SX-Amp and NX-Amp

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#45
Just to clarify, there are two PSU's you can use with the nx-Amp

1. Basic PSU. This is the same board as the sx-Amp. You need to change the capacitors to 50V types 22 milli Farad - everything else is the same otherwise. There is no speaker muting or protection with this board. One board will supply a stereo set-up.

2. PSU +Protection. This was designed specifically for a stereo nx-Amp set-up - everything is on one PCB. It has speaker muting, DC offset protection and overcurrent detection.

For the transformer, my recomendation is 500 VA, but you could get away with 400 VA.
 
#46
Bonsai said:
Just to clarify, there are two PSU's you can use with the nx-Amp

1. Basic PSU. This is the same board as the sx-Amp. You need to change the capacitors to 50V types 22 milli Farad - everything else is the same otherwise. There is no speaker muting or protection with this board. One board will supply a stereo set-up.

2. PSU +Protection. This was designed specifically for a stereo nx-Amp set-up - everything is on one PCB. It has speaker muting, DC offset protection and overcurrent detection.

For the transformer, my recomendation is 500 VA, but you could get away with 400 VA.
Click to expand...

For me it is the second one for sure but it will depend on what PMI is willing to go for.

Thanks
Do
 
#49
nx-Amp circuit boards are on order, as of July 3, so given the intervening July 4th Holiday, and shipping, I expect them in my hands the week of July 15. Cost per board will be $10 give or take a few cents, so around $20/stereo pair plus shipping. In the US that is about $2-3 for a padded envelope, shipped by regular mail.

Anyone interested in a set, please post below, or send a pm.
 
#50
PMI said:
nx-Amp circuit boards are on order, as of July 3, so given the intervening July 4th Holiday, and shipping, I expect them in my hands the week of July 15. Cost per board will be $10 give or take a few cents, so around $20/stereo pair plus shipping. In the US that is about $2-3 for a padded envelope, shipped by regular mail.

Anyone interested in a set, please post below, or send a pm.
Click to expand...

I'm in for a stereo set (2 amp pcbs and 2 psu pcbs).
I have built the Hiraga super class A 20w version and I liked it very much. This sx or nx amp input stage is based on Hiraga. However, since I have improved the sound of my Hiraga by changing the output bjt by semi-lateral MOSFET than I may try the same with the nx amp....

Looking forward to getting your pcbs 😎

Thanks!
Fab
 
#51
fab said:
I'm in for a stereo set (2 amp pcbs and 2 psu pcbs).
I have built the Hiraga super class A 20w version and I liked it very much. This sx or nx amp input stage is based on Hiraga. However, since I have improved the sound of my Hiraga by changing the output bjt by semi-lateral MOSFET than I may try the same with the nx amp....

Looking forward to getting your pcbs 😎

Thanks!
Fab
Click to expand...

Hey Supah Fab!

I actually heard Fab's modified version of the Hiraga Super Class A 20W and it sounds stellar!!!

Looking forward to this one!

Ciao!
Do
 
#53
ivanlukic said:
So far that's PMI, pinnocchio, fab and me. Three 2pcb sets are still "homeless".
Click to expand...

That's quite surprising to have not that much interest because this amp should probably be a killer:violin: maybe it is vacation time....

It is quite obvious to me that Bonsai knows what he is doing and he likes the sound of this amp. Look at the quality of his amp documentation which is very good. He really put DIY community to a higher level :up:

Fab
 
#55
Perhaps as pics and reviews appear here, or in the other thread, the interest will increase.

Here is my list so far. The amp boards are out of fab and supposed to be shipped to me today or tomorrow.

PMI (2 nx-Amp + 1 nx-PSU)
ivanlukic (2 nx-Amp + 1 nx-PSU)
pinnocchio (2nx-Amp + 1 nx-PSU)
fab (2 nx-Amp + 2 PSU)
evette (2)
potepuh (2)

I think this is fine, I can always reorder as needed. Since we are still operating under the same discount as I used when I ordered my through-hole VSSA boards, there is little benefit in higher quantity until we cross the line somewhere around 50-100 pieces. The main incremental cost is shipping small-ish orders separately.
 
#59
fab said:
...since I have improved the sound of my Hiraga by changing the output bjt by semi-lateral MOSFET than I may try the same with the nx amp....
Click to expand...
Interesting, please post how that goes when you get that far, perhaps I shall try that with a second set if we re-order. Usually I try to build at least one set according to the instructions, and listen to it for a while... and as I said before, this seemed to generous an offer from Bonsai to pass up... 😀
 
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#60
Bonsai,

I see in BOM that there should be winding details for L1 in the text, but there is none AFAI can see. Would you please add that description when you return home?

(I pasted this from separate nx thread, so no need to answer in both threads)


 
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