I am quite new to this forum, discovered it two month ago, while looking for information about the "famous" aleph amps I had heard about. First did a test-build of the Aleph-X (which works fine, no oscillations 
), and will get a larger project for me to build. But my pre-amp was making trouble, so I decided to build pre-amp and phono stage first. The aleph Ono should be a good starting point to get used to layout again (did it 12 years ago last time ) The layout of Bakmeel would not fit in my case design, so I started my own layout. PCBs manufactured from PCB-Pool here in Germany., and got them on Tuesday. Assembly was completed today, and after finding a bug in the startup mute circuit, which did a perfect mute after 30s by connecting 42V to ground 
(only a diode was reversed), it seems to work fine. This only as an introduction.
Questions is: how to verify correct operation? Compared to my previous Phono stage, it has less bass and more heights. I can not hear any distortion, or see it on the scope, but the sound is somewhat different from what I am used to know. So I took some measurements to check for proper RIAA equalization, and got for an input of 40mVpp some values:
100 Hz ~17Vpp
200Hz 10Vpp
400Hz 6Vpp
500Hz 5Vpp
1kHz 4Vpp
2kHz 3Vpp
3kHz 2.3Vpp
4kHz 2Vpp
8kHz 1Vpp
16kHz ~0.5Vpp
All taken with my scope, not with an audio voltmeter. But I could not find the definition of the RIAA curve. Can anyone help, or confirm the values? A gain of 40mV to 4V at 1Khz seems ok to me. I am using only the MM input, with 220pF loading (sould is the same with different settings).
), and will get a larger project for me to build. But my pre-amp was making trouble, so I decided to build pre-amp and phono stage first. The aleph Ono should be a good starting point to get used to layout again (did it 12 years ago last time ) The layout of Bakmeel would not fit in my case design, so I started my own layout. PCBs manufactured from PCB-Pool here in Germany., and got them on Tuesday. Assembly was completed today, and after finding a bug in the startup mute circuit, which did a perfect mute after 30s by connecting 42V to ground (only a diode was reversed), it seems to work fine. This only as an introduction.Questions is: how to verify correct operation? Compared to my previous Phono stage, it has less bass and more heights. I can not hear any distortion, or see it on the scope, but the sound is somewhat different from what I am used to know. So I took some measurements to check for proper RIAA equalization, and got for an input of 40mVpp some values:
100 Hz ~17Vpp
200Hz 10Vpp
400Hz 6Vpp
500Hz 5Vpp
1kHz 4Vpp
2kHz 3Vpp
3kHz 2.3Vpp
4kHz 2Vpp
8kHz 1Vpp
16kHz ~0.5Vpp
All taken with my scope, not with an audio voltmeter. But I could not find the definition of the RIAA curve. Can anyone help, or confirm the values? A gain of 40mV to 4V at 1Khz seems ok to me. I am using only the MM input, with 220pF loading (sould is the same with different settings).
Attachments
Peter,
look at this link, here the formula for the RIAA curev
http://www.tanker.se/lidstrom/riaa.htm
Nice looking amp you build!
william
look at this link, here the formula for the RIAA curev
http://www.tanker.se/lidstrom/riaa.htm
Nice looking amp you build!
william
one more pic, one more question
The "case" on the picture above is only for testing, will get something in the style of the original one.
One more question: What mesurement equipment would I need to be able to take meassurements of distortion (harmonic and IMD) and S/N ratio ? I have sometimes access to surplus instruments, or could look at ebay. This question is not only for the Ono, but for the other projects in queue. It is good when the DIY-amp sound good, but to be sure would be better
The "case" on the picture above is only for testing, will get something in the style of the original one.
