Stranger things have happened but I understand from his Wikipedia C.V. that he was in charge of the electronics lab. and research team at British Cellophane, from 1954, after several stints with various large authorities and corporations like G.E.C, - engaged in atomic energy and power generation projects, as it appears. I'd say if he needed components, he had them to hand with few questions.
I made this kit, no need to change anything, it's superb: https://jlh1969classa.blogspot.com/p/my-build.htmlI'd buy a kit rather than built as easier to change bits if needed eg
https://www.aliexpress.com/item/1005004603589147.html?spm=a2g0o.detail.1000014.3.574924d2DdYQAt&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40000.333919.0&scm_id=1007.40000.333919.0&scm-url=1007.40000.333919.0&pvid=c334262e-0aad-4f37-a431-bcbbd1094372&_t=gps-idcDetailBottomMoreOtherSeller,scm-url:1007.40000.333919.0,pvid:c334262e-0aad-4f37-a431-bcbbd1094372,tpp_buckets:668#2846#8113#655&pdp_npi=3@dis!GBP!13.19!9.1!!!!!@211b812f16834472037906269eaf94!12000029794591801!rec!GB
Cheers - J
Yes I also bought it.Hope will arrive soon.
I now have quad 405, Ta2020 and some other class d amps which are not necessary blameless clones, F5,aleph j and f5 turbo and Naim pcbs ,4pcs jlh mini amps and this Jlh kits .I think I should sell some of them to friends but I should find some enclosure solid cad files first Is there any in diyaudio? Some Perforated top and bottom cover files would be good.
I now have quad 405, Ta2020 and some other class d amps which are not necessary
blameless clones, F5,aleph j and f5 turbo and Naim pcbs ,4pcs jlh mini amps and this Jlh kits .I think I should sell some of them to friends but I should find some enclosure solid cad files first Is there any in diyaudio? Some Perforated top and bottom cover files would be good.Interesting comment on the heatsink. I'm pretty sure I recognise them. Around 4C/watt and easily available.
I may have some around but unfortunately others tidy things up now and again here over several years and it can be extremely difficult to find stuff again. Probably in an attic room that has had lots of other stuff crammed in. There wasn't all that much in there when my electronic bits went in. Now it's hard to even move around in there.Have you actually done any measurements on it? The kit I linked to included the heatsink.
I'd agree with you comments about temperature. The makers do not just invent the numbers. Toshiba though do qualify their specs on some of their power parts by referring to notes that I have never read rather than giving details in the data sheets. They appear to relate to more than one factor all at the same time.
it also existed at one time in a TO3/TO220 hybrid version which was very nice for testing
I don't see any serious problems with removing the transistors from the built version to make up a test jig. The kit saves around £1. Total cost less than the heatsink it's on assuming some one could find a source for it.
Measuring performance on the cheap via a pc and software does have a bit of a problem due to sampling rates. The bandwidth going in has to be limited or garbage can come out. What ever is used to do that can be tested with the same kit. The various interfaces that can be used may have something built in - who knows? I don't.
I think Huggygood is referring to live testing - critical listening over some days with a range of music program. That may seem a bit wobbly by comparison with formal, precise test bench methods but at the end of the day, what you hear in your listening room is the most important characteristic of your audio system.
Few of us on this thread seem to own or at least refer to PC based or any advanced type of test instrument. These tend to be rather expensive even though the insides aren't much more than a decent soundcard and this means it will likely be band limited to some inaudible harmonic of 20kHz. Focusrite Scarlett products seem to be popular and have relatively cheap interface boxes for this type of DIY testing but we have enjoyed some extensive reviews and tests here of what is now a 4th version of a good quality, dedicated audio test interface by Quantasylum (https://quantasylum.com/products/qa403-audio-analyzer). The first version, QA400, was extensively checked and reviewed here by some of our pro. members who know audio testing well enough to write books on it.
Few of us on this thread seem to own or at least refer to PC based or any advanced type of test instrument. These tend to be rather expensive even though the insides aren't much more than a decent soundcard and this means it will likely be band limited to some inaudible harmonic of 20kHz. Focusrite Scarlett products seem to be popular and have relatively cheap interface boxes for this type of DIY testing but we have enjoyed some extensive reviews and tests here of what is now a 4th version of a good quality, dedicated audio test interface by Quantasylum (https://quantasylum.com/products/qa403-audio-analyzer). The first version, QA400, was extensively checked and reviewed here by some of our pro. members who know audio testing well enough to write books on it.
Last edited:
"Listening over some days with a range of music program":
This time a difficult task for me, days of listening, getting used to it, since sonically tie: passive power supply, two rails (+ and -), two capacitors per rail versus one transistor each as "diode", or "regulation", between these two capacitors.
This time a difficult task for me, days of listening, getting used to it, since sonically tie: passive power supply, two rails (+ and -), two capacitors per rail versus one transistor each as "diode", or "regulation", between these two capacitors.
I've run soundblaster stuff on my PC's for a long time as they can make a big difference what ever speakers are on the end. This is a report on an earlier one than I have now also mine is USB. Rightmark is no longer supported but the only one I can run at the moment - under Linux via wine,
https://audio.rightmark.org/downloads/Sound Blaster X-Fi Testing Methodology And Results For RMAA v5.5.pdf
Mine appears to have a sharp roll over at 20k but there could be several reasons for that including the pc. In some ways it looks usable for testing but things like level meters are bound to need sorting out. So if I connect it's inputs to it's outputs to test the volume knob needs tweaking, If I had Creative software it may well account for this aspect. Otherwise the best option is probably hook up a scope. ESI do a unit that near indicates clipping. Bought before I realised I must have a USB mic. Not bothered testing it as feel I may as well wait until I can run REW. I need to update my OS to do that. Cost of the unit £58, It can provide phantom power to a mic. Some of their units cost more.
On the face of it people don't need to spend a fortune to test and I would feel the one you linked to is too expensive. Scopes. There are decent USB ones around and the real thing at various price levels. What I often see around on here is simulations not tests. It's testing that interests me. I can't see myself trying to duplicate the AV receiver we use in the lounge or going back to separates but who knows.
Suppose my comment on bandwidth and sampliing was down to a lack of specification on the units that can be used. If I buy anything else I'll probably ask about this area elsewhere on the forum. I'll post what the ESI unit does within the range I can test it. I do have various bits of kit around,What do you think about large capacitor bank on Jlh? Does it make bump at first switch on? I read it shortens speaker life. Smps make little bump. Or try regulator. I am decideless.
Just try everything - let your ear decide;-)
And: before a large capacitor bank comes first of all to find a good sounding capacitor. Before a regulator comes first of all to find good sounding active parts.
Just do it. These experiences no one will take away from you;-)
And: before a large capacitor bank comes first of all to find a good sounding capacitor. Before a regulator comes first of all to find good sounding active parts.
Just do it. These experiences no one will take away from you;-)
A technican friend told me that he listened to amplifier with gold plated power cable.And said that it made huge difference ,sound improved a lot.Maybe he forgot that apartment has poor wiring corrosion etc. LOL
The simple act of removing and reconnecting cables that haven't been cleaned or replaced in years may improve your sound too. Even someone with poor hearing can perceive the benefit of good connections, assuming that the existing ones are actually loose, corroded or otherwise impaired. Some of us seem unaware (or in denial) that replacing cheap but adequate cables with new, high grade stuff, may in effect be doing no more than could be done with a piece of cotton cloth.
Last edited: