JLH 10 Watt class A amplifier

[Mooly]

The original version is great. Very good sound that is hard to beat even today.

 

[blu_glo]

Yes indeed it is; It was the first JLH class A design I saw and I built it with no problems whatsoever on veroboard!

 

[mosfetDemon]

I've built several JLH69s, and JLH96s on veroboard, and have never had a problem.
These amps are terrific for beginners; you can literally just lash them together and they work.

 

[btesize]

Hello I found JLH 2003 ver. pcb on ebay. 4 output transistor
probably more than power JLH 69.
have any information about JLH2003 or schematic ?

Thank you all.

Pure Class A OCL Sepp Amplifier Bare PCB JLH 2003 | eBay

 

[jfetter]

liquid cooling ?

 

[AndrewT]

Hello I found JLH 2003 ver. pcb on ebay. 4 output transistor
probably more than power JLH 69.
have any information about JLH2003 or schematic ?

Thank you all.

Pure Class A OCL Sepp Amplifier Bare PCB JLH 2003 | eBay

Ask the Retailer for some Customer Support.

 

[balle123]

Jims audio on ebay provide good support and schematic om jlh 2003

 

[jfetter]

Got the idea to use a tube instead of BJT at the input. In order to make it work all semis has to be PNP.

The first amp i diyed was the 2N3055-version and I loved it!

Did you build the hybrid?

Im doing something similar to jlh but with 12au7 and resistor loading. no ccs

 

[sensai]

I built my JLH 69s back in mid 90s (two monos), been driving els 57s very well and now els 63s, pushing it somewhat with these but as good if not better than an upgraded Audio Innovations (EL 34) 800 mk 1 that I have.

 

[saikatbiswas82]

Could anyone please let me know how does jlh perform with smps power supply?
I have already purchased jlh assembled kit from Jim's Audio. As per jim, the kit requires +33v. Now I am thinking about connexelectronic 300 smps with 30v output rail.

http://connexelectronic.com/product...ucts_id/128?osCsid=o5bk9v9mv2uhvhm9h3c99buea5

Will that be fine or should I go for linear psu with 22v transformer?

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[cumbb]

Active psu is a good thing. 30 V or 36 V in your case, or more, runs without problems.
Use ONE psu for both amps. Higher the capacity at the amps. The ear does give thanks for it.
My mind,-)

 

[saikatbiswas82]

Thanks cumbb. So, are you suggesting smps over lpsu for jlh 69?
One more thing. Is it better to go for 2x300w smps instead of 1x600w smps?

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[cumbb]

Tzzz.
Ipsu you mean trafo, rectifier, caps? Not more? Than I would prefer your smps.
1 x 300 W smps I would use. NOT 2 x 300 W. If sound channel-separate psu "better" than one, higher the quality of speakers, sources, room ...

 

[minek123]

Could anyone please let me know how does jlh perform with smps power supply?
I have already purchased jlh assembled kit from Jim's Audio. As per jim, the kit requires +33v. Now I am thinking about connexelectronic 300 smps with 30v output rail.
Connexelectronic
Will that be fine or should I go for linear psu with 22v transformer?

I would recommend SMPS from Sami (www.diysmps.com)
at info@diysmps.com
His SMPSes are really good for audio. I'm using his products in my amps.

 

[saikatbiswas82]

Ipsu you mean trafo, rectifier, caps? Not more?

Yes. I was trying to mean trafo, rectifier and crc filter. Nothing more. Not a cap multiplier.
Thanks again. Will go for single 300 w smps only. I will invest more on my upcoming OB project instead.

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[cumbb]

What an OB,-?

 

[saikatbiswas82]

What an OB,-?

Open baffle speakers

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[cumbb]

Not easy, but possible. I love the clean, clear "bass". Much much better than every "closed" rumbling, roaring wooden box,-)
Necessary to use a very good amp! Like a JLH,-!

 

[saikatbiswas82]

Not easy, but possible. I love the clean, clear "bass". Much much better than every "closed" rumbling, roaring wooden box,-)
Necessary to use a very good amp! Like a JLH,-!

Thanks. You just boosted my confidence.
I'm planning to drive a pair of full range speakers with jlh. I'm thinking about a pair of subwoofer drivers to be driven by class d amps. All in active xo configuration.

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[cumbb]

C-:
My mind: I would avoid a separate sub with separate amps. Except you want listen very very loud.
I would use bigger fullrange, 12" as example, and modify and damp these.
If separate subs, place behind or, if there no place, very close the monitors, to cover, or to get no direction of, the rumbling and resonating sound of the sub-casings. To get not separate sound.
My mind.-)