OK, so I am not electronically minded i.e. design and build an amp from scratch but have some engineering knowledge and can follow instruction e.g. have built a kit car and have wired in engine management systems.
So, without going into the ethics of clone amps, will the following list of parts work when wired together i.e. are the parts compatible. I also understand that the sound that comes out may be of variable quality but on the face of it this should provide a reasonable sound. I guess I have an itch to scratch to see if these random parts can sound as good as a second hand Rotel RB1050 or similar i.e. a commercial £150 stereo class AB amp.
Therefore looking at the following to provide a full dual mono stereo power amp:
Amp Boards - NAP250 clones, small form factor £22.50 - DIY NAIM NAP250 MOD stereo CLASS AB 80W+80W 8ohm D1047 Amplifier kit by LJM | eBay (showing performance test - finished board 2 PCS NAIM NAP250 MOD D1047 MINI Stereo 2 channel Power amplifier finished board | eBay
Power supply boards with 40000uf per channel, rectified £27 - 2x Audio Power Supply Amplifier Board 35A NOVER 10000uf/50V *4 Diode Rectifier 6010848619405 | eBay
Transformers - 225VA 2x25V toroidal (one per channel) which should give 35V DC out of the supply boards above that the amp boards need £56 - 2 Output Toroidal Transformer, 225VA, 2 x 25V ac | RS Components
(or would I be better going for a 500W SMPS ?)
I know I will need heat sink/connectors/mains plug etc. but have an old Rotel amp that I can scavenge parts from an re-use the box.
I then have the option of adding speaker protection/soft start with these £14 - 2pcs Mono UPC1237 Speaker Protection Board C1237HA Mirror Symmetry Circuit New | eBay
and powered 12v AC one of these £12 - 2 Output Toroidal Transformer, 30VA, 2 x 12V ac | RS Components (or should I keep it totally separate and use a transformer for each protection unit)
Sorry for all of the questions. All comments welcome and are there any parts that could be replaced with better options (other than not starting at all) ?
Thanks in advance.
So, without going into the ethics of clone amps, will the following list of parts work when wired together i.e. are the parts compatible. I also understand that the sound that comes out may be of variable quality but on the face of it this should provide a reasonable sound. I guess I have an itch to scratch to see if these random parts can sound as good as a second hand Rotel RB1050 or similar i.e. a commercial £150 stereo class AB amp.
Therefore looking at the following to provide a full dual mono stereo power amp:
Amp Boards - NAP250 clones, small form factor £22.50 - DIY NAIM NAP250 MOD stereo CLASS AB 80W+80W 8ohm D1047 Amplifier kit by LJM | eBay (showing performance test - finished board 2 PCS NAIM NAP250 MOD D1047 MINI Stereo 2 channel Power amplifier finished board | eBay
Power supply boards with 40000uf per channel, rectified £27 - 2x Audio Power Supply Amplifier Board 35A NOVER 10000uf/50V *4 Diode Rectifier 6010848619405 | eBay
Transformers - 225VA 2x25V toroidal (one per channel) which should give 35V DC out of the supply boards above that the amp boards need £56 - 2 Output Toroidal Transformer, 225VA, 2 x 25V ac | RS Components
(or would I be better going for a 500W SMPS ?)
I know I will need heat sink/connectors/mains plug etc. but have an old Rotel amp that I can scavenge parts from an re-use the box.
I then have the option of adding speaker protection/soft start with these £14 - 2pcs Mono UPC1237 Speaker Protection Board C1237HA Mirror Symmetry Circuit New | eBay
and powered 12v AC one of these £12 - 2 Output Toroidal Transformer, 30VA, 2 x 12V ac | RS Components (or should I keep it totally separate and use a transformer for each protection unit)
Sorry for all of the questions. All comments welcome and are there any parts that could be replaced with better options (other than not starting at all) ?
Thanks in advance.
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Hi Ugg and welcome,
You might have gathered, if you read many recent posts and even further back in this marathon thread, that early Naim sound is unique. It's not comparable to any Japanese amplifier I've ever listened to but is characterised by a subtle, particular musical quality labelled PRT (pace, rhythm and timing) by the flat-earth audio believers and Naimologists among us.
Whilst any of the NAP clone kit amplifiers could be fine-tuned to suit low power rating models in the original amplifier range, NAP 250 is a little different in that it was intended for use with regulated DC supplies which need to be at the full maximum +/- 40V supply level to safely rate the amplifier at 2 x 125W/4R. However, NAP140 has unregulated +/- 34V supplies and is much cheaper to build. It's also much as you propose to build and similar to many other clone builds posted here.
There are also finished and working clone versions you can buy from China at around £140 + £35 postage. These builds use the ZeroZone kits which do have a few minor issues but importantly, they also include most of the correct and essential component types and original pattern PCBs. Other kits seem to come with mostly generic semis and caps, which leaves you with a large shopping list of replacements to buy if you expected original or at least decent sound quality.
It's quite disappointing to realise you may have saved a few dollars there but had to spend several more and sometimes more than once, in order to source the expensive but necessary components that weren't supplied. Don't be misled by cheap kit prices and pretty pictures. None of that makes up for dissatisfaction in having to spend hours looking for the reason it sounds poor and for possible solutions.
