JLH '1969' Class A Amplifier Power Supply Build & Test

In this video, I build a kit that was designed as a suitable power supply plus muting relay system for the JLH "1969" amplifier modules. Unfortunately, the kit is no longer available as far as I can find.

[brendan]

Only just discovered your channel and love your work. You've answered many questions about audio electronics that I've been looking for and with an Aussie accent to boot

[marcinmetcalfe]

This video really helped me get the amplifier and power supply setup and provided me with a very good understanding of how the circuitry works. I also very much appreciate how you use relatively simple and inexpensive test equipment to set everything up. I have watched many of your other videos and I really like the way you explain things. You make it interesting and easy to understand. You’re a natural teacher and its great that you take the time to create drawings and schematics to explain. BTW, what is the “Shadows” like song playing at the end? Thanks again for taking the time to make this videos. (Like you sense of humour as well)

[gpasc]

Hi dear,
I am looking for a Class A/AB High-end amplifier to play bass-guitar (with a pre-amp plugged before it).
please wich one do you recomend?
The complet produt with all the boards, power supply, case-box, etc..
best regards,
Gabriel.

[JunPVlog]

Thank you for sharing sir new supporters here

[brandonburr]

I have had this jlh 1969 amp kit wired up and working with a giant aluminum slab of heatsink (guessing 10 to 15 lbs) with a acopian a28h1100 linear power supply for a while as a experiment. Sorta shocked even without its companion power supply what these cheap Chinese amps can do. I have seen some folks say some other amps are better ( no doubt their is always better in this hobby ) but these are really good for what they are. These have do right powering my large b&w 802 the way they do with $$$ dac and preamp. I thought this amp hasn't been given a fair shake and wanted to thank you for putting in the time to test one out. Be curious what you would do to improve its performance? I have seen more versions similar to this. Their is a jlh 2003 version as well. Curious to what other class a amps you would Try? Maybe a diy pass labs first watt f5, f6, or a aleph j? Been wanting to try a aleph j for a while based on all the positive feedback. Been collecting parts for a while and have the f6 parts kit (they always sell out!) And the parts for a àleph j. I thought since so many folks have make these, or going to make one it would be some good material for your channel. You could do the power supply boards and build up (it's the same for all first watt amps so you can reuse it and exchange input boards). Than you can do another in stuffing one of these input boards and testing with a power supply. Or perhaps you could start with one of Nelsons class a amp camp 1.6 amps (2 kits for monoblocks) . These kits also sell out at diy audio. Just throwing out ideas for ya! Thank you again!

[gabrielomar]

Hi....I have the same kit as yours jlh 1969 and I wanted to know ... you the two blue trimmers at what value did you set them ?? your psu where can I find the files to make the pcb then ?? a thousand thanks...congratulations for the video!!! 👍👍👍

[robertjc]

Another great video, I'm learning a lot by watching your videos. I'm not a electronics expert so I need to ask a couple of questions. I'm planning on running two of these amp boards for stereo, do I need to get a transformer with a centre tap and if I use a 24v transformer and go through a power supply board with a 4 diod rectifier will that increase or decrease the voltage by enough to worry me or the amps.

[hanshase]

Hello, I also built the power amplifiers, but I have problems with the power supply. The ones you're using don't exist anymore, what could I use? Can't find a solution and nobody can tell me anything. Can you help me with that. Would be really grateful to you, I'm desperate. Very good video. Greetings from Germany

[asharahmadarrauf]

Is regulated psu necessary for jlh1969.

[kernalkorn]

BOOM! 100 Amps Current-ly Liking! Oh God Almigh-ty!

[thecheapaudioengineer]

The way it is done is reversed normally


Normally open contact is in the output of the amp.

Then normally closed is grounded.

And the common is connected to the speakers

That way the speaker is protected.. it also does not destroy the relay.. ...

[utsavprakash]

I have a transformer 18-0-18, 5 A. Will it work for 2 boards (Stereo), If I am using same centre tapped full wave rectifier? What is the minimum capacitor bank required for this ? Thanks !

[joe_wattimena]

what is the wattage of the speaker...???

[patrickfendt]

to make a stereo amplifier you need 2 amplifier 1969. Do you also need 2 power supply card or just one is enough? and if you need 2 power supply card what transformer power should you use. thank you in advance. Patrick

[Theineluctable_SOME_CANT]

You don't understand a dethump circuit!

Unsubbed.

[robertjc]

Hi, because chinglish is hard to understand could you please tell me exactly where you connect the multimeter to adjust the voltage and current. Your help would be much appreciated.