|
Post by dean0 on May 12, 2009 15:13:31 GMT
My kit arrived today, psu, amp board and transformer Currentley reading through the threads to decide on mods, in a nutshell what do i need to do, get best out of this amp. thanks guys
|
|
Will
Been here a while!
Ribena abuser!
Member since 2008
Posts: 2,164
|
Post by Will on May 12, 2009 18:11:25 GMT
Hi dean0, This thread here rockgrotto.proboards.com/index.cgi?board=chitchat&action=display&thread=3622 has all the mods in one place. There are a few ways to skin the beast, with Alex's being the most used, and Robertkd's version being different again. If you are into Lost, you could consider one to be a Man of Faith, the other a Man of Science. You guess is as good as mine as to who is which!! I went the Alex (Sandyk) way, and have been massively pleased with the results. I really would suggest that you do each improvement a step at a time, starting from stock. JLH PSRR boards are available in the Components/For Sale section of the main forum, from a couple of sources, depending on your global location. Enjoy yourself, it's a great amp!
|
|
|
Post by dean0 on May 12, 2009 19:28:44 GMT
thanks, yes building from stock 1st, ive heard alot about the 'JLH PSRR', what is it for? thanks again
|
|
Will
Been here a while!
Ribena abuser!
Member since 2008
Posts: 2,164
|
Post by Will on May 12, 2009 19:52:29 GMT
Basically, it reduces noise on the supply rails to the amp to a extremely low level, so the noise does not effect the sound so much. It does other stuff as well, but it depends on how technical you want to get!
It really is needed to get the very best out of the LM4562, I feel.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on May 12, 2009 21:15:29 GMT
Basically, it reduces noise on the supply rails to the amp to a extremely low level, so the noise does not effect the sound so much. It does other stuff as well, but it depends on how technical you want to get! It really is needed to get the very best out of the LM4562, I feel. I don't doubt that Rick's and Robert's more extensive changes will lead to similar improvements with the SC HA when using the LM4562HA, as will other more expensive shunt regulators. A normal voltage specific dual polarity shunt regulator would be a great deal more expensive to build, as well as source all the components required. However, for ease of construction by the average person, the JLH version is much easier, as it simply goes in line between the voltage regulators and the actual HA PCB, without any major surgery being needed on the main PCB. To me, that was a major consideration when it came to ease of construction, (combined with good performance) by the average constructor, as well as those new to building amplifiers. Alex
|
|
|
Post by dean0 on May 20, 2009 11:51:47 GMT
Small Update PSRR board etched ready for parts Transformer mounted, and boards, waiting for parts Would like someone to double check the wiring on the transformer plz more updates soon
|
|
robertkd
Been here a while!
Electronics Engineer from sunny Queensland
Posts: 111
|
Post by robertkd on May 20, 2009 12:11:39 GMT
Small Update PSRR board etched ready for parts Transformer mounted, and boards, waiting for parts Would like someone to double check the wiring on the transformer plz more updates soon Dean0 looking good as far as i can see. I take it your going to cover the exposed "active" interconnect on the IEC socket up with some insulating tape? Whats the device adjacent to the IEC a thermal or magnetic cutout?? Looks like you have done the earth connection to the chassis quite proud looking forward to more piccys Robert
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on May 20, 2009 12:24:57 GMT
Robert I would imagine that it is an on/off switch. The interconnecting strip is alive at all times, so as you said , it needs to be insulated for safety reasons. I am looking forward to the next series of photos too. Alex
DeanO You seem to be using an earlier JLH artwork for the JLH from Canjunkie. On the bottom RHS of the photo, there is a missing bit of copper. This can be rectified by not cutting short the inserted resistor's lead, and bending it across to the left to replace the missing copper track. Please post some good quality photos of the JLH before you power it up, as there were a few errors in some of CJ's artwork, around the orientation of the BC550C and BC560C transistor locations. I would suggest that you do not solder in, or cut the leads of the BC550Cs and BC560Cs initially, just bend them underneath to stop them falling out, and then post a few photos so that we can check them for you, to help prevent possible damage. Alex
|
|
|
Post by dean0 on May 20, 2009 12:39:33 GMT
thanks guys, i'll tape that terminal asap, the device next to the iec is on/off switch.
What about the rest of the wires? what goes where on the psu board? red yellow white purple
Another question! I have alps 50k pot, how will I conect it for volume?
lol the earth is old tube socket hole from old build ;D
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on May 20, 2009 12:42:37 GMT
DeanO Did you notice my remarks about the JLH ? They were edited in after your reply. Alex
|
|
|
Post by dean0 on May 20, 2009 12:43:56 GMT
Robert I would imagine that it is an on/off switch. The interconnecting strip is alive at all times, so as you said , it needs to be insulated for safety reasons. I am looking forward to the next series of photos too. Alex DeanO You seem to be using an earlier JLH artwork for the JLH from Canjunkie. On the bottom RHS of the photo, there is a missing bit of copper. This can be rectified by not cutting short the inserted resistor's lead, and bending it across to the left to replace the missing copper track. Please post some good quality photos of the JLH before you power it up, as there were a few errors in some of CJ's artwork, around the orientation of the BC550C and BC560C transistor locations. I would suggest that you do not solder in, or cut the leads of the BC550Cs and BC560Cs initially, just bend them underneath to stop them falling out, and then post a few photos so that we can check them for you, to help prevent possible damage. Alex thanks, are you talking about this bit;
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on May 20, 2009 12:44:56 GMT
DeanO Yes. Alex
P.S. Did you check out p.1 of the "Silicon Chip Headphone Amp Tweaks" in this area of the forum ? Re Installing the 2SA1930/2SC5171 in the JLH : Looking at the front of these Toshiba devices, the leads from L to R, are B,C,E. Orient the devices so that the "E " lead (Emitter) goes into the hole with a tiny "E" alongside it on the copper side of the PCB.
|
|
Will
Been here a while!
