Nico is being gracious, giving me the chance to explain......
However, I have a paper on this, attached.
This might cause a few raised eyebrows and might suggest I leave the forum, but here it is.......
Apologies, Nikos, as it happens, Nikos is the name of my favourite Cafe in Melbourne!!
Hugh
However, I have a paper on this, attached.
This might cause a few raised eyebrows and might suggest I leave the forum, but here it is.......
Apologies, Nikos, as it happens, Nikos is the name of my favourite Cafe in Melbourne!!
Hugh
Good Day fellow members,
I believe that I am ready to supply power to my AN project. I will be powering up into an 80hm 100W resistor on a heatsink, one channel at a time. I will attach a picture and follow it by an explanation of what the picture is showing. I am looking for comments and especially comments about what I can measure as I do not have a scope, only a couple of DMM's. So here goes:
pic1 - an overall shot of layout
Starting at the bottom, it shows the fan controller/cables. On Rside it shows the 8ohm/100W resistor and HS. Then comes the amps, cpu HS's, slb's on each side (these will occupy the area between the cpu HS's at a later date). Then the transformers and a peek at the SFP on the front wood panel.
pic2 - SFP-trans wiring-star ground
This pic shows the transformer wiring (hopefully used wago's correctly), the SFP, and the star grounding.
pic3-cpu HS and the amps
Shows the star ground again. HS attached to star ground. Shows the flying leads from the MFet's under the alu clamp. Those small makerbeam clamps are for attaching the slb's and their heatsink plates. Shows the fan cables that will have to come through the back panel or through the chassis base at a later date.
pic4- Rchannel ready to test (I think)
This shows the sec's going to the slb, the double twisted red wire from slb chassis rtn to the star ground, slb ground to amp ground. I have connected 2 wires from amps speaker out's to the 8ohm/100w resistor using a faston tab inserted into a female connector. I have hooked up the resistor using an alligator clip to the faston and also the DMM leads to this faston to hopefully measure DC offset. I did not bother with a trim pot and just used a 22R resistor on the amp board.
Question: have I got it set up OK for testing?
pic5- Lchannel
Basically the same as the right channel, just waiting for testing. The 2 long wires w/ the blue tape on the ends are the wires for the low cap psu. I have not yet attached the transformer wire shields to the star ground.
Question: Can the shield wires be twisted together into one connector or do they have to be separate grounds when attached to the star ground.
Thanks for the looks and please let me know if I have missed anything important.
Regards,
MM
I believe that I am ready to supply power to my AN project. I will be powering up into an 80hm 100W resistor on a heatsink, one channel at a time. I will attach a picture and follow it by an explanation of what the picture is showing. I am looking for comments and especially comments about what I can measure as I do not have a scope, only a couple of DMM's. So here goes:
pic1 - an overall shot of layout
Starting at the bottom, it shows the fan controller/cables. On Rside it shows the 8ohm/100W resistor and HS. Then comes the amps, cpu HS's, slb's on each side (these will occupy the area between the cpu HS's at a later date). Then the transformers and a peek at the SFP on the front wood panel.
pic2 - SFP-trans wiring-star ground
This pic shows the transformer wiring (hopefully used wago's correctly), the SFP, and the star grounding.
pic3-cpu HS and the amps
Shows the star ground again. HS attached to star ground. Shows the flying leads from the MFet's under the alu clamp. Those small makerbeam clamps are for attaching the slb's and their heatsink plates. Shows the fan cables that will have to come through the back panel or through the chassis base at a later date.
pic4- Rchannel ready to test (I think)
This shows the sec's going to the slb, the double twisted red wire from slb chassis rtn to the star ground, slb ground to amp ground. I have connected 2 wires from amps speaker out's to the 8ohm/100w resistor using a faston tab inserted into a female connector. I have hooked up the resistor using an alligator clip to the faston and also the DMM leads to this faston to hopefully measure DC offset. I did not bother with a trim pot and just used a 22R resistor on the amp board.
