hi brian,
thanks for the response,
this happens even when the overall volume is not too high with a set of full sized headphones.....if the amp is clipping would the dc offset also go wild, i.e. swing between + and - 50mv? i can reduce the gain on the cmoy if you think this is the problem...
thanks for the response,
this happens even when the overall volume is not too high with a set of full sized headphones.....if the amp is clipping would the dc offset also go wild, i.e. swing between + and - 50mv? i can reduce the gain on the cmoy if you think this is the problem...
back again,
nelsonvandal,im using 2 9volt batteries in series for each channel,
anyway i removed the cmoy, and now i just have a 10k pot at the input of the diamante...
i think my offset trimpot was bad because i was reading <5mv offset but hearing distortion....i turned the trimpot, the offset went high and then after a few more turns went back down to <5mv, this time without distortion...
managed to get both channels distortion free,
im measuring 20mv across the emitter resistors..and the amp sounds good to me at this level of bias.
if i turn the volume all the way up, to uncomfortable levels then i hear distortion, again probably clipping, i might reduce the gain a little, right now the amp has a gain of 3.5
thanks for all the help guys...
mymindinside
p.s. if im using seperate batteries for the left and right channels, do i need to connect the power grounds (the middle pin in the 3pin connector on the pcb) of the 2 channels together?
nelsonvandal,im using 2 9volt batteries in series for each channel,
anyway i removed the cmoy, and now i just have a 10k pot at the input of the diamante...
i think my offset trimpot was bad because i was reading <5mv offset but hearing distortion....i turned the trimpot, the offset went high and then after a few more turns went back down to <5mv, this time without distortion...
managed to get both channels distortion free,
im measuring 20mv across the emitter resistors..and the amp sounds good to me at this level of bias.
if i turn the volume all the way up, to uncomfortable levels then i hear distortion, again probably clipping, i might reduce the gain a little, right now the amp has a gain of 3.5
thanks for all the help guys...
mymindinside
p.s. if im using seperate batteries for the left and right channels, do i need to connect the power grounds (the middle pin in the 3pin connector on the pcb) of the 2 channels together?
Work still in progress... 
I'm encountering balance result trouble after puting my Diamante in the enclosure.
What is connected to the box :
- 2 x RCA plugs - Isolated
- IEC socket EU standard 3 pins - Ground pin connected to chassis
- Alps Rk27 10K log - Not isolated
- 6.5mm Jack Socket - Not isolated
- PSU & Diamante PCB screwed with spacers - Isolated with PCB
Facts
Left channel down when the Jack is socketed to the chassis.
Inverting L/R RCA inputs gives the same result.
Both channels are Ok when the Jack is not in contact with the box.
When the Jack is in contact with the chassis/box, one channel goes down.
Your suggestions are welcome... newbie inside
Thanks !
Optional but needed
1° - More Output Power
I'm using a HD-650 ans I need more output power.
Which R values to increase ?
2° - Volume
Power seems to be delivered at the end of the 10K pot curse.
In this area, the sound/music seems to be more "complete".
I mean that whole details can't be eared at low volume.
Will this lack be reduced by increasing output power ?
I'm encountering balance result trouble after puting my Diamante in the enclosure.
What is connected to the box :
- 2 x RCA plugs - Isolated
- IEC socket EU standard 3 pins - Ground pin connected to chassis
- Alps Rk27 10K log - Not isolated
- 6.5mm Jack Socket - Not isolated
- PSU & Diamante PCB screwed with spacers - Isolated with PCB
Facts
Left channel down when the Jack is socketed to the chassis.
Inverting L/R RCA inputs gives the same result.
Both channels are Ok when the Jack is not in contact with the box.
When the Jack is in contact with the chassis/box, one channel goes down.
Your suggestions are welcome... newbie inside
Thanks !
Optional but needed
1° - More Output Power
I'm using a HD-650 ans I need more output power.
Which R values to increase ?
2° - Volume
Power seems to be delivered at the end of the 10K pot curse.
In this area, the sound/music seems to be more "complete".
I mean that whole details can't be eared at low volume.
Will this lack be reduced by increasing output power ?
As for gain, see this post:
http://www.diyaudio.com/forums/showthread.php?postid=1582650#post1582650
What gain are you running now?
http://www.diyaudio.com/forums/showthread.php?postid=1582650#post1582650
What gain are you running now?
Thank to all of you for your kind support !
When the jack is isolated (out of the case) the sound is Ok.
The problem is when the jack is screwed on the front panel.
One chanel goes down and is mute, the volume on the other chanel is very low...
Thank's Aparatusonitus for the tip, I'll give a look at the wiring.
I think you've found the trouble...
Thank you Russ for the Gain.
The formula is : G = (RF / RG) +1
I've used standards values as show by Mr Majestic.
I've to check the values.
I'll try your recommandations on Tuesday and let you know about it !
Cheers !
When the jack is isolated (out of the case) the sound is Ok.
The problem is when the jack is screwed on the front panel.
One chanel goes down and is mute, the volume on the other chanel is very low...
Thank's Aparatusonitus for the tip, I'll give a look at the wiring.
I think you've found the trouble...
Thank you Russ for the Gain.
The formula is : G = (RF / RG) +1
I've used standards values as show by Mr Majestic.
I've to check the values.
I'll try your recommandations on Tuesday and let you know about it !
Cheers !
korben69 said:
Just change R4 to 3k and R3 to 1k and you will have gain of 4.
http://www.diyaudio.com/forums/attachment.php?s=&postid=1550325&stamp=1214705599
avr300 said:
No, I'm still waiting for both prototype builders to give thumbs up to the board. Of course there is always the possibility of ordering more outside a group buy, but it will cost more. The protypes were €15 euro each. I might be up for getting two more boards myself though to make up a balanced Diamante.