Ribena abuser!
Member since 2008
Posts: 2,164
|
Post by Will on May 20, 2009 13:29:30 GMT
Dean0,
Sorry mate, wasn't aware there was an error in CJ's artwork! Lucky Alex caught it.
It also appears that it is missing on my JLH, as well.
|
|
|
Post by dean0 on May 20, 2009 16:14:23 GMT
Dean0, Sorry mate, wasn't aware there was an error in CJ's artwork! Lucky Alex caught it. It also appears that it is missing on my JLH, as well. np m8ty, just need conformation this is correct before I solder ps still waiting for parts for the board
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on May 20, 2009 22:51:36 GMT
Dean0, Sorry mate, wasn't aware there was an error in CJ's artwork! Lucky Alex caught it. It also appears that it is missing on my JLH, as well. np m8ty, just need conformation this is correct before I solder ps still waiting for parts for the board deanO The only problem that I can spot so far, is the smaller electro (10uF) on the +VE side is reversed. Alex
|
|
Will
Been here a while!
Ribena abuser!
Member since 2008
Posts: 2,164
|
Post by Will on May 21, 2009 7:44:17 GMT
|
|
|
Post by dean0 on May 21, 2009 11:39:47 GMT
thanks, so basically I have to change the orintation of 10uf cap + side?
|
|
Will
Been here a while!
Ribena abuser!
Member since 2008
Posts: 2,164
|
Post by Will on May 21, 2009 11:41:37 GMT
Yes, that's all you need todo.
|
|
|
Post by dean0 on May 29, 2009 15:59:07 GMT
finished the build and testing now edit have a probelm there is no sound, when i switch the amp on and off the sound kick in for a second then stops, any ideas? -I added a 470pf 100v cap on the psu input +/- as stated, is this correct? -Im using 50k pot; Input pins to rca's Wiper pins to amp rca inputs Ground pins to Ground
|
|
|
Post by dean0 on May 29, 2009 17:57:23 GMT
anyone?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on May 29, 2009 20:46:52 GMT
finished the build and testing now edit have a probelm there is no sound, when i switch the amp on and off the sound kick in for a second then stops, any ideas? -I added a 470pf 100v cap on the psu input +/- as stated, is this correct? -Im using 50k pot; Input pins to rca's Wiper pins to amp rca inputs Ground pins to Ground deano Sorry for delay, but it is only 6.47AM here at the moment. The 470pf capacitor goes across the 2 outer terminals where the secondary of the transformer is connected. If you have a DMM or multimeter you need to check some voltages. First disconnect the JLH from the PSU board, and see if you get approximately +15V and -15V from the centre pin of the the 3 pin output terminal block of the PSU to it's outer terminals. If correct, then connect the PSU DIRECTLY to the HA PCB and see if you get +-15V at the HA PCB power supply terminals. Please advise what results you get. I will be offline for several hours due to shopping etc. The time differences can be a real pain sometimes ! In the meantime, someone else may be able to further assist. Alex
|
|
|
Post by dean0 on May 29, 2009 22:09:23 GMT
thanks bud will do 1st thing tomorow
|
|
|
Post by dean0 on May 30, 2009 14:01:09 GMT
tested voltages on power in amp board, and they measure + = 14.9v - = 14.8v
pretty close to 15v
also when i turn the amp to full, i get very distorted music quetley, but again when i turn amp on i get good sound for 1 second then nothing?
edit what value resistors should i be using in place of the wire wound inductors, I am using 47ohm atm, is this correct? my headphones are 80ohm.
also input caps are 4,70uf 250v poly's
everything else looks correct, all caps are correct, diodes etc.
any ideas?
|
|
robertkd
Been here a while!
Electronics Engineer from sunny Queensland
Posts: 111
|
Post by robertkd on May 30, 2009 14:56:57 GMT
tested voltages on power in amp board, and they measure + = 14.9v - = 14.8v pretty close to 15v also when i turn the amp to full, i get very distorted music quetley, but again when i turn amp on i get good sound for 1 second then nothing? edit what value resistors should i be using in place of the wire wound inductors, I am using 47ohm atm, is this correct? my headphones are 80ohm. also input caps are 4,70uf 250v poly's everything else looks correct, all caps are correct, diodes etc. any ideas? mmm lots but they have little to do with your SC HA,... Alrighty then can you power the unit down remove the op amp and your headphones and any input power back up, tell me what voltage do you get at the headphone socket?? should be ground (0V) plus or minus 1 to 2 volts, this will test the bias circuit and the output devices, you do have all 4 leds illuminated don't you?? Robert PS it looks like you haven't fitted 2 of the LEDS, fit those and see what happens Oh and the rail voltages are fine, as for series resistance that is a matter of personal preference, the output impedance of my SC HA is close to .1 ohm and that's the way I like it ;D
|
|
robertkd
Been here a while!
Electronics Engineer from sunny Queensland
Posts: 111
|
Post by robertkd on May 30, 2009 15:08:08 GMT
Oh Dean0
while your at it frk R3 and R6 off just use wire links
Robert
|
|