One more question: What mesurement equipment would I need to be able to take meassurements of distortion (harmonic and IMD) and S/N ratio ? I have sometimes access to surplus instruments, or could look at ebay. This question is not only for the Ono, but for the other projects in queue. It is good when the DIY-amp sound good, but to be sure would be better
Attachments
I did some listening to it again, comparing a LP to a CD of the same recording, and the difference is HUGE 
(real, not in audiophile terms ). The MM cardridge I use (Elac 796SP1) is specified for 47kOhms load, max 300pF, so it should fit perfectly. But the sound is like putting the bass gain control to minimum, and the high control to maximum. Again, it does not sound distored, but very stange. Any ideas how to track this ?
(real, not in audiophile terms ). The MM cardridge I use (Elac 796SP1) is specified for 47kOhms load, max 300pF, so it should fit perfectly. But the sound is like putting the bass gain control to minimum, and the high control to maximum. Again, it does not sound distored, but very stange. Any ideas how to track this ?
Hi,
if your RIAA curve fits this can´t really be the cause. Have you tested your old preamp with 40mV? I would do this and see how both compare.
Did you drive a load when testing your Ono (preamp or load resistor). In case of a mistake made somewhere this could also be of influence.
hope this helps,
william
if your RIAA curve fits this can´t really be the cause. Have you tested your old preamp with 40mV? I would do this and see how both compare.
Did you drive a load when testing your Ono (preamp or load resistor). In case of a mistake made somewhere this could also be of influence.
hope this helps,
william
This morning I did some more testing, using a HP3468A true RMS voltmeter, which has <1% error up to 50kHz. Now with 4mV sinus input signal. I checkit it with open output first, then loaded with 1kOhms, which did not give any influence on the frequency curve (except below 25 Hz). All is +- 0.1dB up to 4300Hz, and then rises to +3.3dB at 21.000 Hz. C4 is 10nF, C5 is 2.7nF parallel to C6 with 33nF, all three are 1% tolerance PP foil types. R8 is 7.32k and R9 is 88.7K. But if I understand right, high frequency EQ is done by C8 (10nF) and R28 (150Ohms) only. Checked all values and connections, but can not find an error there.
And there is too much noise (not hum) at the output, 5mV RMS with shorted input (MM). How much should be ok?
Both channels behave same. And only <0.5mV noise on the +-30V supply lines.
And there is too much noise (not hum) at the output, 5mV RMS with shorted input (MM). How much should be ok?
Both channels behave same. And only <0.5mV noise on the +-30V supply lines.
I forgot to write that I found one error, before taking the more precise measurements, R28 and R82 had wrong values. Now the sound is ok, no missing bass, but the +3dB on high frequency can be real. Sound is a little bit "sharp". But maybe the noise contributes to this?
If the output noise is highter than the power supply noise, it must come from the first stage?
If the output noise is highter than the power supply noise, it must come from the first stage?
pquadrat
R28 and R82 should both be 150R.
I felt the same as you when i built my first Ono and replaced my
CJ-PV11.
But after listening to the Ono for a couple of weeks, i connected back the CJ and i couldn't stand it, esp. in the lower frequencies.
I think it's the complete lack of colorations that makes someone think the Ono is weak in bass.
Relax and give it time to burn in. After 40-50 hours of playing music highs will also lose the extra sharpness and the sound will become balanced.
I'm using 2 Onos (have 2 turntables), both with low output mc's
and i feel very comfortable listening to my records.
It would be a good idea to leave yor Ono "on" all the time.
The noise you are mentioning is a problem because the thing is
practically noiseless.
Good luck
Nick
R28 and R82 should both be 150R.
I felt the same as you when i built my first Ono and replaced my
CJ-PV11.
But after listening to the Ono for a couple of weeks, i connected back the CJ and i couldn't stand it, esp. in the lower frequencies.
I think it's the complete lack of colorations that makes someone think the Ono is weak in bass.
Relax and give it time to burn in. After 40-50 hours of playing music highs will also lose the extra sharpness and the sound will become balanced.
I'm using 2 Onos (have 2 turntables), both with low output mc's
and i feel very comfortable listening to my records.
