Hiraga "Le Monstre"

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#1,381
le Monstre ( Jean Hiraga ) compared to Amp Camp Amp ( Nelson Pass )

Hello out there


I was wondering if anyone had anything to say about the comparison between the Jean Hiraga le Monstre amp and the Amp Camp Amp from Nelson Pass.
The reason why I´m asking is that I have always wanted to build a le Monstre , but my knowledge about DIY electronics is not sufficient enough to build such an amp.


I was also wondering if anyone here has built the Amp Camp Amp from Nelson Pass and had the opportunity to compare these two amps.


* I have understood that the le Monstre is built with a larger / often complicated / and expensive PSU. But the le Monstre amp itself is a "simple and elegant" amp like the initial thought behind the ACA from Nelson Pass.​


I hope to hear thoughts from someone out there to tell about similarities / differences between these two amplifiers.

Thank you!



Ref to the Amp Camp Amp :
http://www.firstwatt.com/pdf/art_amp_camp_1.pdf
 
#1,382
Hi
We have built ACA and also Hiraga. Both amps are very good, but Hiraga has better highs and clear midrange, also more gain. AMP camp is very good. i am still using it with my vintage University speakers, but Hiraga is better by good margin.

Regards
Sachin
 
#1,384
tralalalala said:
Hello out there
I was wondering if anyone had anything to say about the comparison between the Jean Hiraga le Monstre amp and the Amp Camp Amp from Nelson Pass.
]
Click to expand...

I built the AmpCampAmp and later the Le Monstre with original transistors from the 15W kit from ebay Hongkong (I also tried new transistor replacement board but this sounds worse and has less gain)

I did not like the AmpCampCamp on my Fostex Full range speakers, it sounded quite a bit worse in dynamics and high notes than a miniwatt tube amp. The Le Monstre with original transistors is a much nicer sounding amp (sounding also more precise than the miniwatt tube amp), and I have since dismantled the AmpCampAmp. To be fair I did not use the original US components but similar European components from Reichelt (resistors for example are different, and had more inductance) and built on a circuit board by point to point wiring. This may have contributed to my versions of the AmpCamp not being quite as good as the original. I probably would not bother with the AmpCampAmp again, but instead directly reproduce a well known amp like the LeMonstre or a bigger Pass amp. One mistake I made in the beginning was that I thought I was clever and could alter the design of the power supply a bit, as long as I overbuilt. Now the Le Monstre is almost too heavy to lift and has some stupid choice of components in it (cheap comonents later had to be replaced, so I should directly have bought the proper component, such as input filter etc). As a beginner, I would now follow a build example exactly and not change anything.

Other amps I have built since are a LM3886 and Hypex class D amp - these projects are much easier because the boards are ready and the sound is very nice and clean (the le Monstre is not as clean, but the distortion "dirt" actually is nice sounding, as for example with tube amps).
 
#1,388
If the power transistors are really soldered on the board as it looks mounting them to a heatsink will be a tough task. Also mounting holes are omitted (as often seen, why oh why?) making mounting them possible with melt glue or the like. Please add m3 mounting holes and use M3 standoffs for proper mounting the board.
 
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#1,390
How ? They are faced opposite which makes thing complicated AND there are no holes for using a screw driver to tighten them to the heatsink (if you mean to mount them on a heatsink under the board). I suppose you will not really wire them 😉

* Normally holes are included to put a screw driver through the hole to tighten the transistor. I don't see an easy possibility here. Check the VSSA by Jason Kueteman to see what I mean. Please note that better decisions now make building the device way easier.

http://www.diyaudio.com/forums/group-buys/251782-vssa-through-hole-version-jason.html

You could include rectifier diodes as almost everything already is on the PCB. makes wiring easier and has no drawbacks. Complete board if you do. It has no real benefit using chassis mount rectifiers bridges when caps are on the board.
 
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#1,391
I mean, i will not directly solder the transistors pins to the PCB. I want to "extend" the pins with appropriate cables, so that i can use my current heatsink, since there is no way i could design a PCB that would allow me to directly solder the pins into it, and also use my current heatsink.
 
