cocolino said:
Hi grataku,
Hey..... that`s just great ...actually much better than my suggestion!
How comes that I have not thought about this!?
Hugo, what do You think about this slight modification?
I believe WAF will be delighted!!!
Euhh...I'm not sure I understand this...bit simple minded sometimes.
Are you guys talking about rebuilding the house at twice the size???
Maybe its because I never watched the american football commentators
Ok, ok, next time I have a few hours of spare time, I'll try the proposed setup. A towel will not be enough, I'll have to lift those guys 0.5m high because the wooden floor is higher than the normal level of the house, remove them spikes and so on...
/Hugo - just noticed a big, big window behind the listening seat...
jh6you said:
Thanks JH,
When talking about the monolithic amp I refer to
http://www.diyaudio.com/forums/showthread.php?postid=153484#post153484
The dynamics are much better than with any amp I heard. I had a spare moment to listen to Tori Amos again this afternoon, and for the first time I could clearly hear that there was a lot of noise in the recording. Maybe it is the Leslie again in the beginning of the first track of StrangeLittleGirls.
Nora Jones absolutely shines. On 'Come Away With Me' here beautiful voice with sober instrumentation really took me away.
She was just here standing next to me whispering…and this is only MP3 and a AlephX monoblock. I promise everyone here and now to buy the album.
Whooo, I'm getting poetic here.
The mad drums and bass on Ben Harper's ‘Glory & Consequence’
for the first time reveal the real potentials of the 802's.
In 'I shall Not Walk Alone' from the same album, we sit alone with Ben around the fire together with the straight in your face, very detailed guitar and background violin. Stunning...
On 'With God On Our Side' from The Neville Brothers I can hear Aaron Neville's tong turn in his month.
Too bad my ears were better 20 years ago.
/Hugo – went too much to too loud concerts in the past…
Netlist said:
Hi Hugo
Norah Jones, come away with me.
For me, she sings the songs with her voice resembling in between Rickie Lee Jones and Carole King, and little bit through the nose. The CD sounds like an unplugged record. I wonder if the songs are Jazz, Country, Folk or all mixed up. I feel that she has her weak "own character." Yeah, anyhow, the songs are well matching for the light drinks in the lounge with some friends, and the violin cries as if to describe liquid eyes of the girl singing I've Got to See You Again. Not only this, but my Monolithic SuSy amp also does not miss the musical energy of Nickelback Siver side up.
I agree that Class A amps in general give us better sounds than Class A/B or B amps. Nevertheless, I am building two more ships, Monolithic SuSy, to complete total 6 channels.
JH
Wish you to fill up the whole space successfully.
Netlist,
Could you please post the schematic you used or atleast point to the location where it is available. I am about to start building an Aleph-X and am interested in the TL431CLP as the current sourcel; it should certainly have a lot lesser noise than a zener/ mosfet combination current source. Thanks.
Could you please post the schematic you used or atleast point to the location where it is available. I am about to start building an Aleph-X and am interested in the TL431CLP as the current sourcel; it should certainly have a lot lesser noise than a zener/ mosfet combination current source. Thanks.
Hi, SamSamuel Jayaraj said:
Thanks for your interest
The TL431 schematic I used is here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=9635
The rest of the amp is Grey's schematic: Except with 16 instead of 4 output devices, 0.47ohm source resistors, 220k feedback.
/Hugo
A bit of hum in the industry.
Still fine-tuning that nice amp, I noticed a quite annoying 100Hz hum at the output.
When measuring the absolute AC voltage, that is from OUT+ to ground and from OUT- to ground, the OUT+ side gives about 28mVAC and the OUT- about 2mVAC.
This results in about 30mVAC differential AC at 100Hz.
Because its 100Hz I assume it comes from the power supply.
The only thing I can't understand is the difference at both sides of the amp.
I still use it single ended. Even with input shorted the hum doesn't change.
The ripple of the power supply is 250mV, which is not that bad.
Still a little bit more than 10% is present at the OUT+
Anyone had the same experience or can someone give me a hint?
/Hugo
Still fine-tuning that nice amp, I noticed a quite annoying 100Hz hum at the output.
When measuring the absolute AC voltage, that is from OUT+ to ground and from OUT- to ground, the OUT+ side gives about 28mVAC and the OUT- about 2mVAC.
This results in about 30mVAC differential AC at 100Hz.
Because its 100Hz I assume it comes from the power supply.
The only thing I can't understand is the difference at both sides of the amp.
I still use it single ended. Even with input shorted the hum doesn't change.
The ripple of the power supply is 250mV, which is not that bad.
