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Hiraga Le Monstre

Dan K said:
I have a set that the chap from ebay and DIY audio matched (he's Igor) to as close as was possible. He has a few other sets. You would almost end up in a bidding war with each other for who wanted the closest matched MOSFETs and whether you wanted the lowest noise or the most gain. Easy enough to get the SLB board from the USA. Better to order an individual board and slip under the $50 duty threshold. Then just get the SLB BOM from DIY audio and click the Mouser order link.

I've all the bits, just need a case and a pair of traffos..
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I can get a dual-rail SLB board for £28, is that all I need unless doing dual mono?
 
Just remembered I have a matched quad of LSK170/LSJ74 that I bought as spares for my M2 so that’s a start :)
 
Dan K said:
That's the one.. Then the Moser BOM. The SLB is not cheap, but it should be utterly silent.
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Getting very tempted to try this... have an Arcam integrated I could sacrifice for a case which might make it financially viable.

Hmmm...
 
If you have a low feedback design then ideally you should have a constant gain over the current range you are operating over. The onsemi Devices seem reasonable in this respect, they can handle the power and voltage with a good margin so should be reliable.
 
russel said:
If you have a low feedback design then ideally you should have a constant gain over the current range you are operating over. The onsemi Devices seem reasonable in this respect, they can handle the power and voltage with a good margin so should be reliable.
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That makes sense, thanks.

Are these comparable to the historical devices that people are usually hunting down for builds like this?
 
eastone said:
That makes sense, thanks.

Are these comparable to the historical devices that people are usually hunting down for builds like this?
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IIRC the original devices were meant for switching but they were most likely the best available at the time.
 
Me thinks there's gonna be some very disappointed folks getting 4% THD and or (very probably and!) only 2W output here. From my experience with this design I regard it as not possible without a bench of test gear and the knowledge of how to solve the issues found with it. Something like a Krell KSA50 is actually MUCH easier as so long as you don't cock it up it should work fine. With the Hiraga amp everything is really critical and each one that works as it should will be somewhat different from others EG where there is lets say a 2k2 resistor on the schematic it may well need to actually be anything from about 820R to 3k3 depending on the transistor it's connected to (no not the type of transistor... the actual sample you are using!) and this applies to many of the resistors in it. Without a distortion analyser, low distortion signal generator and oscilloscope everything you do will be pure guess work!

The one I did up thread was built with the designers recommended transistors (not that easy to get now) and still needed some of the resistors to be 100% out from the published values to get it to work to spec.
 
Arkless Electronics said:
Me thinks there's gonna be some very disappointed folks getting 4% THD and or (very probably and!) only 2W output here. From my experience with this design I regard it as not possible without a bench of test gear and the knowledge of how to solve the issues found with it. Something like a Krell KSA50 is actually MUCH easier as so long as you don't cock it up it should work fine. With the Hiraga amp everything is really critical and each one that works as it should will be somewhat different from others EG where there is lets say a 2k2 resistor on the schematic it may well need to actually be anything from about 820R to 3k3 depending on the transistor it's connected to (no not the type of transistor... the actual sample you are using!) and this applies to many of the resistors in it. Without a distortion analyser, low distortion signal generator and oscilloscope everything you do will be pure guess work!

The one I did up thread was built with the designers recommended transistors (not that easy to get now) and still needed some of the resistors to be 100% out from the published values to get it to work to spec.
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If I did one, I think I would be asking you to put it together Jez!
 
Arkless Electronics said:
Me thinks there's gonna be some very disappointed folks getting 4% THD and or (very probably and!) only 2W output here. From my experience with this design I regard it as not possible without a bench of test gear and the knowledge of how to solve the issues found with it. Something like a Krell KSA50 is actually MUCH easier as so long as you don't cock it up it should work fine. With the Hiraga amp everything is really critical and each one that works as it should will be somewhat different from others EG where there is lets say a 2k2 resistor on the schematic it may well need to actually be anything from about 820R to 3k3 depending on the transistor it's connected to (no not the type of transistor... the actual sample you are using!) and this applies to many of the resistors in it. Without a distortion analyser, low distortion signal generator and oscilloscope everything you do will be pure guess work!

The one I did up thread was built with the designers recommended transistors (not that easy to get now) and still needed some of the resistors to be 100% out from the published values to get it to work to spec.
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I use right mark audio software, cheap and does the job, there are probably others but this one is good enough for hobby use. I use a U24XL and for lowest noise use a laptop on battery power, although you could get plenty of useful information of the standard pc audio interface if funds are really tight.

https://audio.rightmark.org/index_new.shtml


https://www.esi-audio.com/products/u24xl/
 
russel said:
I use right mark audio software, cheap and does the job, there are probably others but this one is good enough for hobby use. I use a U24XL and for lowest noise use a laptop on battery power, although you could get plenty of useful information of the standard pc audio interface if funds are really tight.

https://audio.rightmark.org/index_new.shtml


https://www.esi-audio.com/products/u24xl/
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Yeah I guess in this day and age one could use a software solution with suitable audio interface for this task. A suitable "interface to the interface" is invaluable if doing so though as many PC audio interfaces can't handle much input voltage and could be damaged by overload. I believe there are DIY and probably pre assembled units offering input attenuator, protection diodes etc etc. Me? I'll take good quality analogue instruments every time!
 
I’ve had a clone/version of this amp sitting idle for quite a while now, I keep coming back to it. The kit came with the Sanyo transistors but I have since purchased a matched quad of the original transistors and I may even buy a matched quad of the most recent variants on-semi NJW0302G/NJW0281G just to listen to each version. The most recent additions are 1 dual rail CRC power supply per channel from Serbian hifi-stor each with 8 x 68’000uf caps. I now have to get the transformers and I’m thinking dual 9v secondaries at around 240va but I’m unsure? I’m also very worried that without a fully kitted out test bench I may never get it running optimally.

Matt
 
matthew franklin said:
I’ve had a clone/version of this amp sitting idle for quite a while now, I keep coming back to it. The kit came with the Sanyo transistors but I have since purchased a matched quad of the original transistors and I may even buy a matched quad of the most recent variants on-semi NJW0302G/NJW0281G just to listen to each version. The most recent additions are 1 dual rail CRC power supply per channel from Serbian hifi-stor each with 8 x 68’000uf caps. I now have to get the transformers and I’m thinking dual 9v secondaries at around 240va but I’m unsure? I’m also very worried that without a fully kitted out test bench I may never get it running optimally.

Matt
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I'd go for 12 0 12 secondaries. You will lose some in the "R" of the CRC... The 8 x 68,000uF per channel is great. Yes you will need a well equipped test bench to get it running properly...
 
How do I attach images these days? Flickr only gives me the option to copy url and if I attach that here it won’t let me post saying it contains spam?

In my limited understanding the circuit diagram looks as though it needs 2 x 9v + and - per channel not 9-0-9

I plan on having each channel as mono blocks in separate chassis.

Matt
 
matthew franklin said:
How do I attach images these days? Flickr only gives me the option to copy url and if I attach that here it won’t let me post saying it contains spam?

In my limited understanding the circuit diagram looks as though it needs 2 x 9v + and - per channel not 9-0-9

I plan on having each channel as mono blocks in separate chassis.

Matt
Click to expand...

To share from Flickr select the bent arrow share icon on the bottom right of the photo. Then from the window that pops up select BB Code and copy the URL that’s shown. Then paste the copied URL in your post - paste it directly, don’t use the image option in the editor.
 
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