OK, new NX build 🙂
Few pics for now...:
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Few pics for now...:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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Bonsai has had his account disabled.
He is unlikely to respond.
He may have contact details on his website where all the design and build details are given.
He is unlikely to respond.
He may have contact details on his website where all the design and build details are given.
I hope Bonsai won't mind me posting the quote below, taken from his website (Ovation Symphony Line Preamplifier - see comment section at bottom):
"(...)I will continue to support any sx and nx amplifier builds and questions but from hifisonix.com only. I will do a new DIY class A amp soon (‘kx-amplifier’) that uses the same foot print as the sx amp but offers much better specifications.
I also started a small company selling equipment professionally – you can view the products at Ovation High Fidelity - Home."
And will just add for the record, that the comprehensive HiFI project/Audio design write-ups he has posted on Hifisonix.com are pure gold for the DIY interested. I recommend reading them all - twice at least 🙂
"(...)I will continue to support any sx and nx amplifier builds and questions but from hifisonix.com only. I will do a new DIY class A amp soon (‘kx-amplifier’) that uses the same foot print as the sx amp but offers much better specifications.
I also started a small company selling equipment professionally – you can view the products at Ovation High Fidelity - Home."
And will just add for the record, that the comprehensive HiFI project/Audio design write-ups he has posted on Hifisonix.com are pure gold for the DIY interested. I recommend reading them all - twice at least 🙂
Please correct me, if I’m wrong (double sided PCB’s);
– On the SX-AMP PCB, I need to install a wire link on J2.
– The J3 GND on the amplifier PCB, I connect to SIG 0V on PSU.
– ZNA on PSU, connect to ZN on AMP board
– Speaker GND, I connect to 0V
– So there is 1 GND connection free on the PSU.
– On the SX-AMP PCB, I need to install a wire link on J2.
– The J3 GND on the amplifier PCB, I connect to SIG 0V on PSU.
– ZNA on PSU, connect to ZN on AMP board
– Speaker GND, I connect to 0V
– So there is 1 GND connection free on the PSU.
sx amplifier
hi ben 123 did you find out how to wire the sx amplifier up ? as ime having problems myself ?? ta andy
hi ben 123 did you find out how to wire the sx amplifier up ? as ime having problems myself ?? ta andy
I got a technician build me an SX-Amp. Two things I thought he deviated from what I asked which is to stick faithfully to the specs as documented. First he skimp on the heatsink, substandard for what is “substantial” hence he installed fans which are noisy & annoying. Second, he did not use the specd power transistors and used instead 2SC5200/2SA1943, BD139/Bd140 in lieu of KSA1381/KSC3503.
While I can have him replace the current heatsink with beefy ones to get rid of the fans, I am however not sure if the substituted transistors had any effect with SQ. The sound I’m getting with the finished unit is, with lack of better words to use, mechanical and thin compared to a Hiraga 20W which I also have. The Hiraga have more body (voice & instruments) and more engaging. The SX-amp is biased at 1.1A at a rail voltage of 22Vdc.
So may I ask those who have experience comparing w/ different power trans specific to the SX if the transistors mentioned above have large impact on the SQ and replacing them with design specd would improve the SQ, or what I’m hearing from the SX now is how it really sounds. My first time hearing an SX.
Would appreciate any comment. Thanks.
While I can have him replace the current heatsink with beefy ones to get rid of the fans, I am however not sure if the substituted transistors had any effect with SQ. The sound I’m getting with the finished unit is, with lack of better words to use, mechanical and thin compared to a Hiraga 20W which I also have. The Hiraga have more body (voice & instruments) and more engaging. The SX-amp is biased at 1.1A at a rail voltage of 22Vdc.
So may I ask those who have experience comparing w/ different power trans specific to the SX if the transistors mentioned above have large impact on the SQ and replacing them with design specd would improve the SQ, or what I’m hearing from the SX now is how it really sounds. My first time hearing an SX.
Would appreciate any comment. Thanks.
Attachments
bridge diode D1(ground lift) -->J3 GND -->chassis
For the wiring, You can see more detailed explanations in NX-amp document.
And About ground lift, refer this link,
Earthing (Grounding) Your Hi-Fi - Tricks and Techniques
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That's a great looking build. Very nice. I hope you are enjoying it. I love my SX which I eventually got a custom Toroidy transformer for dual 17-0-17 and 400VA. It delivers exactly the right supply voltage and there is no noise or hum at all. In my "den" - a small room it is very powerful.
I recently ordered the nx boards from ebay. I had a quick conversation with Bonsai via his website and he cautioned me that I may hear hum if I use a toroid without a shield and belly band.
Has anyone gone the route of buying off the shelf for their toroid transformer and run into a noise/buzzing issue?
I contacted Plitron and they have a $1500 min order.
Has anyone gone the route of buying off the shelf for their toroid transformer and run into a noise/buzzing issue?
I contacted Plitron and they have a $1500 min order.
Try Toroidy or Antek and be done. I ordered Toroidy, excellent quality. Just google and you’ll find their webpage.
Best,
Anand.
Best,
Anand.
Arif,
That is way, way too small I am afraid. You are using a sheet of aluminum which will have s very high K/Watt figure. The amp will get thermal runaway like that.
Your heat sink should weigh about 1.5 kgs minimum per channel.
That is way, way too small I am afraid. You are using a sheet of aluminum which will have s very high K/Watt figure. The amp will get thermal runaway like that.
Your heat sink should weigh about 1.5 kgs minimum per channel.
Thank you so much for your advice and very quick response, i have some heatsinks.. that is for trial only, i Will try to get another ones...
I am sorry is it possible to set sx amplifier to be lower bias? What do you suggest voltage read on r 0.33 ohm 5 Watt..
Just my opinion that for trial couple days i am willing to run sx amplifier in lower bias.. then after all ok i Will rise the bias.
Thank you so much
Best regards