Hi there!
He berry, they are both working now, the channels, it was not much what was wrong, but one part can do anything wrong, from the left channel it was only Q5 and from the other it was only the 1 ohm resistor only now we have to try it with loudpeaker on it and measering if there is difference between the channels. The transformers are realy loud humming. We wil see what we can do on it. I'll let you know. I am a happy guy now.
He berry, they are both working now, the channels, it was not much what was wrong, but one part can do anything wrong, from the left channel it was only Q5 and from the other it was only the 1 ohm resistor only now we have to try it with loudpeaker on it and measering if there is difference between the channels. The transformers are realy loud humming. We wil see what we can do on it. I'll let you know. I am a happy guy now.
Teake,
That's the best news in weeks. 😎
Congrats.
What transformers and VA ratings did you use?
/Hugo
That's the best news in weeks. 😎
Congrats.
What transformers and VA ratings did you use?
/Hugo
Hi Netlist!
Thanks for your reply. I use dubbel mono, two trafo's from 300VA,
2x25v, 6 amp each, one bridge rectifier for each mono-side, for each mono-side i got 2 x 47000UF. On both rails I got 32volt.
greetings Teake
Thanks for your reply. I use dubbel mono, two trafo's from 300VA,
2x25v, 6 amp each, one bridge rectifier for each mono-side, for each mono-side i got 2 x 47000UF. On both rails I got 32volt.
greetings Teake
Would you think the hum is related to the current they deliver?
Do they hum when you disconnected the secondaries?
/Hugo
Do they hum when you disconnected the secondaries?
/Hugo
Hi,
you could try a dc filter for your transformers (helped in my Aleph 5 (600VA trannies, 25V, 2.5A bias)).
If this doesn´t help you can try to decouple them mechanically.
If this doesn´t help you are as far as I am in my Aleph-X and will probably have to buy new (bigger and better) transformers or place your amps in another room.....
William
you could try a dc filter for your transformers (helped in my Aleph 5 (600VA trannies, 25V, 2.5A bias)).
If this doesn´t help you can try to decouple them mechanically.
If this doesn´t help you are as far as I am in my Aleph-X and will probably have to buy new (bigger and better) transformers or place your amps in another room.....
William
What transformers do you use (amplimo/conrad). I use the schuro transformes (Germany), but they also make a humming sound. I also use a DC filter, but without succes.
How can you decouple them mechanically ?
How can you decouple them mechanically ?
1) I was also going to ask what does it mean by mechanically decouple the transformers? Would installing transformers on steel chassis causes more hum?
2) DC filters ... that is to be installed on the primary side of the transformers, right? Any example (link?, pictures?) of a commercially available DC filters?
2) DC filters ... that is to be installed on the primary side of the transformers, right? Any example (link?, pictures?) of a commercially available DC filters?
http://www.euronet.nl/~mgw/homepage/uk_index.html
Nice link in dutch and englisch for diy cabel filters !
Nice link in dutch and englisch for diy cabel filters !
hi there!
U use ILP transformers, I found out that they got the same configuration as Amplimo and Plitron. Two pink primary and 4 secundary, from wich I used two to connect to the bridgerectifier and the other two to the floating ground, wich is connected with a cl60 thermister to chassis ground. I have two schaffner dc filters but dit not use them yet. Would it be better? And can I put them on the transformers?
Thanks allready. Greetings Teake.
U use ILP transformers, I found out that they got the same configuration as Amplimo and Plitron. Two pink primary and 4 secundary, from wich I used two to connect to the bridgerectifier and the other two to the floating ground, wich is connected with a cl60 thermister to chassis ground. I have two schaffner dc filters but dit not use them yet. Would it be better? And can I put them on the transformers?
Thanks allready. Greetings Teake.
Again Hi!
I know when we put the amplifier on the oscilloscope and want to get more gain the transformers are getting louder humming.
I know when we put the amplifier on the oscilloscope and want to get more gain the transformers are getting louder humming.
Hi,
decoupling mechanically means that you see to it that the hum isn´t amplified by boards or chassis parts. This means you will only hear the humm the is directly comming from the transformer (by air)
The easiest way to do this is by placing it on a soft sheet of rubber or use rubber silent blocks to mount the transformer. I
William
decoupling mechanically means that you see to it that the hum isn´t amplified by boards or chassis parts. This means you will only hear the humm the is directly comming from the transformer (by air)
The easiest way to do this is by placing it on a soft sheet of rubber or use rubber silent blocks to mount the transformer. I
William
Thanks William!
You never know what happened. He's playing, and HOW! WOW
What a sound! Only when I put the amplifier on there is a loud humming from the transformer for a while, suddenly it dissepears and there is only some 50hz humming from the speakers, you can,t hear it from 2 meters but when you put the ear close to the loudspeaker you can! Tomorrow I will try to do something with wireing or put a cupper plate between the powersupply and the pcb, mayby that helps. Some of you got other ideas? Let me hear, and thanks again for the support.