It would be a good idea to leave yor Ono "on" all the time.
The noise you are mentioning is a problem because the thing is
practically noiseless.
Good luck
Nick
Nick,
thanks for Your detailed and encourageing posting. I will check it all again tomorrow, because the +3dB on the high end can easily be a measurement problem on this small signals, or the noise contributes to this. But if I find out that ther IS a +3dB EQ error, I have to fix it, and will not use it until then. I have to my audio equipment the same expectations than to my messurement equipment, it has to met specifications, has to work trouble-free and of high quality by design. Of course it has to sound good, but I do not want good-sounding, but bad objective data stuff.
Nick, Jens and others,
how about the noise output of Your Onos? I can see a about 10mVpp noise on the scope,
and get a reading of about 5mVRMS on my digital voltmeter. There is no noise on the
supply lines which I could detect (<0.5mV).
How much noise should be allowed by the specifications, the service manual has
"-90 dB ref. 10mV input(MM), which is not clear to me.
all:
Any hints about checking this (and other) circuits for proper operation/meeting
the specifications, other than listening to music? With eqipment that DIYers can
afford?
thanks for Your detailed and encourageing posting. I will check it all again tomorrow, because the +3dB on the high end can easily be a measurement problem on this small signals, or the noise contributes to this. But if I find out that ther IS a +3dB EQ error, I have to fix it, and will not use it until then. I have to my audio equipment the same expectations than to my messurement equipment, it has to met specifications, has to work trouble-free and of high quality by design. Of course it has to sound good, but I do not want good-sounding, but bad objective data stuff.
Nick, Jens and others,
how about the noise output of Your Onos? I can see a about 10mVpp noise on the scope,
and get a reading of about 5mVRMS on my digital voltmeter. There is no noise on the
supply lines which I could detect (<0.5mV).
How much noise should be allowed by the specifications, the service manual has
"-90 dB ref. 10mV input(MM), which is not clear to me.
all:
Any hints about checking this (and other) circuits for proper operation/meeting
the specifications, other than listening to music? With eqipment that DIYers can
afford?
PCB
antness,
I did the PCB design myself, similar to the original Aleph Ono layout. There is another thread about an Ono PCB http://www.diyaudio.com/forums/showthread.php?s=&threadid=6047&highlight=xono
but there is not much news. I do not want to make this public until it is clear if Bakmeel can finish his design.
And I have to fix the noise problem first. Otherwise the layout is working, only minor changes are needed for
better fitting of the 10uF caps, and larger mounting holes. If there is interest, I could order a small production
of these boards.
about the noise: from the 90dB S/N spec in the Ono manual, I would expect to see about 50 to 100uV
noise on output, it that true?
antness,
I did the PCB design myself, similar to the original Aleph Ono layout. There is another thread about an Ono PCB http://www.diyaudio.com/forums/showthread.php?s=&threadid=6047&highlight=xono
but there is not much news. I do not want to make this public until it is clear if Bakmeel can finish his design.
And I have to fix the noise problem first. Otherwise the layout is working, only minor changes are needed for
better fitting of the 10uF caps, and larger mounting holes. If there is interest, I could order a small production
of these boards.
about the noise: from the 90dB S/N spec in the Ono manual, I would expect to see about 50 to 100uV
noise on output, it that true?
Seems that all that (ph)Ono stuff gets not much interest on this forum? Nothing new from Bakmeel's project, no replies to this thread regarding noise problem.
So I wil give some news about this one. I could now measure the noise more exactly, it is about 10 times as much as I would expect, 300uV on output, with shorted input. From the manual I would expect 30uV. Is there anything about special low-noise components? I put some caps around the power supply, across the rectifier diodes, no change at all.
So I wil give some news about this one. I could now measure the noise more exactly, it is about 10 times as much as I would expect, 300uV on output, with shorted input. From the manual I would expect 30uV. Is there anything about special low-noise components? I put some caps around the power supply, across the rectifier diodes, no change at all.
