Phono11 - Brain Damage

[NickG]

Well I wont clame to be a wise one, but

I would still like one of the 'wise ones' to come back with an answer to - 'what happens if resistors have (2) paths to ground.

IMHO, nothing, the only time I could possibly see it being a problem was if one of the paths was carrying a current from another part of the circuit, but thats not to do with two paths, thats the reason star earth normally help.

[Black Stuart]

Thanks Nick,
I thought that might be so. Incidentally I found another erroneous through hole on an earth run, which I plugged with a PCB pin and solder. Also the reason given in Adrian's instructions for the mistakes on the PCB is a porky, since I had one of the first Pre-modules - the circuit was never like that.

Black Stuart

[buddam]

Hi Stuart

you mentioned in an earlier thread (I think) using tantalum Res to upgrade. I'm doing the CF mod shortly and wondered about using these. My current boutique preference is Kiwames but I have these eveywhere & Sometimes the sound is too smoothe and refined, eg on rock. I wondered if I could get a bit more attack and detail by putting tants in the Phono II. WOndered if you went straight from standard kit to Tants or if you'd tried any others in between (eg Rikens, Kiwame).

Regards

Adrian

[John Caswell]

Hi all,
In response to the question "what happens if a resistor etc." It is going to depend on the circuit.
Cathode follower very little if any effect at all.
Low gain stage - ditto.
Hi gain stage - could have instability/hum problems
Power output stages - ditto
RF stages ie above 2-3 MHz - instability, hooting , failure to work at all, unable to realign etc.

Cathode follower conversion, - Build as bog standard then upgrade, as you will then have a reference, good or bad, to relate to.
This is my standard answer to this question, relating to way back when and has stood the test of time. It also means that if you have problems someone here can/will sort it out, without you suddenly saying "Oh by the way the output Tx is not the standard one supplied, as I thought this was better!"
Very offputting.

Regards

John aka Dr John

[Greg.]

Hi Adrian,

Look carefully at this photo of my CF conversion and you'll see a couple of Vishay bulk foil R's which I used for the 1K and the 820R resistors. Expensive but nice and work well alongside the Kiwame's and Dynamicaps. I like the balance of the sound



Best wishes,

Greg

[NickG]

Dr John, my resistor answer was given on the basis of the circuit in question being the Phono-II, and the resistor in question being the cathode resistors.

[buddam]

Hi Greg

thanks for the pic. I don't see any Vishays (but the vishays I have come in the black square package - TO 220 or some such). Are they the smaller green ones next to the Kiwames? On the Dynamicaps - I might go for the Obliggato or Mundorf (or Benny's close approximation at DIY Paradiso).

Dr John - I take your point, but having tweaked so many components in other amps I know that the boutique parts mentioned will be an improvement. So I might as well minimise my labour.

Adrian

[Greg.]

Hi Adrian,

I said you had to look hard Look immediately to the right of the 1M 5W Kiwame and there's another immediately behind it to the right of the vertical pair of Kiwame's. They are very small which makes the price harder to swallow. Bought from Michael Percy.

Best wishes,

Greg

[Black Stuart]

Hi Adrian,
I think the best way is to audition resistors is in the shunt mod. I can hear differences between Kiwames and Rikens and have yet to listen to Tants, RS carbons and Maplin metal film. I think this way you may save quite a bit of money.For what it's worth uprate resistors, which I always stand off from a PCB and think carefully about wiring. I may yet be persuaded to try Greg's favourite from IPl.

Also remember that signal valves can be very microphonic and Pearl Coolers or the silicon tube dampers from M.Percy in the States (which I would like to try) can make a substantial difference to the sound - is anyone putting in an order to Percy?

Black Stuart

[buddam]

Greg & Stuart

thanks. I may be ordering from MP. Will Know by Weds or Thurs. Have you tried Audiokit in Italy?

Adrian