The only change would be to rewire the heater links which are just tagged on the pcb pads. I will get around to trying this some day as it is a fantastic valve in the CDp but I've not much other exp with it yet.

The extra decoupling caps C13/14/15/16 could be fitted also but I've not A-B'd the change so don't know how it affects sound.