Jokes aside ... looks like some serious mods there with some nice components, does it still work ? it would be great to make a couple of new monoblock amplifiers as I still think this is one of the best amplifiers I have ever heard . and that's being honest
Yes it still works (this was after extensive cleaning and fluff/dust removal) - or did until one of the amp boards malfunctioned.
I want to rebuild it so that it regains its former reliability.
Let me know about the boards?
Many thanks.
I want to rebuild it so that it regains its former reliability.
Let me know about the boards?
Many thanks.
Another Hart Kit builder
Hi!
I built a stereo amp back in the day when I used to subscribe to ETI magazine. In the end, one of my good friends at the time asked me to make two monoblocks for him.
After a year or so he got a local HiFi shop to bring around some components to do an 'upgrade' including some Roksan speakers and the conclusion was that he would have to spend a lot ( if I remember correctly 10k on amplification ) to do better than those monoblocks.
I am now thinking about building 4 monoblocks and bi-amping my TDL TRL3's as a project and I already managed to buy a couple of PCB's from someone in these forums a few years back, but with busy life they have sat in a padded postage bag for the last few years.
I wonder if it would be OK to get a company to 're-create' these PCB's from the original Amp and PSU ones I have?
Also, I need to do a bit of reading to try and work out if much has changed since the PCB's I have ( which I believe are the Hart Electronics ones ) before I think about sourcing components.
I am pleasantly surprised to see that peops are still discussing this design after all this time, as my memories of it are great - at the time I was using it with Mission 700 series and then with Celestion SL6S ( with updated crossover caps ( solex polys )).
Just hope there is still enough access to similar components to be able to build and test some.
Thanks
Hi!
I built a stereo amp back in the day when I used to subscribe to ETI magazine. In the end, one of my good friends at the time asked me to make two monoblocks for him.
After a year or so he got a local HiFi shop to bring around some components to do an 'upgrade' including some Roksan speakers and the conclusion was that he would have to spend a lot ( if I remember correctly 10k on amplification ) to do better than those monoblocks.
I am now thinking about building 4 monoblocks and bi-amping my TDL TRL3's as a project and I already managed to buy a couple of PCB's from someone in these forums a few years back, but with busy life they have sat in a padded postage bag for the last few years.
I wonder if it would be OK to get a company to 're-create' these PCB's from the original Amp and PSU ones I have?
Also, I need to do a bit of reading to try and work out if much has changed since the PCB's I have ( which I believe are the Hart Electronics ones ) before I think about sourcing components.
I am pleasantly surprised to see that peops are still discussing this design after all this time, as my memories of it are great - at the time I was using it with Mission 700 series and then with Celestion SL6S ( with updated crossover caps ( solex polys )).
Just hope there is still enough access to similar components to be able to build and test some.
Thanks
Hi Jamesfeline
please let me know a set of PCB's for amplifier/power supply that you can spare - to be shipped to US. Will be happy to work on this as i have built Cassette Deck kit of William Hart 2 decades ago
kannan
Hello ..
I can still produce these PCBs as I have created full gerber files for the originals .. happy to supply at cost price and to cover the cost of the PCB manufacture
I can still produce these PCBs as I have created full gerber files for the originals .. happy to supply at cost price and to cover the cost of the PCB manufacture
Hart Electronics 80w mosfet Amp construction manual
Hi
Can anybody help me with a Hart Electronics Construction Manual in pdf format of the John L Hood 80W mosfet power amplifier.
Desperately need it.
2 in 1
Hi
Can anybody help me with a Hart Electronics Construction Manual in pdf format of the John L Hood 80W mosfet power amplifier.
Desperately need it.
2 in 1
JHL 80W Mosfet
Hi jamesfeline
Can you perhaps tell me if the May 1989 ETI article of the 80W mosfet amp is without mistakes. Seen you have built quite anumber of the amps. I do have facilities to design and make my own pc boards. Hope I can still find most of the components. Replacements ?