Question: have I got it set up OK for testing?
pic5- Lchannel
Basically the same as the right channel, just waiting for testing. The 2 long wires w/ the blue tape on the ends are the wires for the low cap psu. I have not yet attached the transformer wire shields to the star ground.
Question: Can the shield wires be twisted together into one connector or do they have to be separate grounds when attached to the star ground.
Thanks for the looks and please let me know if I have missed anything important.
Regards,
MM
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@MM
Congratulations for your effort.I hope it will be crowned with success. I hope you have tested your power supplies with or without load before start up ...Now, in terms of construction, as I have said before, I would prefer the heatsinks with the fans in an upright position ..... but this is your choice based on everyone's reasoning.. Now for me the oscilloscope is absolutely necessary since maybe maybe I say observed spikes relative to the lower part of the square signal and may need a correction in relation to the grounding or even more specialized corrections.Α member from Sweden had shown something like this, but I don't know if it finally solved it... Maybe i found the post later.....
Congratulations for your effort.I hope it will be crowned with success. I hope you have tested your power supplies with or without load before start up ...Now, in terms of construction, as I have said before, I would prefer the heatsinks with the fans in an upright position ..... but this is your choice based on everyone's reasoning.. Now for me the oscilloscope is absolutely necessary since maybe maybe I say observed spikes relative to the lower part of the square signal and may need a correction in relation to the grounding or even more specialized corrections.Α member from Sweden had shown something like this, but I don't know if it finally solved it... Maybe i found the post later.....
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Myles,
It looks good so throw the switch.
With no signal input measure the voltage across the two source resistors.
It should be 740-780 millivolts.
Then measure the offset at the speaker output wrt ground.
It should within 15 millivolts, plus or minus.
If both measures are OK, connect input source and speaker and start the listening tests!
Congratulations, a difficult project well concluded...
Hugh
It looks good so throw the switch.
With no signal input measure the voltage across the two source resistors.
It should be 740-780 millivolts.
Then measure the offset at the speaker output wrt ground.
It should within 15 millivolts, plus or minus.
If both measures are OK, connect input source and speaker and start the listening tests!
Congratulations, a difficult project well concluded...
Hugh
Thanks Hugh and Nikos,
Couple of quick questions:
1. The source resistors are the 2 white BPR type resistors, correct?
2. Does one need to adjust the SLB dropout voltage? I only adjusted with no load attached.
3. Is a voltage check across R111 needed to adjust the bias?
4. Trans shield wires: can they be combined in 1 connector to ground or need to be separate?
Thanks again,
MM
Couple of quick questions:
1. The source resistors are the 2 white BPR type resistors, correct?
2. Does one need to adjust the SLB dropout voltage? I only adjusted with no load attached.
3. Is a voltage check across R111 needed to adjust the bias?
4. Trans shield wires: can they be combined in 1 connector to ground or need to be separate?
Thanks again,
MM
1. Yes
2 .No .maybe a litle correction after....
3. No. 3.3k its for measure on it 8.2-8.6V the bias on LTP about 2.3_2.6 mA a pot about 500Ω after 6.8k for 8R or 5k for 4R ajust the bias on LTP
4. I dont know once i dont have on trafos shield wire ....maybe other members can give an answer about those cables....
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Hi Mr Hugh.
Based on your white paper and what I read the Alpha Nirvana amplifier could be characterized with monotonic decrease harmonics profile?
Thank you for all...
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Hi Myles,
Shielding on the secondaries is a good idea, but not actually essential on this amp.
When you turn the amp on and measure offset, as long as it is below + or - 15mV all is well. You can trim it by changing one of the long tail pair supply resistors (R114, the trimpot on my schematic). When you have the offset very low, remove the trimmer, measure it, and than insert a NPV resistor in its place. R112 is series with the trimpot/R114, so don't change that one and no need to measure it either.
If the SLBs both work and pass current you can measure between EMITTER and COLLECTOR on the large pass transistor. It needs quite a bit of cooling because it passes the 1.7A quiescent current and higher current at heavy signal. That voltage should be 2.8V - 3V, no more. You have a trimmer on the SLB pb to adjust this. This can be done well after you have the amp running music, BTW.
