Heat Generation
I am still messing with my first one. I wish the camera would take pics low rez enough to post. But one thing, my heatsinks barely get warm.
I do not know if this good or bad. One thing, I used 0.01% resistors for the 22K and 47K. This MAY help it to generate less heat idling. It has never been hooked up to my speakers, they are single drivers that cannot handle a lot of dc or power. Waiting till the unit is working as I like it to really test. It has only been hooked up to some cheap speakers to see if it plays and check for hum. I have yet to play a whole song through.
George
I am still messing with my first one. I wish the camera would take pics low rez enough to post. But one thing, my heatsinks barely get warm.
I do not know if this good or bad. One thing, I used 0.01% resistors for the 22K and 47K. This MAY help it to generate less heat idling. It has never been hooked up to my speakers, they are single drivers that cannot handle a lot of dc or power. Waiting till the unit is working as I like it to really test. It has only been hooked up to some cheap speakers to see if it plays and check for hum. I have yet to play a whole song through.
George
My heat sink never gets hot either. Are there any other problems you are seeing that are keeping you from trying it out for real?
Worried
I am worried about a measured voltage. Measuring the metal tab on the LM3886 to ground I get a variation in this voltage from one chip to the other. Is this normal? This is my first stab at chip amps.
Hope to rerun some wires this weekend and get it settled in main system soon.
George
BrianDonegan said:
I am worried about a measured voltage. Measuring the metal tab on the LM3886 to ground I get a variation in this voltage from one chip to the other. Is this normal? This is my first stab at chip amps.
Hope to rerun some wires this weekend and get it settled in main system soon.
George
Re: Worried
Yes its normal to get DC there, the tab carries the negative rail, if you are using the T package. Though the variance sort of confuses me...
Panelhead said:
Yes its normal to get DC there, the tab carries the negative rail, if you are using the T package. Though the variance sort of confuses me...
The tab is electrically isolated from the case, right? If not, your case (or heatsink) has rail voltage. That would be bad, but may explain the fluctuation.
Re: Heat Generation
Another option is Picasa - it's a photo management software for windows by google that works somewhat like iPhoto does on the mac. I've switched a few people who were having dramas with the oem software to it, and they're loving it.
http://picasa.google.com/index.html
Some cameras come with a light version of photoshop, that works well too. A lot of the oem software is pretty klunky.
Michael
Panelhead said:
Another option is Picasa - it's a photo management software for windows by google that works somewhat like iPhoto does on the mac. I've switched a few people who were having dramas with the oem software to it, and they're loving it.
http://picasa.google.com/index.html
Some cameras come with a light version of photoshop, that works well too. A lot of the oem software is pretty klunky.
Michael
Re: Re: Worried
Me too, one is at -34, the other at -29! Why I DO NOT KNOW. They should be the same.
I suspect a problem with the LM3886. Or the connections. The LM3886T are isolated with mica and paste. The chips and the heatsinks are not hot, but the 1000 ohm dropping resistors will tatoo you. Checking the whole board is isolated from the case.
Rather than clip leads and replace the suspect LM3886 I am going to build another board. I learned a little on the first one, this one should be better.
George
Russ White said:
Me too, one is at -34, the other at -29! Why I DO NOT KNOW. They should be the same.
I suspect a problem with the LM3886. Or the connections. The LM3886T are isolated with mica and paste. The chips and the heatsinks are not hot, but the 1000 ohm dropping resistors will tatoo you. Checking the whole board is isolated from the case.
Rather than clip leads and replace the suspect LM3886 I am going to build another board. I learned a little on the first one, this one should be better.
George
Re: Re: Heat Generation
Maf_au has a good point
Use Picasa to email the picture to yourself. It will compress the picture for you.
maf_au said:
Maf_au has a good point
Use Picasa to email the picture to yourself. It will compress the picture for you.
Re: 4 channel "my ref" almost ready ...
Excellent work!!! 😀 I like it.
SmellOfPoo said:that far i am ... now hurry and get some interconnects.hope it will keep on raining and my girlfriend is busy over the weekend. 😉 plugged out telephone, doorbell is disabled. more pictures to come if you like.
Excellent work!!! 😀 I like it.
Well, I have been burning these puppies in all day. I wish I could invite you all into my living room to hear the results! Wow! I don't know what exactly changed (remember there are a couple of subtle changes in my circuit, like bypass caps to GND besides those accross the rails on by opamps) but this is not the REV C I remember(which I did not like as much as Rev A).