2 in 1
Hi jamesfeline
Can you perhaps tell me if the May 1989 ETI article of the 80W mosfet amp is without mistakes. Seen you have built quite anumber of the amps. I do have facilities to design and make my own pc boards. Hope I can still find most of the components. Replacements ?
2 in 1
Hello
I do have the instructions but no access to a scanner at the moment, I will have PCB's available soon .. all parts are still available as I have all the hard to find transistors if you wanted to make as original as close as possible .. so watch this space I will be in contact soon .. keep safe regards
OK...back again with an update on my JLH Monoblocks project!!
Finally got a matching pair of transformers from Tiger-Toroids here in the UK.
Replaced all the electrolytics....and here in my solitude, am finally getting onto the last stage of getting these babies goin' again.....OR so I thought!!😱
Setting up the 50/55v rails on the PSUs, went swimmingly...until I got to the final -55v setting on one of the monoblocks! Essentially, adjusting RV4 does nothing...voltage continues to read 70v approx....so some work to do here.
Post #6 of this thread has the relevant circuit diagram (from Paul Kemble's page I think!)
Any thoughts out there on my next step please?? 🙂
Finally got a matching pair of transformers from Tiger-Toroids here in the UK.
Replaced all the electrolytics....and here in my solitude, am finally getting onto the last stage of getting these babies goin' again.....OR so I thought!!😱
Setting up the 50/55v rails on the PSUs, went swimmingly...until I got to the final -55v setting on one of the monoblocks! Essentially, adjusting RV4 does nothing...voltage continues to read 70v approx....so some work to do here.
Post #6 of this thread has the relevant circuit diagram (from Paul Kemble's page I think!)
Any thoughts out there on my next step please?? 🙂
Hello
sometimes you may have to put a small load on the power supply to set up probably I use a couple of low current lamps or load resistors to give the PSU some load .. assuming no faults of course
sometimes you may have to put a small load on the power supply to set up probably I use a couple of low current lamps or load resistors to give the PSU some load .. assuming no faults of course
Aaaagghhh....read about this in the manual...but didn't realise just how the failure of the rail setup 'manifested' itself!!
So...could be that it's going to be a simple fix.....here's hoping!!
Thanks James🙂
OK...got some advice on putting a small load on the PSU..tried it with a 3k load.and...still the same unfortunately...so I have another problem it seems 🙁
PSU Boards....
Hi James
...please let me know what a couple of your PSU boards would set me back!?
I'm messing with an 1150 and an 1150-2...so not exactly a 'pair'.
Does your board also include any of the 'mods' that are mentioned in the 'modifying' thread that is also on the forum pages??
Might be a nice project in my continuing isolation. 🙂
Thanks
Hi James
...please let me know what a couple of your PSU boards would set me back!?
I'm messing with an 1150 and an 1150-2...so not exactly a 'pair'.
Does your board also include any of the 'mods' that are mentioned in the 'modifying' thread that is also on the forum pages??
Might be a nice project in my continuing isolation. 🙂
Thanks
Hart construction manual for JLH 80w Mosfet
I can provide Hart construction manual if anyone is still interested. Plus I have original articles. I kept everything. Have 1996 class A plus 1989 Mosfet. Great sounding amps. Have compared to expensive commercial amps but I still prefer the Mosfet.
I can provide Hart construction manual if anyone is still interested. Plus I have original articles. I kept everything. Have 1996 class A plus 1989 Mosfet. Great sounding amps. Have compared to expensive commercial amps but I still prefer the Mosfet.
Hello Jamesfeline,
Do you have maybe a pair of PCB for sale? I have a bunch of K135/J50 selected pairs and would like to make use of them. 😀
Do you have maybe a pair of PCB for sale? I have a bunch of K135/J50 selected pairs and would like to make use of them. 😀
Hi Jamesfeline, I think you messaged me by mistake. I am not after any circuit boards. Didyman is.