Nad 214

[Vrystaat]

Gooday all,
Does anybody know of upgrades on a NAD 214 poweramp that would improve SQ ? Caps or transistors ?

Regards

[sakis]

normally in a NAD 214 you expect to find :

---In the main power supply capacitance is lower than was supposed to be ( there is mounting area on the pcb for more ) and it could be nice to add ...


---Also adding bypass capacitors down under the electrolytic you replace especially in the front end power supply will be nice to do

--- Use of low quality capacitors in the stabilized front end power supply, that also run kinda edgy combined with some temperature might result to plenty of leaks while in other similar amps they actually run much longer there .....better quality ,105 dg ,and maybe higher voltage might be joy ...still size and make can be tricky

---choice of input capacitor is poor and many changed one using better quality than a simple mkt 1mfd

---The protection circuit regarding temperature is made with muting transistors in the input ....IE If amplifier gets warmer than supposed to input is muted Point is that many think that removing transistors form the input makes the amp more clean ( as less in the signal path is possible ) a nice option will be to replace the transistors with audio grade relay

---depending on the serial number you might find that idle is 50% less than specified on service manual ...to my understanding you could follow the service manual instructions or even go up to 30% more than that with any problems

---Finally you need to inspect both main boards for soldering issues ....

here is some pictures and if you need a schematic you can always email me

[Vrystaat]

Hallo Sakis,
Thanks for the info. I have got a diagram, so I will really appreciate it if you can tell me which components to change and maybe some values as well.

Regards
Jan

[tvrgeek]

Did they REALLY mount the transformer with a steel shunt like that?

Modern electrolytic are physically smaller so some gains may be possible. Check the catalogs. As it has 4 caps, are they sperated by a really small resistor to make a pi filter? Or are the caps for each side?

I see it has space for twice as many outputs. From my reading, that has a big advantage providing you have enough drive.

[pdul]

The 218THX is allmost identical, but with twice as many output transistors pr. channel

[pdul]

and the transformer is standing up like a wheel, and the powersupply has 8 4700uf caps.

[sakis]

Originally Posted by tvrgeek

Did they REALLY mount the transformer with a steel shunt like that?

Modern electrolytic are physically smaller so some gains may be possible. Check the catalogs. As it has 4 caps, are they sperated by a really small resistor to make a pi filter? Or are the caps for each side?

I see it has space for twice as many outputs. From my reading, that has a big advantage providing you have enough drive.

mounting is kinda weird but still proper isolation and no "winding" over the trafo

as about the size of caps things are not exactly as you describe them cause NAD 214 is not vintage equipment old may but not vintage problems in capacitors are related not especially to age but mostly in quality and range ...so picking up caps might be tricky size wise ...

main filter capacitors are tall and thin .... so that is the number one problem as seen from the photos i had to mod the amplifier to fit nippon caps

[Vrystaat]

Sakis,
Are you talking about caps C202- 205 and C210 - 213 ?


Regards

[Vrystaat]

Hallo Sakis, From what I have read on the internet it is not good to mount a toroidal like this. The mounting seems to cause a shunt over the transformer. Low volts but high current. The transformer should only be mounted from one side. Does this not waste a lot of the transformers power that can actually influence the working of the amp ?

Regards
Jan

[Vrystaat]

Goodday all,

Can somebody plse give advise on how the toroidal is mounted with a shunt over the transformer. I 've read it is not good practice to mount a toroidal like this in Post 2.

Regards
Jan