Quite a few DMM's that are half decent type K thermocouple socket and temperature probe - if you wedge the probe in between 2 of the fins with a suitably sized piece of cable you can monitor easily over a long period.
Perhaps even better would be a temperature data logger with a thermocouple socket - this way you don't have to watch it constantly and you can download a permanent record to your PC.
I don't know about IR temperature reading.
Perhaps even better would be a temperature data logger with a thermocouple socket - this way you don't have to watch it constantly and you can download a permanent record to your PC.
I don't know about IR temperature reading.
P.S.
check this out:
eSecure - Digital Cooking Probe Thermometer for Food, Meat, BBQ, Turkey: Amazon.co.uk: Kitchen & Home
there are others also - some less than £5
check this out:
eSecure - Digital Cooking Probe Thermometer for Food, Meat, BBQ, Turkey: Amazon.co.uk: Kitchen & Home
there are others also - some less than £5
Thanks mikelm. Both useful. The other thing I thought about was one of those temp' sensing semi's bonded to each h/sink and a rotary switch (of the appropriate number) so as to switch each one to a single circuit/display unit. Bit like the old valve amp' voltage reading/monitoring system.
Cheers, J. To be continued...........
Cheers, J. To be continued...........
Correct, the cfp is only the least complex improvement he showed, not that the others are much more. There are more improvements that he shows in his book and I have another 2 sent to me via private contact when I was still a student. If you look at a sim youll notice how much closer the collector and emiter currents are when in cfp mode.
Where can I see the 2000 version ?? His design or someones mods ??
Im more curious is how others will like it, I played around with these circuits as a student more than 20 years ago. The last and best sounding was a circuit very similar that you see in SSA thread and in class A without feedback in output. This scheme was also developed with input from JLH to reduce high order harmonics, he was the original designer after all. Ive dumped all Class A design however, too much heat for so little improvement compared to well designed class AB.
The Class-A Amplifier Site - JLH Class-A Update
Maybe not 2000, but from around that time (I'm sure I've heard it referred to as that). Also, it's actually based on the '96. I knew what I meant!
Maybe not 2000, but from around that time (I'm sure I've heard it referred to as that). Also, it's actually based on the '96. I knew what I meant!
Which JLH book are you referring to?
I have 2nd edition, The art of Linear Electronics.
He only mentions the 15W ClassA '96 version from the Wireless World article and shows the 10W ClassA '69 version schematic.
There is no discussion of CFP, nor Liniac, nor any other modifications to his 69/96 ClassA amplifier.
I have 2nd edition, The art of Linear Electronics.
He only mentions the 15W ClassA '96 version from the Wireless World article and shows the 10W ClassA '69 version schematic.
There is no discussion of CFP, nor Liniac, nor any other modifications to his 69/96 ClassA amplifier.
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yeah, but you do live in one of the nicest and warmest countries my friend whereas I appreciate a bit of warmth in the winter.
Hi AndrewT,
I established earlier Homemodder's referring to The Art of Linear Electronics, I think p97, where JLH suggests a phase splitter can be improved (as it is essentially an emitter follower) by using a Darlington or a CFP. He also suggests other phase splitter arrangements on the next page (one similar to that in the Hiraga- if I recall).
So, a reasonable comment that JLH suggested it could be improved, however, I'm reluctant to change my JLH at the moment (I'm very happy with it as it is - and like the idea of keeping it as true to the original design as possible). Maybe one day I'll consider it for my next, very low powered, amp.
Also, I suppose it could be arguable that transistor choice could affect this stage as well (a good quality, high beta transistor (suitable for driving the output) of today could compare well to a CFP using components from 1969).
I established earlier Homemodder's referring to The Art of Linear Electronics, I think p97, where JLH suggests a phase splitter can be improved (as it is essentially an emitter follower) by using a Darlington or a CFP. He also suggests other phase splitter arrangements on the next page (one similar to that in the Hiraga- if I recall).
So, a reasonable comment that JLH suggested it could be improved, however, I'm reluctant to change my JLH at the moment (I'm very happy with it as it is - and like the idea of keeping it as true to the original design as possible). Maybe one day I'll consider it for my next, very low powered, amp.
Also, I suppose it could be arguable that transistor choice could affect this stage as well (a good quality, high beta transistor (suitable for driving the output) of today could compare well to a CFP using components from 1969).
I did not link the p97/98 info to the ClassA 10W/15W amplifiers, p166 to p168. JLH does not suggest in either location, that these be combined for an improved version.
Yes, it is reasonable to surmise that an improved version could be had and experiment could reveal the truth, but that would be Homemodder's extension to the JLH design, not JLH's suggestion.
Yes, it is reasonable to surmise that an improved version could be had and experiment could reveal the truth, but that would be Homemodder's extension to the JLH design, not JLH's suggestion.
No, actually his extension, if you want to learn anything from him you have to read between the lines, read all his published articles and youll notice he only guides you, and with hints on how to improve. With this design he starts just by saying what parameters to look for in the vas transistor, the rest you get the message from his book.
Dont you find it odd that he emphasized the phase splitter circuit so much in his book when its a circuit that vertually had disappeared from usage.
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It gets so hot here during summer your shoes rubber melts on the tar and you need three showers a day, believe me its not so nice, I havent been able to decide which is the worst, cold or the warm weather.
Cheers Kenneth
2 simple power supplies. Each has a 160VA transformer, bridge rectifier and as much capacitance as could fit in the case/budget.
Case:
Enclosure RE2107H 212x70x257 - Boards | Kits | Components | Modules | Tools
I love that small casing
I've built a 96 version in a bigger case. I was looking for a case that was smaller than 19" so I could build 2 monoblocks instead. Maybe this case could do. Did you build the 10w(69) or the 15w(96) version and is it really big enough to cool down the amp?I love that small casing
I made the 15W version - It does run hot, I can touch the heatsinks for 10 secs but with discomfort. Even though the external surcace gets quite warm the components on the inside are still quite cool after a couple of hours.
I just got my 69 jlh working tonight. I am using a standard crc PS and MJ15003 output devices. The sound quality of this amp is impressive but I have 2 small problems. The first is a small hum in one channel, I am sure I just need to double check my connections to fix it. The second is that I love pin point imaging and this amp doesn't currently have it. The amp has cheap chinese input caps, I am guessing this may be part of the problem. Does anyone have a good cap they can recommend for a replacement? I am looking for something under $10. I would also like to know if there is anything else I could do to improve the imaging of this amp.