Full steam ahead! 🚄
Nikos,
Yes, monotonic decrease of the harmonics, as described in the paper. All my amps follow this approach.
Hugh
Shielding on the secondaries is a good idea, but not actually essential on this amp.
When you turn the amp on and measure offset, as long as it is below + or - 15mV all is well. You can trim it by changing one of the long tail pair supply resistors (R114, the trimpot on my schematic). When you have the offset very low, remove the trimmer, measure it, and than insert a NPV resistor in its place. R112 is series with the trimpot/R114, so don't change that one and no need to measure it either.
If the SLBs both work and pass current you can measure between EMITTER and COLLECTOR on the large pass transistor. It needs quite a bit of cooling because it passes the 1.7A quiescent current and higher current at heavy signal. That voltage should be 2.8V - 3V, no more. You have a trimmer on the SLB pb to adjust this. This can be done well after you have the amp running music, BTW.
Full steam ahead! 🚄
Nikos,
Yes, monotonic decrease of the harmonics, as described in the paper. All my amps follow this approach.
Hugh
So, not the power up I was hoping for. I started with the left channel and I could not get the voltage passed about 70V as my DBT was glowing brightly. No smoke or fire. I shut it down and tested the right channel with the same results. I started checking the amp boards and found that I had connected the N MFets incorrectly on my amp boards. I desoldered them and connected the proper way.
I powered up the left channel and at about 50V applied, the DBT is glowing and pulsating. The led's on the psu and the amp board were pulsating also. I shut that down and tested the right channel.
The right channel I can raise the voltage to 70V before DBT is glowing. The led on the -side of psu is lit and the V-led on the amp board is lit. The led on + side of psu is not lit and the V+led on the amp board is not lit.
So I thought I would start trouble shooting by getting the SLB psu's operating correctly. This is what I have so far:
Left psu: 115V applied and 31.4 V measured unloaded on both sides. both led's illuminated. Measured V between emitter and collector of the BJT's at 2.36V. Transistor's feel slightly warm. Looks good
Right psu: 115V applied and - 31.3V measured unloaded with led illuminated. Measured V between emitter and collector at 2.36V. Transistor feel slightly warm. Looks good
115V applied and + 0.00V measured unloaded and no led illuminated. Measured V between emitter and collector at 0.00V. Transistor feels cold.
I am not sure what happened when powering up the amp with the N channel MFet's wired incorrectly, but it did something. My first step will be to check the led on the + side of the right psu and get it working properly.
Question: If the led is not illuminating, does this affect the operation of the BJT transistor (ie: why I measured 0.0V from emitter to collector), or is the BJT probably toast ?.
Thanks for the help, once I solve the psu problem, I will trouble shoot the amp boards. Good learning experience.
MM
I powered up the left channel and at about 50V applied, the DBT is glowing and pulsating. The led's on the psu and the amp board were pulsating also. I shut that down and tested the right channel.
The right channel I can raise the voltage to 70V before DBT is glowing. The led on the -side of psu is lit and the V-led on the amp board is lit. The led on + side of psu is not lit and the V+led on the amp board is not lit.
So I thought I would start trouble shooting by getting the SLB psu's operating correctly. This is what I have so far:
Left psu: 115V applied and 31.4 V measured unloaded on both sides. both led's illuminated. Measured V between emitter and collector of the BJT's at 2.36V. Transistor's feel slightly warm. Looks good
Right psu: 115V applied and - 31.3V measured unloaded with led illuminated. Measured V between emitter and collector at 2.36V. Transistor feel slightly warm. Looks good
115V applied and + 0.00V measured unloaded and no led illuminated. Measured V between emitter and collector at 0.00V. Transistor feels cold.
I am not sure what happened when powering up the amp with the N channel MFet's wired incorrectly, but it did something. My first step will be to check the led on the + side of the right psu and get it working properly.
