I have used my ipod, a cell phone, my own laptop all maxed out but the volume on the amp is nowhere near loud as I would expect.
Music quality is excellent though.
What kind of measurments must I perform to debug the board? Is there any obvious mistake in assembly I may have made?
Thanks for the support.
Music quality is excellent though.
What kind of measurments must I perform to debug the board? Is there any obvious mistake in assembly I may have made?
Thanks for the support.
Gain problem
I also built a totaly stock amp with the Edcors and 6JN6's. The only deviation is a 50K PEC pot and I bypassed the coupling caps with Russian teflons. Although not built for them, I am currently listening to them through Proac 2.5's. If I remember correctly this speaker is 87db, so not too efficient. My source is a CD player and the room size is not too large. My normal volume is typically between 12 and 2 oclock depending on the CD and I like my music somewhat loud. I am fairly confident that I would be driven from the room before clipping. So the answer to your question: (is this normal) I think not.
Paul
I also built a totaly stock amp with the Edcors and 6JN6's. The only deviation is a 50K PEC pot and I bypassed the coupling caps with Russian teflons. Although not built for them, I am currently listening to them through Proac 2.5's. If I remember correctly this speaker is 87db, so not too efficient. My source is a CD player and the room size is not too large. My normal volume is typically between 12 and 2 oclock depending on the CD and I like my music somewhat loud. I am fairly confident that I would be driven from the room before clipping. So the answer to your question: (is this normal) I think not.
Paul
I don't think it is normal either. The first board I built was stock except for minor parts substitutions based on junk box availability. The amp would definitely hit clipping when fed from a CD player on most CD's.
Check over your board to make sure that all of the resistors are the correct value.
just checked the resistor values and everything is fine....
I believe the problem is the source....I will try with a cd player and see what happens. Aside from this issure the amp works flawlessly....excellent sound.
The power transformer becomes warm (can keep my hand on it) but everything else is in order.
I might actually build a valve preamp...suggestions?
I believe the problem is the source....I will try with a cd player and see what happens. Aside from this issure the amp works flawlessly....excellent sound.
The power transformer becomes warm (can keep my hand on it) but everything else is in order.
I might actually build a valve preamp...suggestions?
I might actually build a valve preamp...suggestions?
Why yes, yes I do...
A grounded cathode 12B4A with a CCS plate load will do well. Built the CCS from depletion-mode MOSFET's and use the mu output for minimum output impedance. It seems your source level is low by a factor of 2 or 3, so mu of the 12B4 should take care of it well. Consider also type 6AH4 with a mu of 8. either of these can be done with a B+ of ~200V with plate voltage around 120-140( with the rest left over as lots of headroom ).cheers,
Douglas