Playing with my new amplifier for three hours!
I have a small buzzzzzz, I tried to see where is the problem, so when I turn on the amplifier with the speakers connected and the rcas to air I have this buzzzz, when I take of the one rca the buzz stops!!! Any ideas?
I was surprised with the lower spectrum, I listen trough open baffle with an Altec 604-8g, now I have real bass!!!!!
In addition I use FOSTEX T90 a horn super tweeter 106db and first time is so quite not even a hiss... (all others amplifiers I have used, always had some hiss)
The mids also are very very good and clean,stable airy...!!!
The highs i beleive is not in the same level something is missing there, there is no volume, less definition... compared with my sugden the highs are missing!!! Any advice?
I am sure the amplifier need some weeks to burn in!
My f5 use, fairchild mofsets, 300va (talema), 4*47000uf evoxrifa, cheap bridge 35A
I have a small buzzzzzz, I tried to see where is the problem, so when I turn on the amplifier with the speakers connected and the rcas to air I have this buzzzz, when I take of the one rca the buzz stops!!! Any ideas?
I was surprised with the lower spectrum, I listen trough open baffle with an Altec 604-8g, now I have real bass!!!!!
In addition I use FOSTEX T90 a horn super tweeter 106db and first time is so quite not even a hiss... (all others amplifiers I have used, always had some hiss)
The mids also are very very good and clean,stable airy...!!!
The highs i beleive is not in the same level something is missing there, there is no volume, less definition... compared with my sugden the highs are missing!!! Any advice?
I am sure the amplifier need some weeks to burn in!
My f5 use, fairchild mofsets, 300va (talema), 4*47000uf evoxrifa, cheap bridge 35A
Yeah, get used to it
No, honestly, everything is a balance act
And now you have the bass you missed before
Your sudgen do not have better/more highs
Its just relative, and no bass, sounds like more highs, thin and cold
And having that experience with an OB speaker, consider yourself lucky
Yeah, get used to it
No, honestly, everything is a balance act
And now you have the bass you missed before
Your sudgen do not have better/more highs
Its just relative, and no bass, sounds like more highs, thin and cold
And having that experience with an OB speaker, consider yourself lucky
You have to listen a sugden for his extented highs!!!!! I own the baby one A21a, but compared to f5 it's still a baby....!
If the buzz is there with 2 RCA inputs and goes away when
you have one, then it's a ground loop. There are numerous
fixes involving moving and rotating transformers, improving
wiring layout and shielding.
One thing you can do is take the input ground of the RCA on
one channel only and connect it through 10 ohms.
you have one, then it's a ground loop. There are numerous
fixes involving moving and rotating transformers, improving
wiring layout and shielding.
One thing you can do is take the input ground of the RCA on
one channel only and connect it through 10 ohms.
Prooptiki,
one trick you can try is add a couple of smaller caps in parallel with pos and neg rail of your cap bank, like 2.2uf or 1uF to improve the treble response. better to use metal poly or metal film or foil.... - just something to think about, often large electrolytics dont perform well at the top end however it is simple to add a couple of smaller caps to sort it out. (at least in amps i have built and listened to/ measured)
hope this helps
-Dan
one trick you can try is add a couple of smaller caps in parallel with pos and neg rail of your cap bank, like 2.2uf or 1uF to improve the treble response. better to use metal poly or metal film or foil.... - just something to think about, often large electrolytics dont perform well at the top end however it is simple to add a couple of smaller caps to sort it out. (at least in amps i have built and listened to/ measured)
hope this helps
-Dan
A have some good 0.01uf hovland or its better to try 3.3uf cheap films tha I also have?
In addition in avclub forum (greek), they reported the same thing for the highs coming from a compression driver, and when they changed the psu from CRC to 47mF-> 4mH->47mF they found that the highs are back!!!
Anyone tried it?
In addition If I choose a 4mH inductor how many watts should handle, and which resistance ?
