I finished assembling my RevC boards and began testing them today. They seem to work fine so far. I thought the LM3886 would get much warmer than it does, but it stays only moderately warm. However, I am surprised at how warm the 1k ohm resistors get on the board. Is this normal? I now understand the importance of keeping these resistors elevated above the board.
Although I haven't sat down to critically listen to the amps, I like what I hear. It's pretty gratifying listening to something you made--even if it was just soldering a kit together.
Now, on to the metal casework... (pictures forthcoming)
Although I haven't sat down to critically listen to the amps, I like what I hear. It's pretty gratifying listening to something you made--even if it was just soldering a kit together.
Now, on to the metal casework... (pictures forthcoming)
I couldn't agree with you more.
I've just designed a PCB layout for a simple but very good MC Head Amp ( by Marshall Leach, Jnr.) Granted I am a tad fussy, but it took me an age to do with graph paper. Making the PCB will no doubt take an age as well, and will be inferior to a professional job, such the excellent Twisted Pear boards.
Audie.
bikedude said:
You will probably be fine even with them mounted on the PCB. It is better for them to be lifted 1/2" or so, but it will probably not kill them if they get a bit warmer than usual. I would replace them when you can, but you could run them this way for quite a while, really probably indefinitely.
Humming
I finally completed one channel of my RevC. Powered up without a hitch, relay clicked, etc.
When I connect my test speaker, a *very* noticeable hum starts. I rechecked the connections, moved the trafo around, and changed the input polarity (now the center lead of the RCA goes to the ground input, I suppose that's wrong).
Now the hum is much lower, but the volume is low too.
If I touch the center RCA lead, the hum becomes unnoticeable, and the volume lowers.
If I touch the outer lead, the humming and the volume increases.
Any tips?
I finally completed one channel of my RevC. Powered up without a hitch, relay clicked, etc.
When I connect my test speaker, a *very* noticeable hum starts. I rechecked the connections, moved the trafo around, and changed the input polarity (now the center lead of the RCA goes to the ground input, I suppose that's wrong).
Now the hum is much lower, but the volume is low too.
If I touch the center RCA lead, the hum becomes unnoticeable, and the volume lowers.
If I touch the outer lead, the humming and the volume increases.
Any tips?
I got the full kit from http://www.twistedpearaudio.com/. Excellent quality. They seem to be temporarily out of stock now.
Hi destroyo 
Please check out if your signal ground is connected to chassis: it must not.
Also, power ground goes to PCB only, not chassis.
Excuses if this is all known
Buena suerte!
Mauricio
PS: if it still does humm, check your preamp grounding.
PS2:
Please check out if your signal ground is connected to chassis: it must not.
Also, power ground goes to PCB only, not chassis.
Excuses if this is all known
Buena suerte!
Mauricio
PS: if it still does humm, check your preamp grounding.
PS2:
Yeah! Why do you guys are sooo cruel!
