NAP250 amp boards & regulator boards

[lohk]

Found it:

Naim NAP250 regulator boards | Page 2 | pink fish media

This is puzzlin to me. Why do we not need an elcap here to "smooth" the voltage?

 

[JeffYoung]

Interesting; now that you mention it I had heard something about them using full-wave instead of bridge rectification, but never found any detailed-enough pictures to confirm. Cute trick of using one of the extras for the front-panel lights.

Mouser has the MPSAs.

 

[lohk]

I have posted a lot about that a long time ago - maybe I will find the images again.
You cannot see that clearly with many of the images found in the net, but a good proof is the fact that the two green wires run from the transformer to the centre ground between the main caps.

 

[avtech]

Payment sent thanks.

JeffYoung: 6 amp, 2 original_reg, 4 inverted_reg PAID
lohk: 2 amp, 2 inverted_reg PAID
john.luckins: 2 amp, 2 inverted_reg PAID
avtech23: 2 amp, 2 inverted_reg PAID
ultima legion: 2 amp (original_reg, inverted_reg, or both?)
jean michael: 4 amp, 4 inverted_reg
gary s: 2 amp, 2 inverted_reg PAID
Quantensprung: 4 amp, 2 original_reg, 2 inverted_reg
Skunark: 4 amp, 2 original_reg, 2 inverted_reg PAID

 

[JeffYoung]

This is puzzlin to me. Why do we not need an elcap here to "smooth" the voltage?

The elcap and resistor form an RC network which doesn't do any smoothing at very low frequencies. The zener and resistor are essentially a shunt regulator which works all the way down to DC.

 

[JeffYoung]

I have posted a lot about that a long time ago - maybe I will find the images again.
You cannot see that clearly with many of the images found in the net, but a good proof is the fact that the two green wires run from the transformer to the centre ground between the main caps.

I did buy a NAP180 for the case (and NA001 transistors) so I can open it up and photograph it (assuming it's the same as the 250).

 

[vasillis]

Does anyone know where to get genuine Onsemi MPSA06/56s?

I have mpsa56.
sent me a PM with your adress and i sent a few.


BR
Vasilis

 

[coolnose]

Jeff,

this is slightly off-topic but would you mind sharing a pic (ideally mounted) of the circular mil spec connectors you mentionned earlier in the thread ?

They are pricey, but I don't built 10 amp a year either... so this got me curious.

Cheers,

Max

PS: I found the datasheet/catalog page I have acces to pretty poor to be honest...

 

[pem1]

Hi all please put me on waiting list for the boards from gb

 

[JeffYoung]

Jeff,

this is slightly off-topic but would you mind sharing a pic (ideally mounted) of the circular mil spec connectors you mentionned earlier in the thread ?

They are pricey, but I don't built 10 amp a year either... so this got me curious.

Cheers,

Max

PS: I found the datasheet/catalog page I have acces to pretty poor to be honest...

Hi Max,

I will indeed. While the cost is eye-watering, they are really sweet.

(I should have a board built-up by next week. Ping me again if you'd rather see just a mock-up sooner.)

 

[JeffYoung]

Note: 2 amp means 2 amp boards; i.e. enough for one stereo amplifier.

JeffYoung: 6 amp, 2 original_reg, 4 inverted_reg RECEIVED
lohk: 2 amp, 2 inverted_reg PAID
john.luckins: 2 amp, 2 inverted_reg PAID
avtech23: 2 amp, 2 inverted_reg PAID
ultima legion: 2 amp (original_reg, inverted_reg, or both?)
jean michael: 4 amp, 4 inverted_reg
gary s: 2 amp, 2 inverted_reg SHIPPED
Quantensprung: 4 amp, 2 original_reg, 2 inverted_reg
Skunark: 8 amp, 4 original_reg, 4 inverted_reg PAID

--- waiting list ---

pem1: 2 amp (original_reg, inverted_reg, or both?)

Cheers,
Jeff

 

[coolnose]

"Ping"

 

[JeffYoung]

Quick mockup (in actual use I think I'd add some heatshrink at the end of the wire down to the shoulder):

Cheers,
Jeff.

 

[gary s]

Hi Jeff,

Those mil style gold connectors look the part. They seem to have a large contact surface area - are they quite tight when mated, i.e. do you need to give them a good tug to disconnect?

I would also add heat shrink down to the shoulder to "finish" them off - very professional looking.

 

[JeffYoung]

They're pretty tight. The threaded collar on the housing they normally go into is push/pull so that you can get them apart when there's 30 pins in the housing.

 

[JeffYoung]

Note: 2 amp means 2 amp boards; i.e. enough for one stereo amplifier.

JeffYoung: 6 amp, 2 original_reg, 4 inverted_reg RECEIVED
lohk: 2 amp, 2 inverted_reg SHIPPED
john.luckins: 2 amp, 2 inverted_reg SHIPPED
avtech23: 2 amp, 2 inverted_reg SHIPPED
ultima legion: 2 amp (original_reg, inverted_reg, or both?)
jean michael: 4 amp, 4 inverted_reg
gary s: 2 amp, 2 inverted_reg SHIPPED
Quantensprung: 4 amp, 2 original_reg, 2 inverted_reg
Skunark: 8 amp, 4 original_reg, 4 inverted_reg SHIPPED

--- waiting list ---

pem1: 2 amp (original_reg, inverted_reg, or both?)

Cheers,
Jeff

 

[gary s]

Thanks Jeff, for the "shipped" confirmation on the pcb set and the reply on those mil spec pcb pins.

 

[pem1]

Both please jeff

 

[gary s]

One other question with those mil style gold connectors Jeff, how are you attaching the wire - solder or crimp. From the photo you show I think you have just slid the wire into the socket for the photo, as it looks "too clean".

 

[JeffYoung]

Hi Gary,

They are soldered, but yes, it's just slid in in the mock-up.

I don't have it in front of me but if memory serves there's a solder wick hole so you can solder it with the insulation all the way up to the pin like it is in the mock-up.