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Courtiestown - Naim Amplifier (Avondale) Upgrade Project

Good Evening All (again),

Mike - yes I only had that one reference to 100uH others do refer to values between 5 - 10uH such as Vishay Dale IHA-501/ 502. Just seeking confirmation re resistor values now.

100V/ 5A rectifiers should be more than adequate given I'm only driving a VBE for FE duties.

Is there a really, really good reason why such as Farnell list devices which are NLA. I just drilled down to a Panasonic 6,800uF/ 100V capacitor to be told it was NLA. I mean what use is a NLA component to anybody???

Regards

Richard
 
All major electronic suppliers does just that, Mouser and Digikey to name a few.
Fets are the real nightmare, here today gone tomorrow, Covid made it even worse. I guess, we have to bite the bullet

BTW, what's the brand of these polystyrene caps ? Mouser only stocks Xicon ones (limited to 50V last time I've checked).
 
Good Morning Ramona,

Yes I know all the major suppliers do it, it doesn't make it any less annoying. You drill down to something and see there are 10 alternatives listed and then find that 8 are NLA so you only have a choice off two in reality.

I actually finished revising my original Excel spreadsheet this morning (it has been very quiet on nightshift) so check this link out and it gives the Farnell Part No.'s for all parts (except a few which Farnell can't supply) - https://docs.google.com/spreadsheet...ouid=104404634061394323084&rtpof=true&sd=true

Regards

Richard
 
Richard Lines said:
100V/ 5A rectifiers should be more than adequate given I'm only driving a VBE for FE duties.
Click to expand...

Sorry , I've only just caught this - actually I think you'll want a higher PIV voltage, especially if you are running the front end rails up above 40v.

The reason is that the rectifier 'sees' [max output DC voltage - the peak of the inverse ] across it, which might well be over 110v. The usu estimate for min rating is 2.82 x winding AC output - so I'd go with 200v parts.
 
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Richard Lines said:
Good Morning Ramona,

Yes I know all the major suppliers do it, it doesn't make it any less annoying. You drill down to something and see there are 10 alternatives listed and then find that 8 are NLA so you only have a choice off two in reality.

I actually finished revising my original Excel spreadsheet this morning (it has been very quiet on nightshift) so check this link out and it gives the Farnell Part No.'s for all parts (except a few which Farnell can't supply) - https://docs.google.com/spreadsheet...ouid=104404634061394323084&rtpof=true&sd=true

Regards

Richard
Click to expand...
Gee, those RC55Y resistors are expensive these days. Or maybe I'm just old.
 
Mike Hanson said:
Whenever I've asked Les about inductors between cap pairs, he's always told my 12µH, so 100µH seems a bit high.
Click to expand...

Supplied by Les

51831884351_c3652357f2_b_d.jpg
 
laverda said:
Supplied by Les
Click to expand...

Graham - Thanks for this. Which capacitors are you using there? The 30mm diameter restricts you to around 6,800uF/ 100V as far as I can see?? This picture is CLCLR??? What was this for? What value resistor? As I've stated I'm looking to drive FE VBE's off a 0 - 50V transformer.

G6t4WK0.png


Regards

Richard
 
Graham,

I assume you removed the inductors for 'sonic' reasons?? I found these at Digi-Key - https://www.digikey.co.uk/en/products/detail/epcos-tdk-electronics/B82111E0000C021/3501168

Martin indicating the need for say 200V diodes complicates things. Farnell only seem to supply one 150V Schottky and that at 3A, RS don't appear to offer anything useful. Digi-Key have three 200V/ 5A options.

What are the collective thoughts on the capacity of the individual capacitors?

Regards

Richard
 
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150PIV/3A will be just fine!

High voltage and 'schottky' are mutually exclusive for physical reasons. But since the front-end PSU pcb is open to add a little series resistance CRC etc/ inductance as the side discussion, the diode type is ...unimportant.

I like Qspeed diodes if they are still available, at least as 'good' in terms of quiet recovery and they go up to 30A/300+ PIV ... )

Failing that, any rectifier that fits the pcb is good to go.
Just don't worry about it.
 
Good Evening All,

Thanks to all for the contributions/ pointers/ advice, it is much appreciated. That's me downloading 56Mb of zipped pictures.........