Question: If the led is not illuminating, does this affect the operation of the BJT transistor (ie: why I measured 0.0V from emitter to collector), or is the BJT probably toast ?.
Thanks for the help, once I solve the psu problem, I will trouble shoot the amp boards. Good learning experience.
MM
Hi did you test the N Channel fet before solder again?
also check the BJT transistor ? you refer for the BD140?
Can you post a macro photo for both sides of AN39 board?
Are you sure for proper installation about leds?
also check the BJT transistor ? you refer for the BD140?
Can you post a macro photo for both sides of AN39 board?
Are you sure for proper installation about leds?
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Thanks Nikos,
1. I have not yet tested the N Mfet. Once I fix the psu, I will worry about testing the NMfet.
2. The BJT I am referring to is the 2SA1943 on the +V side of the psu. I am asking if D1 the led affects the function of the BJT. There is no voltage between emitter and collector.
3. I will post shots of the AN39 boards, once I begin to trouble shoot them. This will happen after I have my psu working correctly.
4. led's were all working correctly when I first tested the psu without load. Now one is not working on the psu and also on the V+ side of the amp board.
As I said in post 3332, I am diagnosing the psu first, then the amp boards and Mfets.
1. I have not yet tested the N Mfet. Once I fix the psu, I will worry about testing the NMfet.
2. The BJT I am referring to is the 2SA1943 on the +V side of the psu. I am asking if D1 the led affects the function of the BJT. There is no voltage between emitter and collector.
3. I will post shots of the AN39 boards, once I begin to trouble shoot them. This will happen after I have my psu working correctly.
4. led's were all working correctly when I first tested the psu without load. Now one is not working on the psu and also on the V+ side of the amp board.
As I said in post 3332, I am diagnosing the psu first, then the amp boards and Mfets.
Ok its clear now.....
dont think it if you have another 2sa1943 and bd139 change them ...also change the diode 1n4004 look for burn resistors 75Ω - 68Ω - 10Ω .
dont think it if you have another 2sa1943 and bd139 change them ...also change the diode 1n4004 look for burn resistors 75Ω - 68Ω - 10Ω .
Myles,
What is the Vbe on the 2SA1943?
And what is the. DBT?
Can you put up a schem of your regulator with all pionts showing voltage wrtground?
Sometimes drawing up the schematic with measured voltage can show the problem right away. Just using words is not enough....
Hugh
What is the Vbe on the 2SA1943?
And what is the. DBT?
Can you put up a schem of your regulator with all pionts showing voltage wrtground?
Sometimes drawing up the schematic with measured voltage can show the problem right away. Just using words is not enough....
Hugh
Thanks Nikos and Hugh,
Now I am going to get into the meat of diagnostics and trouble shooting. It makes me nervous as I have not done much testing on a "live circuit". I will print out a schematic of the slb, so I can mark it up.
Question: I will use one of the many grounds on the slb and connect the black DMM probe, correct? and diagnose the circuit with the red probe.
Hugh, DBT is the dim bulb tester, I am using with a 100w light bulb. Setup is: mains>variac>DBT>apparatus being powered.
Edit to above: I noticed that one of my secondary wires had come loose from the faston tab. After re-attaching the led on V+ side is now illuminating. Good news
I applied 115V to the circuit and the Vbe on the 2sa1943 is 0.0V. I checked the Vbe on the 2sc5200 also and it is 0.0V also.
I measured the Vec on the 2sa1943 and found it was 0.0V. I changed to mV scale and the measurement is fluctuating between 0.0mV and 24mV. This seems like strange behaviour. I measured the Vec on the 2sc5200 and it is 2.36V.
I will wait until this information is absorbed and if any recommendations put forward, before I start testing the circuit and marking the schematic. Slow and methodical steps😉
MM
Now I am going to get into the meat of diagnostics and trouble shooting. It makes me nervous as I have not done much testing on a "live circuit". I will print out a schematic of the slb, so I can mark it up.
Question: I will use one of the many grounds on the slb and connect the black DMM probe, correct? and diagnose the circuit with the red probe.