Still a little bit more than 10% is present at the OUT+
Anyone had the same experience or can someone give me a hint?
/Hugo
I also have some hum and noticed that matching input coupling caps is one way to slightly lower it, but it doesn't go completely.
The other thing I noticed that right after start the hum is not present and it comes only after a second or two. Since I'm using thermistors, I believe it happens after they warm up and resistance drops, so less filtering is provided. I'm using the same grounding scheme as I had in A75 (which was modified into Aleph X) so I don't suspect grounding problems to create hum. It's probably not enough filtering. If I remeber correctly, I'm using 100,000u per channel.
The other thing I noticed that right after start the hum is not present and it comes only after a second or two. Since I'm using thermistors, I believe it happens after they warm up and resistance drops, so less filtering is provided. I'm using the same grounding scheme as I had in A75 (which was modified into Aleph X) so I don't suspect grounding problems to create hum. It's probably not enough filtering. If I remeber correctly, I'm using 100,000u per channel.
Hi ,
On my Aleph X prototype I can hear almost no hum close to the speaker.Ear on it . Speaker efficiency is 96 dB/W.
The proto runs at 22.6 V actually , at 4.25 A total bias .
I have 2 toroids each 2 X 20 V 500 VA , 2 rectifier bridges , then parallel . Filtering is only 8 X 22.000 uF.arranged in a symetric C-R-C with 3.9 ohms 17W 4 resistors wired in parallel for each rail .
I have differential DC at about 40 mV stays still.
On turn on absolute DC is 2-3 V and goes down to +/- 120 mV after warm up,and moves a little up and down .
The resistors go hot but within limits.I would say 70 degrees,as they are cement 17 W types I don't bother.
Please e-mail me for details if needed.
Regards
Anael
PS no earth connection at ground.Currently made on the other block,left channel , an Aleph 4
Sound is different but same family ,so I have to go on working...
On my Aleph X prototype I can hear almost no hum close to the speaker.Ear on it . Speaker efficiency is 96 dB/W.
The proto runs at 22.6 V actually , at 4.25 A total bias .
I have 2 toroids each 2 X 20 V 500 VA , 2 rectifier bridges , then parallel . Filtering is only 8 X 22.000 uF.arranged in a symetric C-R-C with 3.9 ohms 17W 4 resistors wired in parallel for each rail .
I have differential DC at about 40 mV stays still.
On turn on absolute DC is 2-3 V and goes down to +/- 120 mV after warm up,and moves a little up and down .
The resistors go hot but within limits.I would say 70 degrees,as they are cement 17 W types I don't bother.
Please e-mail me for details if needed.
Regards
Anael
PS no earth connection at ground.Currently made on the other block,left channel , an Aleph 4
Sound is different but same family ,so I have to go on working...
Peter,
With input coupling caps bypassed, the hum increases from 30 to 33mV. So, indeed that's correct.
I tried all different grounding schemes without any improvement so this will not be the cause as well.
I currently use 272.000uF and guess that must be enough.
Did you ever measure (or could you do it in time) the difference in hum between both halves of the amp?
This is the most mysterious part. Like I said, one halve is almost perfect, the other one produces the hum.
I also noticed the hum increases with higher bias and vice versa.
Nar, could you also try to measure the difference in hum on both halves?
Must be in the very low mV range if you can't hear it.
/Hugo
With input coupling caps bypassed, the hum increases from 30 to 33mV. So, indeed that's correct.
I tried all different grounding schemes without any improvement so this will not be the cause as well.
I currently use 272.000uF and guess that must be enough.
Did you ever measure (or could you do it in time) the difference in hum between both halves of the amp?
This is the most mysterious part. Like I said, one halve is almost perfect, the other one produces the hum.
I also noticed the hum increases with higher bias and vice versa.
Nar, could you also try to measure the difference in hum on both halves?
Must be in the very low mV range if you can't hear it.
/Hugo
I found a bad soldering on my driver board, which caused the 28mV hum on one side.
Now, the hum on both halves is reduced to 9.5mV, which is still audible but much better.
Now if I could reduce that 9.5mV to almost zero, this would make the best sounding amp I ever heard.
I'm absolutely impressed with the sound!!!
/Hugo
Now, the hum on both halves is reduced to 9.5mV, which is still audible but much better.
Now if I could reduce that 9.5mV to almost zero, this would make the best sounding amp I ever heard.
I'm absolutely impressed with the sound!!!
/Hugo
Netlist said:I found a bad soldering on my driver board, which caused the 28mV hum on one side.
Now, the hum on both halves is reduced to 9.5mV, which is still audible but much better.
