Hps 5.1

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#162
#163
HPS5.1

Hi Greg,

You need to get a login for HiFi Engine | Download Free User/ Service Manuals, Amplifier, Receiver, CD, Tape, Tuner, Video, my original link was wrong... sorry.
If the LM317/LM337 o/p's are set for 21.25 volts you need as a minimum i/p of around 3 volts above that. Have to watch/see the minimum voltage of the i/p sawtooth to see if it makes the i-o differential spec, this depends on the current drawn and the size of the big filter ecap. I usually use, as a min the same ACV as the o/p DCV. So in this case, I'd use 21VAC (21 * 1.414 = for a 29.7 Vpk), with a min of 1000uF bulk ecap.
Check out this thread for more info
http://www.diyaudio.com/forums/power-supplies/216409-power-supply-resevoir-size-new-post.html

I did some further investigation of HPS5.1, LME49870 is spec'd at max 44V, so a +/-22V supply is fine.(VCCL/VEEL)
The cmult filter is probably properly set for around +/-18V for the OPA211 & LMH6321(VCCL1/VEEL1)

Rick
 
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#164
hook-up

Thanks Rick,

I finally have most of the parts soldered apart from a 634ohm resistor, as it turns out I have 634Kohm. Not far now.
I have the PS sorted however I am in a jam with the hookup. I take it that the connections (P201) next to the loading etc are the input and the connectors (P202) near the 6.8Uf caps are the output? The problem that I am having is working out the relay connections as there are 2 per channel. How do the jumper/connections (P204 & P205) work for MM and MC? It is doing my head in. If you can help, it would be greatly apreciated as I am so close however so far.

Cheers
Greg
 
#165
Hi Greg,
(P201) next to the loading etc is the input from the phono cartridge.
(P202) near the 6.8uF caps is the output
(P204) is the connection to operation the gain relay, assuming a 24V relay since it comes from the VCC1 supply, which was calculated to be around 22V. If you look close enough at the picture, it shows the relay as a NEC "EB2-24NU"
(P205) I assume is meant to operate a front panel LED to show visual indication of the gain setting position.
How do the jumper/connections (P204 & P205) work for MM and MC?
Use a switch between P204, closing the switch will close the relay, lowering the gain as it lower the feedback Rf. An LED across P205, anode to pin 1.
Rick
 
#166
Oh no

Thanks for all of your help Rick, it's really appreciated.

Well here is an update:

I got everything running straight off the bat and it sounded wonderful however I then decided to place it in an enclosure and on hooking up the power I reversed the polarity pvccl & pvddl on one channel. The result is that the voltage on the outputs of the lm337 and lm317 now fluctuates on the output. I had thought that the diodes d401, d402, d405 & d406 would protect the regulators in case this happens.

The sound out of the right channel starts for a second and then drops out for 2-3 seconds with a small thump and then repeats etc.

What have I potentially damaged both in the regulation and further down stream? I'm hoping that it is only the lm337 & lm317nand perhaps the diodes mentioned above. I don't just want to start replacing things as I have to order new parts from the USA. Takes a while living in Australia


Any help would really make my day

Cheers
Greg
 
#167
Greg,
You should be able to find these reg parts in Australia I would think, they are very common, made by multiple suppliers.
Can not be sure that it is the regs or other parts down the line causing this fluctuation.Have to run a few tests on the PS separately to see the no-load to full load reg performance to isolate issue.
Rick
 
#172
Well I found the problem, one dry solder joint on a cap and a bad phono cable. It's back up and running. Just goes to show that the diodes actually do protect the ps! Man I'm really impressed, I'm spinning some old Bauhaus for a change and don't feel like moving off the couch. I still have to decide on the 6.8uf output caps, as I have some generic polypropylenes in place. What would the least uf that it could get away with?
Greg, what caps did you end up using? (Space is an issue)

Guys thanks for all of the help.

Cheers
Greg
 
#174
PixelPlay said:
Well I found the problem, one dry solder joint on a cap and a bad phono cable. It's back up and running. Just goes to show that the diodes actually do protect the ps! Man I'm really impressed, I'm spinning some old Bauhaus for a change and don't feel like moving off the couch. I still have to decide on the 6.8uf output caps, as I have some generic polypropylenes in place. What would the least uf that it could get away with?
Greg, what caps did you end up using? (Space is an issue)

Guys thanks for all of the help.

Cheers
Greg
Click to expand...

Glad it is sorted mate. I used Auricaps Auricap Audio Capacitors, I am sure there are better options but your room will probably play a bigger influence 🙂
 
#175
I will sort something out for you 🙂
Click to expand...
Thx Greg, glad to hear that you solved the problem & are enjoying this fine design. What phono cartridge/TT are you using?
O/P couling cap depends on the input R(Z) of the following stage (usually around 50K) and how much low pass filtering is required. Are you using the rumble filter? I would say 3.3uF would probably be a minimum with a 50K load. -3db= 1/(2piRC) ~1Hz
Rick
 
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#178
I am coming to the end of the HPS 5.1 build and now testing the phono amp. I have a couple of questions –

Regarding the input JFET’s, the designer quotes “The JFETs Vds is kept to around 3V, so that they don't heat up (affecting the noise) and also no hot carriers injection occurs”.

I have a Vds of 3.34V as a result of the reference from the 2 GLED’s being 3.96V. I am using an Agilent Green LED (part no HSMG-C265). I could replace these for an orange type from the same manufacture, this would give around 3.7V ref or I could reduce the current through the LEDs.

The questions I have are-

1.Should I be concerned that the VREF is slightly higher? I calculate the power dissipation to be 36mW at present for each JFET, reducing the reference would give approximately 30mW

2. Does reducing the current through the LED’s increase their resistance and hence noise? (I don’t feel this is a sensible route as the value of the I limiting resistor will need to be increase significantly).

Regards,
 
#180
Lesson learned : Lower the rail voltages on your HPS 5.1 Amps.
I built my HPS a few years ago and since then have only powered it up a few times in the weekends. A few weeks ago a channel went dead on the HPF. Since i did not have the time to find out what the problem was at the time, i bypassed the filter. Today, the amp would not work at all. I opened it up and measured the outputs before the caps where i read -21.98V DC.
The op-amp rails both measured just above 22V. I remember that when building this beast, i set the rail voltages lower than Ovidiu's schematics, somewhere just above 21V. It looks like time and the high temperature have taken their toll and blew all of the 22V rail op-amps. That is 6 of them
I advise you check your rail voltages and lower them if necessary.
 
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