You might have gathered, if you read many recent posts and even further back in this marathon thread, that early Naim sound is unique. It's not comparable to any Japanese amplifier I've ever listened to but is characterised by a subtle, particular musical quality labelled PRT (pace, rhythm and timing) by the flat-earth audio believers and Naimologists among us.
Whilst any of the NAP clone kit amplifiers could be fine-tuned to suit low power rating models in the original amplifier range, NAP 250 is a little different in that it was intended for use with regulated DC supplies which need to be at the full maximum +/- 40V supply level to safely rate the amplifier at 2 x 125W/4R. However, NAP140 has unregulated +/- 34V supplies and is much cheaper to build. It's also much as you propose to build and similar to many other clone builds posted here.
There are also finished and working clone versions you can buy from China at around £140 + £35 postage. These builds use the ZeroZone kits which do have a few minor issues but importantly, they also include most of the correct and essential component types and original pattern PCBs. Other kits seem to come with mostly generic semis and caps, which leaves you with a large shopping list of replacements to buy if you expected original or at least decent sound quality.
It's quite disappointing to realise you may have saved a few dollars there but had to spend several more and sometimes more than once, in order to source the expensive but necessary components that weren't supplied. Don't be misled by cheap kit prices and pretty pictures. None of that makes up for dissatisfaction in having to spend hours looking for the reason it sounds poor and for possible solutions.
Ian, many thanks for the reply and good to know that all is not what it seems before I splash out any readies.
I understand the Naim signature sound and as I am currently using 8" studio monitors (Mackie HR824) connected to an Audio GD dac and passive preamp I think the Naim sound is what I am looking for rather than a relaxed/fruity NAD sound (been there as well).
The reason I was looking at these is I am considering an active three way speaker build (probably based around the Statement Monitor but with a base that will house three amps and the crossover/dsp) and I am weighing up the various amplification options i.e.
Any suggestions ?
I understand the Naim signature sound and as I am currently using 8" studio monitors (Mackie HR824) connected to an Audio GD dac and passive preamp I think the Naim sound is what I am looking for rather than a relaxed/fruity NAD sound (been there as well).
The reason I was looking at these is I am considering an active three way speaker build (probably based around the Statement Monitor but with a base that will house three amps and the crossover/dsp) and I am weighing up the various amplification options i.e.
- Something like the above - ebay kits bolted together to give six channels of passive power that can then feed a passive crossover
- Passive COTS power amps e.g. Behringer A800, Crown 1002 or Rotel RB1050/870BX or RB1066 plus passive crossovers
- Passive COTS power amps plus minidsp (either 4x10 or two 2x4)
- Hypex FA253 or 123 plate amps with built in dsp
Any suggestions ?
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Active speakers are a quite different matter for NAP type amplifiers. Naim's extreme designs like the Statement, are something radically different again. At £205,000 ea. you'd expect that much and a lot more.
I have listened to only a couple of serious attempts at active speakers driven by Naim clones, though with many tweaking adjustments between them by an enthusiastic guy who tried a lot of things but eventually gave up on the idea when conventional amplifiers (P3a/P101 and even Chipamps) consistently sounded better and easier to match with the crossover and also a DSP system.
I could be wrong due to little direct involvement but I don't think Naim's original NAP models are appropriate for use in active speakers. I would expect any similar clone that was fitted with original type components, to be problematic in an active system too. Of course, you are welcome to try this for yourself because this is DIY and we do a lot of odd things for the learning experience. I would check out your other choices for power amplifiers in the appropriate speaker forum here first though.
I have listened to only a couple of serious attempts at active speakers driven by Naim clones, though with many tweaking adjustments between them by an enthusiastic guy who tried a lot of things but eventually gave up on the idea when conventional amplifiers (P3a/P101 and even Chipamps) consistently sounded better and easier to match with the crossover and also a DSP system.
I could be wrong due to little direct involvement but I don't think Naim's original NAP models are appropriate for use in active speakers. I would expect any similar clone that was fitted with original type components, to be problematic in an active system too. Of course, you are welcome to try this for yourself because this is DIY and we do a lot of odd things for the learning experience. I would check out your other choices for power amplifiers in the appropriate speaker forum here first though.
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Ian, many thanks again for the guidance, much appreciated.
I am coming to the conclusion that using the Hypex FA123 may be my best bet. It gives me the option of starting out with a dsp driven crossover which I could then go hybrid and build the recommended passive crossover and use the Hypex dsp for room correction. I could even have them switchable as they can be set up to store 3 filter, one totally flat/pass through, one for room correction, one fir development. The Statement monitors can be built with a switchable near/far wall passive crossover aswell. Still planning but getting there.
I am coming to the conclusion that using the Hypex FA123 may be my best bet. It gives me the option of starting out with a dsp driven crossover which I could then go hybrid and build the recommended passive crossover and use the Hypex dsp for room correction. I could even have them switchable as they can be set up to store 3 filter, one totally flat/pass through, one for room correction, one fir development. The Statement monitors can be built with a switchable near/far wall passive crossover aswell. Still planning but getting there.
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