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#1,392
Please don't use this method. If you bend the pins of the power transistors upwards and adapt the PCB design AND add those holes you can solder those transistors easily to a flat surface heatsink. Extending lead wires is asking for trouble. I like your design and i would make it a stereo board and add speaker protection by means of a relay. Learnt my lessons with hot amps. Always costs you a woofer when it breaks down. A speaker relay with heavy duty silver contacts and a uPC1237 cost way less 🙂 If you leave it like it is you will be greeted by your woofers saying hello when you switch this amp on.
 
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#1,393
Then i would have to buy a thick (~0.8cm) aluminium sheet, and bend it into an 'L' shape. Also, my power transistors are in TO3 packages. Yes, i've been thinking about building speaker protection, however i'm a member of the modular PCB comittee, because i'm on a tight budget, and i would also like to try different amps, preamps, DACs, hence, i want to keep things slightly modular.
 
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#1,394
You sure like to make life complicated 😀 I think you don't understand what I mean. Most new designs have the PCB mounted on the heatsink and use 4 standoffs and "flipped" transistors for way easier mounting. That way one does not need special heatsink but simple a large chunk of aluminium with fins at the other side. Also no need for an L profile (except when using TO3, maybe). Flat packs ware way easier to mount and you already have a near ready design. Flip those transistors to the same direction, add the holes and you will be able to use more modern transistors. Won't make a difference when you use TO3 but will make a large difference when you build another one with flat packs. Costs you half an hour max.
 

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#1,395
I want to use the 2SC1116 and 2SA747 because they're original SanKen transistors, and they sound far better than standard TIP3055s. I like them, they were in a Marantz amplifier before, with the heatsink, if i'm correct. I have a stereo Le Monstre 8W with a slightly modded Philips CD player utilising a TDA1543 NOS DAC, and a pair of T+A Criterion T100s. I like the sound of the current system, hence, i want to keep everything, i only want to replace the proto PCBs with a better one, that also includes the power supply.
 
#1,396
If you make those changes you stil can use the stuff you want to reuse AND you will be able to use other transistors. Added benefit for 0 $.

BTW I have never seen a Le Monstre with 2N3055 ?!?

neptunes4you said:
Yes, i've been thinking about building speaker protection, however I'm a member of the modular PCB comittee, because I'm on a tight budget, and I would also like to try different amps, preamps, DACs, hence, I want to keep things slightly modular.
Click to expand...

Non modular you mean (when looking at the board) ? It takes one to know one 😉 You're on the right track padawan. Still adding rectifier diodes would make the PCB truly according our religion.
 
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#1,398
IF you use a buffer or preamp with Le Monstre you could add pads for an RC input filter. Better safe than sorry. If there will be a volume control straight at the input add the RC filter "before" that volume control. I know I am old fashioned but I always use coupling caps at inputs of DC coupled amps. Just because I can. Also because I used DC coupled amps since the eighties and have more than once burned my fingers with DC carrying sources. At least adding the pads gives the possibility to use them (or use a jumper wire). Just pads for a 5/10 mm film cap (3 pads per cap to make it possible to use different types) in each channel. When you are at it please add some decoupling film caps too at the rails as was done in the original Le Monstre.

Think about those diodes too. The smaller the loop the less possible troubles.

Psst ! Have a look here:

http://www.lencoheaven.net/forum/index.php?topic=20446.0
 
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#1,400
You did not understand what I meant. If you would have rotated the left or right PSU and power transistors (so only both the left or both the right) you could have used flatpack transistors combined with more easy mounting to a heatsink. Of course you would have needed holes for tightening the flatpacks too. You would have used wires to the TO3 anyway but it would have made it possible to change over to more recent flatpacks. It would have made it possible to try both TO3 and flatpacks so you could have compared etc. Now the design is TO3 only so now it is less flexible in transistor choice... Apart from that a Nice board but the old one was OK too. You added decoupling caps to the rails which is good.

When you will only use TO3 the new design obviously is a better choice. I always liked those sturdy TO3 transistors but hated the mounting 🙂 The need for special parts and the mica sheet with heat transfer paste. Yuk ! 😉
 
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