Okay, here we go!
The Ono is silent, nearly noiseless, more as any other phono amp I have heard over so many years!
I don’t use special low-noise components in my Ono clone, but from my experience with different PSUs I realise, the overall performance of this phono amp is hardly related to the PSU, more as I thought. Anyhow, I never had noise problems as you explains, irrelevant of the different PSUs I tested and if I understand you correct, your PSU is silent, too.
Peter, do you use in the original semiconductors or any replacements? Do you measure similar figures as marked in Wayne’s schematic? Do you use the RCA or XLR out, is your inverter circuit populated?
If you like me to check your schematics (PSU+AMP) please send copies.
Jens
BTW: I’m in touch with Bouke regarding his Ono clone.
The Ono is silent, nearly noiseless, more as any other phono amp I have heard over so many years!
I don’t use special low-noise components in my Ono clone, but from my experience with different PSUs I realise, the overall performance of this phono amp is hardly related to the PSU, more as I thought. Anyhow, I never had noise problems as you explains, irrelevant of the different PSUs I tested and if I understand you correct, your PSU is silent, too.
Peter, do you use in the original semiconductors or any replacements? Do you measure similar figures as marked in Wayne’s schematic? Do you use the RCA or XLR out, is your inverter circuit populated?
If you like me to check your schematics (PSU+AMP) please send copies.
Jens
BTW: I’m in touch with Bouke regarding his Ono clone.
Jens,
thanks for answering. The schematics are 1:1 of the Ono Service manual, and all parts are original ones, IRF output transistors, japanese input transistors, and the inverter for balanced output is populated. All resistors metal-film 1%. But I am using it unbalanced up to now, Aleph P not finished yet.
I get all voltages as stated in the schematics, 1V across R67 and 0.35V across R28 (33R) after adjustment.
I would expect the problem in the first stage , the 2SK389 differential pair, but I have no idea how to track it. Noise levels are to low to measure there. And just swapping parts?
thanks for answering. The schematics are 1:1 of the Ono Service manual, and all parts are original ones, IRF output transistors, japanese input transistors, and the inverter for balanced output is populated. All resistors metal-film 1%. But I am using it unbalanced up to now, Aleph P not finished yet.
I get all voltages as stated in the schematics, 1V across R67 and 0.35V across R28 (33R) after adjustment.
I would expect the problem in the first stage , the 2SK389 differential pair, but I have no idea how to track it. Noise levels are to low to measure there. And just swapping parts?
Peter,
As you explains, your Ono has similar noise problems in both channels, therefore I don’t believe you’ll solve the problem by swapping parts. Anyhow, I would start to replace the 2SK389 with one from a different source but before this, why not trying to use batteries (3+3 9V) instead of the PSU and see what goes on...
Jens
As you explains, your Ono has similar noise problems in both channels, therefore I don’t believe you’ll solve the problem by swapping parts. Anyhow, I would start to replace the 2SK389 with one from a different source but before this, why not trying to use batteries (3+3 9V) instead of the PSU and see what goes on...
Jens
Jens,
thanks for the 9V-battery-tip. I got 6 pcs for +-27V, but only found out that most of the noise is NOT from the power supply. There was a little difference, which I could cure by different ground line from PS to preamp. I even tried to put the ps two meters from the preamp, makes no difference at all. The regulation seems to be fine, can not hear a difference between battery or line now.
Next I will replace the 2SK389s, and try to find the source of the noise in the circuit by removing connections between stages.
-peter
thanks for the 9V-battery-tip. I got 6 pcs for +-27V, but only found out that most of the noise is NOT from the power supply. There was a little difference, which I could cure by different ground line from PS to preamp. I even tried to put the ps two meters from the preamp, makes no difference at all. The regulation seems to be fine, can not hear a difference between battery or line now.
Next I will replace the 2SK389s, and try to find the source of the noise in the circuit by removing connections between stages.
-peter
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