In addition in avclub forum (greek), they reported the same thing for the highs coming from a compression driver, and when they changed the psu from CRC to 47mF-> 4mH->47mF they found that the highs are back!!!
Anyone tried it?
In addition If I choose a 4mH inductor how many watts should handle, and which resistance ?
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I cant see any problem using both in parallel with each power supply rail.
CLC is a good option too especially if you have high quality (low DCR high L wide bandwith inductors) i heard an amp recently with this and the noise floor was low despite having high gain. and moderate capacitance.
I would choose DCR as low as possible. (or as low as you can afford) preferably less than an 0.5 Ohm the power rating will be proportional to how low the DCR and Xl is.
I wonder if the compression driver used represented a more capacitive load ? or inductive load at its operating point.... too many unknowns for me to comment on this one really
Just thinking out loud here - actually listening to my F5 at the moment -
the supply i used was:
625VA toroid > 2 x 50A bridges > 2 x 30,000uF ELNA > LM338K x 2 > 2 x 27,000uF BHC Aerovox > 2 x .47uF poly caps
nothing special but the earths all return to one point literally.
i have to put my ear on the tweeter to hear the tiniest hiss and it measured about 1.8mV P-P ripple loaded with both channels.
PS: Nelson your amp design sounds great on Elsinore speakers.
-Dan
CLC is a good option too especially if you have high quality (low DCR high L wide bandwith inductors) i heard an amp recently with this and the noise floor was low despite having high gain. and moderate capacitance.
I would choose DCR as low as possible. (or as low as you can afford) preferably less than an 0.5 Ohm the power rating will be proportional to how low the DCR and Xl is.
I wonder if the compression driver used represented a more capacitive load ? or inductive load at its operating point.... too many unknowns for me to comment on this one really
Just thinking out loud here - actually listening to my F5 at the moment -
the supply i used was:
625VA toroid > 2 x 50A bridges > 2 x 30,000uF ELNA > LM338K x 2 > 2 x 27,000uF BHC Aerovox > 2 x .47uF poly caps
nothing special but the earths all return to one point literally.
i have to put my ear on the tweeter to hear the tiniest hiss and it measured about 1.8mV P-P ripple loaded with both channels.
PS: Nelson your amp design sounds great on Elsinore speakers.
-Dan
If the buzz is there with 2 RCA inputs and goes away when
you have one, then it's a ground loop. There are numerous
fixes involving moving and rotating transformers, improving
wiring layout and shielding.
One thing you can do is take the input ground of the RCA on
one channel only and connect it through 10 ohms.
I used the resistor, now if the rca are to the air all are silent! (before I had a very small buzz).
But when I connect them to my preamplifier a new kind o buzz!!! Its bigger than before and again in all the way of volume control but only to the one channel, the one with the 10ohm resistor!
Any ideas? (except that I have to make a star ground)
MEGA-amp, being from Conn. that's probably O.K. The humidity in this area really puts the ESD problem down. However, MOSFETs are extremely sensitive to static and living in Az. for the past 30 years, where the relative humidity rarely even gets to 20%, the situation would be the total opposite. I always install the Semi's last and I wear a gnd'ed wrist strap 
I have blown up commercial equipment that was poorly or not protected just by touching the volume control...
I have blown up commercial equipment that was poorly or not protected just by touching the volume control...
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MEGA-amp, being from Conn. that's probably O.K. The humidity in this area really puts the ESD problem down. However, MOSFETs are extremely sensitive to static and living in Az. for the past 30 years, where the relative humidity rarely even gets to 20%, the situation would be the total opposite. I always install the Semi's last and I wear a gnd'ed wrist strap
I have blown up commercial equipment that was poorly or not protected just by touching the volume control...
Thanks for the advice, I'll be getting a pad and wrist strap, quite affordable.
I think I'll move my build upstairs, its hardwood up there but carpet in this basement. Its cold as hell out, and the air is quite dry. With forced air gas heat, static may be high here!
Thanks again,
Russellc