As that is two votes for 2,200uF I'll look some of them out along with Qspeed diodes. I was limiting my search to axial diodes as the MiniCap6 isn't really designed to fit DO-220 pattern devices although they could be made to fit..............

Looking at something like this for multiple mains connections:-

ULa077V.png


Regards

Richard
 
Good Morning All,

Another quiet nightshift although things will start happening later once the rig has deballasted sufficiently so we can eyeball the two aft anchor bolsters.

As 'we' don't know the exact whereabouts of the transformer I was buying off Alan I'm now looking at sourcing a suitable replacement. The specification is quite simple a 700VA 0 - 240V primary, 2 x 0 - 35V 5A secondary job not forgetting such nice add-ons as an electrostatic screen and GOSS band. The main sources I'm aware of are Canterbury, Tiger Toroids, Toroidy and Trans-tronic, are there any others?

Regards

Richard
 
Richard Lines said:
Good Evening All,

Thanks to all for the contributions/ pointers/ advice, it is much appreciated. That's me downloading 56Mb of zipped pictures.........

As that is two votes for 2,200uF I'll look some of them out along with Qspeed diodes. I was limiting my search to axial diodes as the MiniCap6 isn't really designed to fit DO-220 pattern devices although they could be made to fit..............

Looking at something like this for multiple mains connections:-

ULa077V.png
Click to expand...
I actually used a Series 222-415 as the ground star-point in my stereo NCC200 amp, using stacked MeanWell SMPS supplies to get ±50VDC.

3%20-%20SMPS.jpg


It was quick and easy. Now that it's running, I suppose I could switch it to a large crimp connector, but there's no pressing need.
 
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Richard Lines said:
Graham,

I assume you removed the inductors for 'sonic' reasons?? I found these at Digi-Key -

Regards

Richard
Click to expand...

Yes, they sit on the sound slightly IMO. I have found the FE transformer has has the most effect on the presentation. (Down the Naim route) Huge transformer, bigger, better sound. The HiCap as an example does not require (on paper) a large 500Va transformer for just two 24V supplies to feed a few 10s of mA of juice. I have recently been playing with a NAC102 and supplying each circuit with its own independent 24Vdc supply from 6 Avondale TPR4 regs

51834159220_ca928a76aa_b_d.jpg


51832484397_0ba55ac986_k_d.jpg


via a few different transformers. 150VA IE, 300VA off the shelf toroid (Farnells finest) and a bespoke 500VA Audio grade from Tiger Toroids (there is a difference in an Audio Grade toroid transformer)

The NACPC switching PSU was an independent LM317 I knocked up. ya very steam punk.

51832492067_56c67566c4_k_d.jpg


So some conclusions the rectifiers have a sonic signature, though I'm not sure if Naim still use 45A 2504s (half waved) but this is undoubtedly part (of a chain) of the Naim 'sound' or presentation.
A large transformer can have a significant influence on the sound. Pre or outputs, bigger more texture and wider sound stage with extra detail. Why should this be.??
The smoothing caps have less of an influence on the sound (known branded makes) don't buy cheap sh*t. I don't use inductors in the PSU, I used to but prefer without.
Don't over C the PSU I have run NCC300s on 10000uF per rail no issues to much uF sits on the sound.

Was it worth the expense time a effort to do this NAC102 project. It sounds better but not stunning and so no not worth the effort In my opinion. As Mr Clark so rightly said make a change and wait and see, (a week or so) then remove it you'll know which you prefer. Sorry I have to leave this here now domesticity calls.
 
Richard Lines said:
That's a very cheap way of getting 50V - I guess the big issue is filtering the noise??
Click to expand...
There's no noise from this supply. It's regulated, and the sound is remarkably clean. In some respects it's better than a linear supply. However, when the amp asks for "LOTS of juice NOW!" it falters a bit. I find that bass is a bit lacking and big dynamic transients are some stifled. In terms of detail retrieval and timbral nuance, though, it's wonderful.

Consequently, it was a good match for the Totem Mite in my bedroom. That speaker is a bit bass-heavy (surprising given it's diminutive stature), with gentle highs. Having an amp that's just a touch bass light with lots of detail was fitting. I even used a silver interconnect between the DAC/Pre and the amp in an attempt to brighten it further. The overall sonic signature is still rather polite, which is well suited to the bedroom.
 
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