vertiges
Well-known member
Hi,
I'm building API 312 clone on a prototyping board (which is very painful).
I'm following this schematic :
I use a Cinemag CM-75101APC with a RL of 150k. (I omitted R4, C5, C7 and RL is between (4) and the IN+ of the 2520.)
And a CMOQ-2S for the output tx.
I use the 2520 clone from Peter Purpose under +/- 16.65 volts.
(It's the 2520 which is under voltage, not Peter... :green: )
As usual, I'm "diy-ing" when I have time... the night ! :wink:
I was tired, so I made a few "mistakes" :
1) I forgot to link the ground pin of the 2520 to the ground. :roll:
2) I didn't use the C3 at the beginning.
3) Ah, yes, probably the worth, I had a 68 Ohms between the HI and the LOW of the output TX. It was a part of a attenuator I forgot to disconnect.
Before fixing the problems above (I've never be able to get make the preamp work), I noticed there was a transistor (the metallic one above the out pin) which was getting VERY hot in 15-20 seconds. I noticed it very quickly, so I swiched off the PSU. So the 2520 has never been under power more than 30 seconds.
I've checked, re-cheked and re-re-re-rechecked everything, corrected my mistakes and now, I'm testing it again :
At the IN+ I have between 150mV and 350 mV when I speak in front of a SM57.
At the output of the CMOQ-2S, the sound is thin and distorted.
The gain doesn't work at all. It makes the sound of a "blurry" buzz when I turn it, but that sound goes away when I stop turning it. (Do you follow me ? :green: ) I use a 20k rev log from JLM with a R2=270 Ohms
And again the transistor (btw, is it a transistor ?), the metallic one above the out pin, is getting very hot in 15-20 seconds.
Is it dead ? There is no external sign of burning and it doesn't smell like roasted plastic.
How fast is it possible to destroy a 2520 ?
Is there any simple way to test it ?
Thank you,
eD)))
I'm building API 312 clone on a prototyping board (which is very painful).
I'm following this schematic :
I use a Cinemag CM-75101APC with a RL of 150k. (I omitted R4, C5, C7 and RL is between (4) and the IN+ of the 2520.)
And a CMOQ-2S for the output tx.
I use the 2520 clone from Peter Purpose under +/- 16.65 volts.
(It's the 2520 which is under voltage, not Peter... :green: )
As usual, I'm "diy-ing" when I have time... the night ! :wink:
I was tired, so I made a few "mistakes" :
1) I forgot to link the ground pin of the 2520 to the ground. :roll:
2) I didn't use the C3 at the beginning.
3) Ah, yes, probably the worth, I had a 68 Ohms between the HI and the LOW of the output TX. It was a part of a attenuator I forgot to disconnect.
Before fixing the problems above (I've never be able to get make the preamp work), I noticed there was a transistor (the metallic one above the out pin) which was getting VERY hot in 15-20 seconds. I noticed it very quickly, so I swiched off the PSU. So the 2520 has never been under power more than 30 seconds.
I've checked, re-cheked and re-re-re-rechecked everything, corrected my mistakes and now, I'm testing it again :
At the IN+ I have between 150mV and 350 mV when I speak in front of a SM57.
At the output of the CMOQ-2S, the sound is thin and distorted.
The gain doesn't work at all. It makes the sound of a "blurry" buzz when I turn it, but that sound goes away when I stop turning it. (Do you follow me ? :green: ) I use a 20k rev log from JLM with a R2=270 Ohms
And again the transistor (btw, is it a transistor ?), the metallic one above the out pin, is getting very hot in 15-20 seconds.
Is it dead ? There is no external sign of burning and it doesn't smell like roasted plastic.
How fast is it possible to destroy a 2520 ?
Is there any simple way to test it ?
Thank you,
eD)))