Le Monstre vs. Parallel JLH class A?

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deicide67

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Joined 2008
#1
I'm still in the parts collection stage, but still up in the air regarding which of these designs to build. Can anyone offer subjective opinion on these designs? The JLH looks nice and uses 4 output devices so I would assume it dissipates heat a bit better. Plus it uses TO-3 devices which my sinks are already tapped for.

Le Monstre looks simpler, and I can alter my sinks to use the 2SC5200s. It claims 58w into 8 ohms rms while the JLH is only 28w into 8 ohms, but will double into 4 ohms at 56w.

What design would you guys reccommend? What are your impressions of the sound quality of these designs?

Thanks for any information on these! Also, what size transformer is reccommended for these?

Blair
 
#2
deicide67 said:
the JLH is only 28w into 8 ohms
Click to expand...

I wonder what your needs are for power - what kind of speakers (impedance, sensitivity) and how loud you want to go. I suspect that 28W is plenty of power for your needs and shouldn't be a factor in choosing between these options. Power dissipation might be a factor, the lower power of the JLH means less heat-sinking. I haven't heard either amplifier, but I have read many consistent good reports on the JLH and it would be my choice if I had to make it.
 
#3
Thank you! The JLH is the one I am more apt to build. Depending on what speakers I'm using they range from 4-8 ohm and are typically 87-90db efficient. I have used SET amps in my system many times and they are just shy of what I need in power at 12w. I purchased 80,000uf of capacitance during lunch along with TO-3 sockets and mica spacers. This should get me started on the layout for the monoblocks.

Thanks again!

Blair
 
#4
I'd be interesting to follow your progress. I've recently become a lot more interested in Class A amplifiers. I may start with something very simple (e.g. a single output transistor) to get my feet wet but if that turns out I'll be taking a good look at the JLH myself.

Your speaker sensitivity sounds fine. I'm not sure how well particular amps cope with 4ohm loads, but you have a chance to design to suit (e.g. more current flow perhaps) if you feel it needs it.

p.s. I discovered that you might be able to get a pcb: http://skycoral.com/1/?p=23
 
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#11
I did extensive research on pcbs for the jlh. you will not find them anywhere except at kk-pcbdesign.net

also, the pcbs on ebay are of modified (and supposedly updated) versions of the jlh. if i were you, i'd build the originals first.

on geoff moss' excellent jlh website, you will find dual rail versions of the 1969 version as well, which is obviously simpler than the 1996 version. It will eliminate the output cap.

i've ordered the chassis and trafo for the jlh. keep us updated on your build and i'll try to keep u up on mine.
 
#13
ra7 said:
I did extensive research on pcbs for the jlh. you will not find them anywhere except at kk-pcbdesign.net

also, the pcbs on ebay are of modified (and supposedly updated) versions of the jlh. if i were you, i'd build the originals first.

on geoff moss' excellent jlh website, you will find dual rail versions of the 1969 version as well, which is obviously simpler than the 1996 version. It will eliminate the output cap.

i've ordered the chassis and trafo for the jlh. keep us updated on your build and i'll try to keep u up on mine.
Click to expand...

Thanks,

The only issue with that board is that it is not the higher power version I'm looking for. The link provided to me earlier in this thread:

http://skycoral.com/1/?p=23

seems to be my best option as Geoff, the gentleman referenced on JLH's site supposidly assisted in the design process.

I'll keep you posted on my progress. I should be bolting a chassis together sometime withing the next week or two. I have a few amps and preamps to sell off first😱

Blair
 
#14
This is the Le Monstre circuite. The name came for the power supply which
was huge. I believe it used 2 80AH car batterys and a pair of 250.000uf caps.
 

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#15
Yes Woody,

The amplifier circuit I'm referencing is a variation on a variation of that circuit using higher power transistors. I believe it has an additional driver stage, but I'm no SS guy so I may be mistaken.

While the original Le Monstre and JLH look like simple and easy circuits to build, I'm looking for something with a little more power.

Thank you,

Blair
 
#17
Probably nothing of interest to many here on the SS forum.

A 12AU7 linestage, and a triode strapped 6550 amplifier. The linestage is a unity gain with a stepped attenuator running a fairly low B+ and regulated filaments. The 6550 amp is a choke input design using a 12AX7 VM, and 6CG7 PI circuit. Approximately 25w since my B+ is only 360V.

I have built a few LM3886 amps, but these seem more up my alley as far as what I've heard regarding SS amplifiers. I am also working on a pair of SKA 300Ds. TOO many projects and not enough time....

Eventually, I'll finish a small SE KT88 amplifier and sell it off as well. It is done for the most part, but not enough to sell. I'm supposedly trying to get out of this hobby😉

Blair
 
#19
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An externally hosted image should be here but it was not working when we last tested it.


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Yep, I stay really busy!! LOL!! Hopefully SS is just as fun!!

Blair
 
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