Hugh, DBT is the dim bulb tester, I am using with a 100w light bulb. Setup is: mains>variac>DBT>apparatus being powered.
Edit to above: I noticed that one of my secondary wires had come loose from the faston tab. After re-attaching the led on V+ side is now illuminating. Good news
I applied 115V to the circuit and the Vbe on the 2sa1943 is 0.0V. I checked the Vbe on the 2sc5200 also and it is 0.0V also.
I measured the Vec on the 2sa1943 and found it was 0.0V. I changed to mV scale and the measurement is fluctuating between 0.0mV and 24mV. This seems like strange behaviour. I measured the Vec on the 2sc5200 and it is 2.36V.
I will wait until this information is absorbed and if any recommendations put forward, before I start testing the circuit and marking the schematic. Slow and methodical steps😉
MM
Myles,
Neither of your regulators are working but I suspect there is no power is reaching them
What is the voltage at the EMITTERS of A1943 an C5200 wrt ground (any ground is fine). It should around 30V pos and neg respectively.
If there is no voltage at the reg inputs check your trafos are running and your bridge rectifiers are correct by measuring voltage at the first cap after the bridge.
Hugh
Neither of your regulators are working but I suspect there is no power is reaching them
What is the voltage at the EMITTERS of A1943 an C5200 wrt ground (any ground is fine). It should around 30V pos and neg respectively.
If there is no voltage at the reg inputs check your trafos are running and your bridge rectifiers are correct by measuring voltage at the first cap after the bridge.
Hugh
Hugh,
While I was waiting for your post, I decided to check for various V readings in the circuit. I started measuring at R7 and R8 and carried on to the SLB outputs. I did this for both SLB's and I will post these hopefully tomorrow after work.
I was feeling so good that I was able to do some live testing, I tried to test R4 (the BPR's in the CRC). Well there was one hell of a spark, the DBT illuminated brightly, a burnt smell, and the NV side of the SLB went dark. Now I am unable to power it up. Will have to remove it from the heatsink and see what the damage is.
Hugh, I just tested the V at the emitters of the A1943 and C5200 at 33.6V each on the good SLB.
To test the lt4320 reg do I probe the In1 pin wrt gnd ?. If correct I will do this tomorrow and post the schematic with the various voltages I measured.
Thanks for the help, really learning even if I make mistakes like probing R4.
Need some sleep, been a long day
MM
While I was waiting for your post, I decided to check for various V readings in the circuit. I started measuring at R7 and R8 and carried on to the SLB outputs. I did this for both SLB's and I will post these hopefully tomorrow after work.
I was feeling so good that I was able to do some live testing, I tried to test R4 (the BPR's in the CRC). Well there was one hell of a spark, the DBT illuminated brightly, a burnt smell, and the NV side of the SLB went dark. Now I am unable to power it up. Will have to remove it from the heatsink and see what the damage is.
Hugh, I just tested the V at the emitters of the A1943 and C5200 at 33.6V each on the good SLB.
To test the lt4320 reg do I probe the In1 pin wrt gnd ?. If correct I will do this tomorrow and post the schematic with the various voltages I measured.
Thanks for the help, really learning even if I make mistakes like probing R4.
Need some sleep, been a long day
MM
Myles,
You have 33V at both SLB emitters but may have blown the neg 4320.
Check the pinout on the npn master on the pos SLB and the PNP master on the neg SLB.
I am concerned this transistor is not operating; are you using the correct transistor.
You appear to have discharged the neg SLB cap; took care you are measuring voltage and not current.
Please post the schematic you are working from, otherwise we may not be on the same page....
Hugh
You have 33V at both SLB emitters but may have blown the neg 4320.
Check the pinout on the npn master on the pos SLB and the PNP master on the neg SLB.
I am concerned this transistor is not operating; are you using the correct transistor.
You appear to have discharged the neg SLB cap; took care you are measuring voltage and not current.
Please post the schematic you are working from, otherwise we may not be on the same page....
Hugh