Now if I could reduce that 9.5mV to almost zero, this would make the best sounding amp I ever heard.
I'm absolutely impressed with the sound!!!
/Hugo
Do you measure with shorted input or with a open one? Do you use single ended or balanced? You did use input caps didn't you? So when you short, you short the single ended tulip plug with the caps in place?
When you explain me your procedure I can measure the same on my channels!
Edwin
Netlist,
Congratulations ! Seems you are now close to perfection,with so little hum on the speakers.
One way to improve it would maybe to throw away some ripple.As you have much capacitors you can probably try it.
Just add Rs into a CRCRCRC configuration,to have a multiple hum-killing effect.Just use ohm law to calculate the voltage drops and power requirements for the resistors.At least,if you have 3-4 V reserve to divide in 3 to give you voltage drops against bias current,that maybe works.I don't know,just try it.
One other thing to get lowest output noise with the Aleph X is certainly to drive it BALANCED.With unbalanced operation the amp works , but not with lowest noise level possible.
In case you drive it UNBALANCED,shorting the - input to ground at the input of the amp may not be the best solution.
If you know precisely the output impedance of your pre-amp,then you can
Use a XLR 3 for the input of the amp.
Use 3 wire balanced cable to plug it in.3 terminations at this end + - ground.
At the other end of the cable ( i.e. your pre output!) use a RCA,and + goes to hot , ground to cold and - is wired to ground through appropriate resistor ( i.e. same value as your preamp's output impedance)
That way using passive balanced connection might improve hum on your Aleph -X .I don't know.Give it a try !!! That might work better than only shorting - in of the amp to ground
Try it and let me know how it works .
Regards
Anael
Congratulations ! Seems you are now close to perfection,with so little hum on the speakers.
One way to improve it would maybe to throw away some ripple.As you have much capacitors you can probably try it.
Just add Rs into a CRCRCRC configuration,to have a multiple hum-killing effect.Just use ohm law to calculate the voltage drops and power requirements for the resistors.At least,if you have 3-4 V reserve to divide in 3 to give you voltage drops against bias current,that maybe works.I don't know,just try it.
One other thing to get lowest output noise with the Aleph X is certainly to drive it BALANCED.With unbalanced operation the amp works , but not with lowest noise level possible.
In case you drive it UNBALANCED,shorting the - input to ground at the input of the amp may not be the best solution.
If you know precisely the output impedance of your pre-amp,then you can
Use a XLR 3 for the input of the amp.
Use 3 wire balanced cable to plug it in.3 terminations at this end + - ground.
At the other end of the cable ( i.e. your pre output!) use a RCA,and + goes to hot , ground to cold and - is wired to ground through appropriate resistor ( i.e. same value as your preamp's output impedance)
That way using passive balanced connection might improve hum on your Aleph -X .I don't know.Give it a try !!! That might work better than only shorting - in of the amp to ground
Try it and let me know how it works .
Regards
Anael
Edwin,
Whether I short the inputs or not, the hum stays the same. Because it's 100Hz it comes from the PSU, so IMO it has nothing to do with grounds or inputs.
I'm getting more and more convinced that the CRCRC option could bring the solution. As I only have four caps of 68.000µF it will be CRC. Maybe a CLC would be better (and more expensive) then.
Arne, I'm not sure what you want to say.
Nar, I will study your recommendations and let you know.
/Hugo
Whether I short the inputs or not, the hum stays the same. Because it's 100Hz it comes from the PSU, so IMO it has nothing to do with grounds or inputs.
I'm getting more and more convinced that the CRCRC option could bring the solution. As I only have four caps of 68.000µF it will be CRC. Maybe a CLC would be better (and more expensive) then.
Arne, I'm not sure what you want to say.
Nar, I will study your recommendations and let you know.
/Hugo
Sorry for not helping,
But I have a pair A-X boards finished, and just wonder if it's worth buying a caps, ribs/chassi + super-large trafo, that hardly can be used for anything else? ( In case I do not like the result / endless hum-problems...).
Well, I could probably use the trafo for a 10+ channel GainClone if it does not work out.....
(Damn 24% import tax + handeling fees make the missing parts so expensive, that they has to be put on use, one way or another).
Arne K
But I have a pair A-X boards finished, and just wonder if it's worth buying a caps, ribs/chassi + super-large trafo, that hardly can be used for anything else? ( In case I do not like the result / endless hum-problems...).
Well, I could probably use the trafo for a 10+ channel GainClone if it does not work out.....
(Damn 24% import tax + handeling fees make the missing parts so expensive, that they has to be put on use, one way or another).
Arne K
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