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Avondale HCR200 plus Qudos

stackowax

stackowax

pfm Member
I installed a pair of HCR200s and Qudos boards into my NAP250 over the weekend and noticed that the HCR200s have two Ov connections points whereas the 250 boards had just one (see photo...the red circles identify the two OV points). I'm just wondering if (a) if these are for a different kind of set-up than the NAP250 or (b) if I'm supposed to use them in a NAP250 install. If the latter, I'm not sure what would be connected to what. I've submitted the same question to Les and I'm sure he will get back to me in due time, but I'm just wondering if anyone here has experience with installing these boards in the NAP250 and can explain what the second OV point is for.

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I think it could be something to do with powering the boards with a front end and rear end separate power supply...as in the voyager
 
There's a clean ground and dirty ground. It's not rare and it's VERY important that you correctly connect them BOTH, hence the warning on Les's packaging about it. If ignored expect possible fried loudspeaker on the menu...
 
Thanks. I saw Les's message, but I didn't really understand it. So, sounds like what I need to do is to connect two wires to each of the two OV points (in the lower part of each of the HCR200 boards) and then solder the other end of each wire to the same place that all of those other green wires are soldered to (the metal bar that connects the two negative speaker wire terminals). Yes?

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Sorry I misread your OP... there is an extra ground on the amp boards compared to the original NAP250 modules and on the Avondale amp boards I was just doing for someone there was actually a printed warning that both sets of grounds must be used and I thought this was what you were referring to... in fact it's the one's on the regulator boards! It is perfectly feasible to have clean and dirty ground on the regulator as well of course and I've just had a look at Avondale diagrams on the matter and they show the output ground on the HCR200 (nearest the heatsinks) connecting to the clean input grounds on the amp modules ie the grounds furthest from the heatsinks on the amp boards. The grounds furthest from the heatsinks on the HCR's go to the main "star ground" at the speaker terminals exactly as you have drawn on your pic. This makes good sense to me technically also.....
HOWEVER.... the Avondale diagrams do not even show a second ground on the amp board nor is anything mentioned... so whether this is to be assumed as present, ie if fitting the HCR's to a unit which already has Avondale boards fitted and it only shows the changes to be made rather than including wiring presumed to be already there, or whether it is from old versions that maybe had but one ground, is something I wouldn't want to second guess.
 
I did wonder if it might have something to do front and and rear end PS, but just wasn't sure. I'm eager to hear the new boards, but I think I better wait to hear from Les. Haste makes waste, as they say.
 
stackowax said:
I did wonder if it might have something to do front and and rear end PS, but just wasn't sure. I'm eager to hear the new boards, but I think I better wait to hear from Les. Haste makes waste, as they say.
Click to expand...

It's not front and rear end PS etc no. It's too late at night for me to be trying to explain the black art of grounding I'm afraid! I believe the way I described it is correct but to be blunt it is an issue for Avondale rather than for Arkless Electronics and as it's Les's baby he should know any peculiarities of his own product better than me:)
 
This just in from Les...

“The two 0V terminals are there in case the module is used for another purpose i.e. the Voyager amps so no need for another connection as the two terminals are common to the same track.”

Thanks for everyone’s efforts to help. Looks like I’ll have a chance to listen to the new boards tomorrow.
 
I have four HCR200 and one pair (I presume earlier version) have only one OV pcb male spade connector so I crimped two cables in to the same female conector -job done.
 
When I recap a 250 I link the 0v terminals on the smoothers and run a thick wire from it to the ground bar between the speaker terminals, makes a big difference to the sound quality.

Pete
 
Pete MB&D said:
When I recap a 250 I link the 0v terminals on the smoothers and run a thick wire from it to the ground bar between the speaker terminals, makes a big difference to the sound quality.

Pete
Click to expand...

Thanks Pete for that sugggestion. I'll give it try.
 
It is a lovely set up. Hopefully you have checked the age of the 15,000uF smoothing caps as well?
 
I did put some new Kendeil smoothing caps in the amp sometime in 2009. So maybe time to start thinking of replacing them? (As I recall, they were a bit of a pain to source.)
 
Well after a few days running in, a customers Qudos I've sorted (fitted Qudos modules plus built and fitted DC protection board etc) is sounding very nice indeed I must say. Congrats to Les on a nice product there!
 
well its nice to hear you like the Qudos amps Jez :eek::D great to hear an independent view from some one who has never been a NAIM sound fan:rolleyes:
I do think that Qudos and NCC300 amps are very good, and a marked step up from the Quasi complimentary output amps
Alan
 
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