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JLH Headphone Amp
JLH Headphone Amp
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Old 26th January 2018, 03:51 AM   #741
wushuliu is offline wushuliu  United States
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Quote:
Originally Posted by ammel68 View Post
Why would you even buy that particular kit that uses a large output coupling cap and comes with such goofy "instructions"??

Most people, including myself, go with this kit or something similar:
GZLOZONE JLH HOOD1969 Class A Headphone amplifier Kit / Pre-amplifier Kit | eBay
Best $20 I've spent.
Oh boy - responses like that are why I spend less and less time on forums. I bought it because it uses a single rail supply, of which I already possess several so I don't need to mess around with a bulky enclosure and transformer and dc servo mods, etc. Unless I'm mistaken the large coupling cap is a prerequisite for the single supply design, as mentioned by the OP, ashok, in the early pages of this thread (the performance of which he mentioned as close to the dual supply you are talking about). As for the instructions, I've figured them out for myself, so I don't have anything further to say about this.
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Old 26th January 2018, 04:08 AM   #742
ammel68 is offline ammel68  United States
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JLH Headphone Amp
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Originally Posted by wushuliu View Post
Oh boy - responses like that are why I spend less and less time on forums. I bought it because it uses a single rail supply, of which I already possess several so I don't need to mess around with a bulky enclosure and transformer and dc servo mods, etc. As for the instructions, I've figured them out for myself, so I don't have anything further to say about this.
Fair enough. Actually, I didn't pay any attention to the single rail supply of that kit or the size of the board since so many other HA designs typically use dual rail supplies.

If responses like mine easily offend you, then perhaps you should spend less and less time on forums.
I was only curious why you had purchased that particular kit instead of one of the more popular ZERO ZONE kits.

Last edited by ammel68; 26th January 2018 at 04:16 AM. Reason: Spelling error.
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Old 12th February 2018, 03:51 PM   #743
wushuliu is offline wushuliu  United States
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Originally Posted by randomlf View Post
Just to follow up for posterity: I've replaced almost every cap on this board with good results. But the best mod was replacing the transistors with equivalent from Digikey. Maybe the ones it comes with are fake? At any rate, this amp now sounds really terrific. Even better after using a an LM317 to low noise LT3045 for 15v power supply.

A really nice, compact, cheaper option that allows greater flexibility with power supply with a couple simple mods. And based on what I can tell from the JLH single-ended schematic, this amp is very similar.
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Old 13th February 2018, 04:29 AM   #744
ammel68 is offline ammel68  United States
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JLH Headphone Amp
Glad to hear that you're pleased with the final results after replacing all the caps as well as all the transistors with transistors from DigiKey.

I've never found a LM317 to surpass the performance of a LT3045. Perhaps the off-the-wall single supply JLH circuit that you're using is some type of exception.
I've thrown all my LM317/337 supplies in the trash where they belong since they simply aren't up to the task of removing noise in higher gain applications, plus there are MUCHO better regulators out there.
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Old 13th February 2018, 04:34 AM   #745
Ricren is offline Ricren
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Originally Posted by ammel68 View Post
.
I've thrown all my LM317/337 supplies in the trash where they belong since they simply aren't up to the task of removing noise in higher gain applications, plus there are MUCHO better regulators out there.
Interesting. Would you care to mention a better replacement for an LM317? Thanks.
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Old 13th February 2018, 05:05 AM   #746
wushuliu is offline wushuliu  United States
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Originally Posted by ammel68 View Post
Glad to hear that you're pleased with the final results after replacing all the caps as well as all the transistors with transistors from DigiKey.

I've never found a LM317 to surpass the performance of a LT3045. Perhaps the off-the-wall single supply JLH circuit that you're using is some type of exception.
I've thrown all my LM317/337 supplies in the trash where they belong since they simply aren't up to the task of removing noise in higher gain applications, plus there are MUCHO better regulators out there.
I said I am using the LM317 TO the LT3045, not replacing. LM317--->LT3045--->headamp.

You've tossed your Salas headamp in the trash, LM317 in the trash. Forgot what else you've said you've tossed in the trash. Shame. Would be better off putting them up for sale to maybe benefit someone else...
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Old 13th February 2018, 07:26 AM   #747
jean-paul is offline jean-paul  Netherlands
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LT3045 is THE replacement for LM317. LM317 can be of good use as prereg but I would not use it as main regulator anymore. It still is used by many as it is the ECC83 of regulators. People simply often have the habit to use what they know, not what is best. Then they try to improve performance with tricks.

LT3045 does not need tricks. A truly excellent regulator. I just wish a 1.5A version and a negative version would be made.

Cheap way of trying it out can be with this PCB that uses its brother LT3042. It can deliver 1.5A but it is not short-circuit proof.

Low Noise LT3042 Linear Regulator Power Supply Module For Amanero XMOS DAC Power | eBay
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Last edited by jean-paul; 13th February 2018 at 07:33 AM.
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Old 13th February 2018, 05:18 PM   #748
wushuliu is offline wushuliu  United States
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Originally Posted by jean-paul View Post
LT3045 is THE replacement for LM317. LM317 can be of good use as prereg but I would not use it as main regulator anymore. It still is used by many as it is the ECC83 of regulators. People simply often have the habit to use what they know, not what is best. Then they try to improve performance with tricks.

LT3045 does not need tricks. A truly excellent regulator. I just wish a 1.5A version and a negative version would be made.

Cheap way of trying it out can be with this PCB that uses its brother LT3042. It can deliver 1.5A but it is not short-circuit proof.

Low Noise LT3042 Linear Regulator Power Supply Module For Amanero XMOS DAC Power | eBay
Yes, I love the LTs. The 317 was what I had laying around. Noise floor dropped like a stone once I added the LT.
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Old 6th March 2018, 09:23 PM   #749
Detectit1 is offline Detectit1
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Originally Posted by ammel68 View Post
Why would you even buy that particular kit that uses a large output coupling cap and comes with such goofy "instructions"??

Most people, including myself, go with this kit or something similar:
GZLOZONE JLH HOOD1969 Class A Headphone amplifier Kit / Pre-amplifier Kit | eBay
Best $20 I've spent.
Building this one... Almost finished... But can someone give me some instructions on the trimpots?
Where you measure?

Also it says 12V AC.. Think 15V also would be possible?
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Old 6th March 2018, 10:22 PM   #750
solder slinger24 is offline solder slinger24  United States
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The trimpots theoretically control the DC offset at the outputs.

In the real word offset varies widely depending on the temperature of the output devices.

Having assembled 4 of these JLH HA kits, IMO a servo is the only to really control the offset of these amps.

You could use 15V, but the regulators will get even warmer than they do using 12V.
Even with 12V the regulators' heatsinks get pretty hot.
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