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Avondale NCC300 Monos Underway

laverda said:
Looking, you have the 0 speaker returns to the rectifier end of the PSU?? If so try relocating the NEG 0 speaker wire to the clean end of the PSU used for the outputs...power up and wait 3 days. (may be longer) I know the preferred connection is as close to the transformer 0's as possible (dirty end of the PSU) but IMO the clean end of PSU to be better with the 300's . If its not revert.

How much F have you on the front end PSU?
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Thanks for the tips...appreciated!

So, yes... the speaker neg is on the end nearest the transformer (must admit I thought it was supposed to be) but as its literally a straight copper track to the other end I didnt think it would make a lot of odds....But of course I will try it and see (and swop back if not as you suggest)

All the caps are 10K uF on all the boards so front end has 30K for plus and same for minus
Its possible this might be a little much for the amp to be "light on its feet" ...do you think i should swop the final Nichicon's for 6.8k ?

thanks for all the help
 
Mynamemynaim said:
Thanks for the tips...appreciated!

So, yes... the speaker neg is on the end nearest the transformer (must admit I thought it was supposed to be) but as its literally a straight copper track to the other end I didnt think it would make a lot of odds....But of course I will try it and see (and swop back if not as you suggest)

All the caps are 10K uF on all the boards so front end has 30K for plus and same for minus
Its possible this might be a little much for the amp to be "light on its feet" ...do you think i should swop the final Nichicon's for 6.8k ?

thanks for all the help
Click to expand...

Yes IMO I think the front end has toooo much F and those inductors between each cap may not help either, others may suggest otherwise. (Its easy to link them out and see) You only need 10,000uF (Max) on the front end PSU. I used, with good result.. 6600uF on each rail (3x2200uF per rail) for the front end PSU without any additional filtering as there's plenty with the on board regs. I believe Les used 6800uf for his voyagers but not absolutely sure. To much F can make an amp sound dull and or slow.

I'd give the 6.8k a go on their own...
 
So after some more listening I think I've identified a problem / issue

My existing layout is with the speakers (kudos S20) being very far apart either side of the fireplace ...about 11 feet apart
With seating about 8 feet in front

Now the existing Avondale puts a nice sound stage in the middle and between the speakers

The ncc300 puts a huge soundstage across the whole room....and so sounds a little thin in the middle ....
Trouble is I cannot really move the speakers... only maybe angle them in some
 
Mynamemynaim said:
The existing Avondale puts a nice sound stage in the middle and between the speakers

The ncc300 puts a huge soundstage across the whole room....and so sounds a little thin in the middle ....
Trouble is I cannot really move the speakers... only maybe angle them in some
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Yup, toeing them in a bit more should improve that.
 
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From your listening position:- try right speaker just pointing over your left shoulder, left speaker pointing just over your right shoulder. Looks extreme but works for me. Look at YouTube @ newrecordday he's done a few videos as I recall.
 
From my listening chair I can just see the inside edge of both IMFs. I’d like them a bit farther apart but the room won’t allow it. I’m not complaining, Tin Pan Alley sounds absolutely blistering :D The NCC300s are performing really well :)
 
So the 300 monos have been on for a couple of days and seem a lot more focused now... with a much better defined sound stage...and starting to pick up on rhythms I've missed in familiar tracks..

But still not totally blown away with the sound ...so have ordered new parts to make a pair of new hackercap boards for the front end power supply... with 6 x 2200uF caps each and new diodes etc..
Will try the suggestion of loosing the inductors as well...they can always be dropped in again as a trial if I like the new boards
 
Mynamemynaim said:
have ordered new parts to make a pair of new hackercap boards for the front end power supply... with 6 x 2200uF caps each and new diodes etc.
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It's worth noting that Avondale often uses their NCM1 power supply module with the NCC300, which has a fuse, soft start module, and separate supplies for input and output stages. On the input supply, there's just a single pair of 3300µF caps. I'm not sure that you'll see much benefit with 3 pairs of 2200µF caps with intervening inductors.
 
Thanks Mike....but as mentioned I'm not planning to use inductors in this set of boards...and the amp should only "see" the last 2200 caps?
 
Mynamemynaim said:
Thanks Mike....but as mentioned I'm not planning to use inductors in this set of boards...and the amp should only "see" the last 2200 caps?
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Ah right... I saw "regulators" and my brain also echoed "inductors". :)

However, if you're using links instead, then what your input stage will see is 2 x 3x2200, or 2 x 6600µF. (Capacitors in parallel are added.) That's double what's on the NCM1, although might have marginally lower ESR, given each of the three capacitors on each side is smaller than the 3300µF in the NCM1.

With the regulators in the input stage, though, I would expect this to have no impact.
 
My NCC300s have Avondale Cap six boards for the output stage with 6 x 6800uf caps and 4 x 12mH inductors. Front end has Minicaps with 6 x 6800uf and 4 x 4.7 ohm resistors. Caps are Nippon Chemicon.
 
Ultimately, a power supply with more caps is not going to hurt it. It's just unlikely to help all that much either. At least that's my take on the subject.
 
Chops54 said:
My NCC300s have Avondale Cap six boards for the output stage with 6 x 6800uf caps and 4 x 12mH inductors. Front end has Minicaps with 6 x 6800uf and 4 x 4.7 ohm resistors. Caps are Nippon Chemicon.
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Thanks for the clarification Chops!
At present mine is set a little different with the front end having the bulk of the smoothing (6x10000uF and 4x 10mH chokes) and the back end just having 4 x 10000uH caps

When the other boards are made in a day or so (6 x 2200uF caps only) for the front end....I might try swoping the current front end supply to the back end...and see how that sounds
 
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so the all new 2200uH boards are done / tested / working so i just need to pop them in and see if there is any difference in sound

I have to say the Ncc300 amp has finally started to get its act together and start sounding good...so maybe I didn't need these after all??
 
To my reasoning, NCC300 should make big difference for difficult loads.
With the NCC230 moving away from TO3 output transistors it would be interesting to see that for NCC300.
 
So I'm putting the two new boards in...and before I start I think...I'll just check the bias first.
They have been on for several days now

Now I know why one felt hot and the other felt tepid...it's wasn't because one was above the other on the shelves....it was because the bias on one had settled to 110mA and the bias on the other had risen to 160mA
Why wasn't that my first thought?
Its so obvious now:oops:

Perhaps I should put a thermocouple on the heatsinks with a digital readout on the front..
 
I have an issue that to be honest...I've been trying to ignore...but it keeps coming back to mind to brother me

When I set the bias...I can set both amps to the same mA settings for current draw
Or
I can set both amps to the same voltage across the resistors

But I cannot set both amps to have similar current draw and voltage??
One reads approx 120mA and 1.196v
The other reads 120mA and 1.148v

Why would that be when the component values and importantly the (regulated) DC input voltage are the same?

Is this something I should be worried about?
Should I set the amps for the same draw or the same volts (assuming I cannot correct the problem)
The amps sound great as is...but that doesn't stop this bothering me

Any thoughts anyone please?
 
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