I am listening to them on my Tannoys right now (about 6 ohm) and this is nice combo... Wow very revealing, but not at all harsh or hard on the ears, I could sit here and listen for hours(well I have actually🙂) without fatigue. I think the better phase coherance is more evident than I remebered. This comes through in complex passages where instruments don't loose their place in the room, or sound muffled or sloppy.
I would very easily recommend this amp over my aleph, though not by a large margine, but the sound is quite a lot a like. This is a compliment to the aleph! 😀
Just a couple of tweaks to the silkscreen and larger pads for 1 cap and this puppy is going to the PCB manufacturer. 🙂
I did not get enough REV As and a lot of people missed out, I will order more of these.
Remember you can build this PCB REV A,B or C. I am going to build another two of these Rev A tomorrow for head to head tests, but honestly I don't think it is all that close. I feel like a REV C convert! 😀
Cheers!
Russ
I am listening to them on my Tannoys right now (about 6 ohm) and this is nice combo... Wow very revealing, but not at all harsh or hard on the ears, I could sit here and listen for hours(well I have actually🙂) without fatigue. I think the better phase coherance is more evident than I remebered. This comes through in complex passages where instruments don't loose their place in the room, or sound muffled or sloppy.
I would very easily recommend this amp over my aleph, though not by a large margine, but the sound is quite a lot a like. This is a compliment to the aleph! 😀
Just a couple of tweaks to the silkscreen and larger pads for 1 cap and this puppy is going to the PCB manufacturer. 🙂
I did not get enough REV As and a lot of people missed out, I will order more of these.
Remember you can build this PCB REV A,B or C. I am going to build another two of these Rev A tomorrow for head to head tests, but honestly I don't think it is all that close. I feel like a REV C convert! 😀
Cheers!
Russ
Pictures, I think
I am new to posting pictures, so hope this turns out. Finally had some time to put the case on. Continue to be amazed at this little amp. Detail and clarity. Have not seen the heat problems others talk about. .1% resistors where specified. 3 watts for the 1k's and splurged on the caps.
I am new to posting pictures, so hope this turns out. Finally had some time to put the case on. Continue to be amazed at this little amp. Detail and clarity. Have not seen the heat problems others talk about. .1% resistors where specified. 3 watts for the 1k's and splurged on the caps.
Attachments
Up and playing
Built a new board yesterday. Got the amp playing this morning. It is the Rev A.
Like the sound, it seems rich and full. Gets the tonallity right, along with timbre. Lots of punch.
My speakers may not be optimal, 15 ohm, 100 dB efficient. The amp is pllaying at mW levels. The noise level is very low, measured 0.0 mv ac hum on initial check out. This required a little lead dressing, the speakers cables and input cable run right over the SIP bridge rectifiers.
I tried dowloading the image software, but only got down to 470K from the original 2.5 meg sizes. If someone more savy is willing I
Built a new board yesterday. Got the amp playing this morning. It is the Rev A.
Like the sound, it seems rich and full. Gets the tonallity right, along with timbre. Lots of punch.
My speakers may not be optimal, 15 ohm, 100 dB efficient. The amp is pllaying at mW levels. The noise level is very low, measured 0.0 mv ac hum on initial check out. This required a little lead dressing, the speakers cables and input cable run right over the SIP bridge rectifiers.
I tried dowloading the image software, but only got down to 470K from the original 2.5 meg sizes. If someone more savy is willing I
Up and playing
Built a new board yesterday. Got the amp playing this morning. It is the Rev A.
Like the sound, it seems rich and full. Gets the tonallity right, along with timbre. Lots of punch.
My speakers may not be optimal, 15 ohm, 100 dB efficient. The amp is pllaying at mW levels. The noise level is very low, measured 0.0 mv ac hum on initial check out. This required a little lead dressing, the speakers cables and input cable run right over the SIP bridge rectifiers.
I tried dowloading the image software, but only got down to 470K from the original 2.5 meg sizes. If someone more savy is willing I
Built a new board yesterday. Got the amp playing this morning. It is the Rev A.
Like the sound, it seems rich and full. Gets the tonallity right, along with timbre. Lots of punch.
My speakers may not be optimal, 15 ohm, 100 dB efficient. The amp is pllaying at mW levels. The noise level is very low, measured 0.0 mv ac hum on initial check out. This required a little lead dressing, the speakers cables and input cable run right over the SIP bridge rectifiers.
I tried dowloading the image software, but only got down to 470K from the original 2.5 meg sizes. If someone more savy is willing I