Greetings teake
You never know what happened. He's playing, and HOW! WOW
What a sound! Only when I put the amplifier on there is a loud humming from the transformer for a while, suddenly it dissepears and there is only some 50hz humming from the speakers, you can,t hear it from 2 meters but when you put the ear close to the loudspeaker you can! Tomorrow I will try to do something with wireing or put a cupper plate between the powersupply and the pcb, mayby that helps. Some of you got other ideas? Let me hear, and thanks again for the support.
Greetings teake
Hi intense-tavda,
Congratulations!
The loud humming from the transformer on startup has to do with the start-up sequence. You did install the NTC resistor I presume?
I had the same trouble, and developed a soft-start circuit, where I startup the transformer with a 100 ohm resistor value in series. Check the board, there are plenty of examples. Will present my own board in a few days.
The 50 hz from the speaker. Are you sure it is 50 hz and not 100 hz? That is what I would expect from your power supply.
100 Hz can be eliminated with a coil between your capacitors. (See Kristians design earlier in the thread).
Reducing the 50 Hz is very difficult with a copper shielding. I use Mu-metal, and bought an experiment set from www.magnetic-shield.com. (has a Dutch dealer). This set has a measurement kit that shows you quickly what the result of a shielding will be.
I did not do this in my Aleph 5.
Greetings, Harry
Congratulations!
The loud humming from the transformer on startup has to do with the start-up sequence. You did install the NTC resistor I presume?
I had the same trouble, and developed a soft-start circuit, where I startup the transformer with a 100 ohm resistor value in series. Check the board, there are plenty of examples. Will present my own board in a few days.
The 50 hz from the speaker. Are you sure it is 50 hz and not 100 hz? That is what I would expect from your power supply.
100 Hz can be eliminated with a coil between your capacitors. (See Kristians design earlier in the thread).
Reducing the 50 Hz is very difficult with a copper shielding. I use Mu-metal, and bought an experiment set from www.magnetic-shield.com. (has a Dutch dealer). This set has a measurement kit that shows you quickly what the result of a shielding will be.
I did not do this in my Aleph 5.
Greetings, Harry
Hi guys!
Last days I was with a friend and he has a oscilloscoop, when it was clear that the amplifier was ready I took him home. I placed the pcb's at the heatsinks with some distencespacers from about 3 centimeters and got the amplifier on power again, I did not connect any pre or cdplayer only the speakers. I could not hear any humming from the transformers anymore, only some little humming from the speakers. I only could hear it with my ear on the speakers, not one meter in front of it. And measured the outputvoltages. Now I got 00,1v on one side end on the other I got 00,18V, is this allright or does it has to be the same?
And the heatsinks are real getting hot, I can't put my hand on it till about 10 seconds. Is this oke? I will measure it tomorrow.
Can I put a cd player and pre on it now? Thanks for everything till now! Greetings Teake.
Last days I was with a friend and he has a oscilloscoop, when it was clear that the amplifier was ready I took him home. I placed the pcb's at the heatsinks with some distencespacers from about 3 centimeters and got the amplifier on power again, I did not connect any pre or cdplayer only the speakers. I could not hear any humming from the transformers anymore, only some little humming from the speakers. I only could hear it with my ear on the speakers, not one meter in front of it. And measured the outputvoltages. Now I got 00,1v on one side end on the other I got 00,18V, is this allright or does it has to be the same?
And the heatsinks are real getting hot, I can't put my hand on it till about 10 seconds. Is this oke? I will measure it tomorrow.
Can I put a cd player and pre on it now? Thanks for everything till now! Greetings Teake.
Teake,
If you read 0.18V and 0.1V that would be 180 and 100 millivolt.
Not bad but aiming for less then 100mV would be better. That is the voltage measured on the +Out and - Out or at the speaker terminals if you wish. Give the amp sufficient time to settle, i.e. +1hour.
Edit: No +Out or -Out, just the output to ground; I confused with AlephX.
/Hugo 🙂
If you read 0.18V and 0.1V that would be 180 and 100 millivolt.
Not bad but aiming for less then 100mV would be better. That is the voltage measured on the +Out and - Out or at the speaker terminals if you wish. Give the amp sufficient time to settle, i.e. +1hour.
Edit: No +Out or -Out, just the output to ground; I confused with AlephX.
/Hugo 🙂
Teake,
if you can hold your hand on your heatsinks for longer than 10 seconds you bias is too low😀
😀
Like Hugo said, 180mV is a bit too much. Did you match your input fets?
William
if you can hold your hand on your heatsinks for longer than 10 seconds you bias is too low😀
😀 Like Hugo said, 180mV is a bit too much. Did you match your input fets?
William
He thanks guys.
I did match my mosfets.
I just played some music, it sounds great! Dynamic, spaceful, and warm but also analytical. beautiful. How can I lower the output William? Or get the left and right channel matched? And can it get any harm? Teake
I did match my mosfets.
I just played some music, it sounds great! Dynamic, spaceful, and warm but also analytical. beautiful. How can I lower the output William? Or get the left and right channel matched? And can it get any harm? Teake
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