Unlikely to be the chip protection circuits cutting in.
The chip is likely to be hot for that "cut-out" to happen.
Protection triggering on transients will not sound like a cut-out.
Similarly clipping is the rough tizzle on the peaks that gets worse the higher so take the input signal.
It sounds much more like a bad pot that is lifting off the track at the end of it's rotation.
But you should never be up at that end of the pot, unless you like listening to gross distortion.
Do you go to a lot of loud, low quality discos?
The chip is likely to be hot for that "cut-out" to happen.
Protection triggering on transients will not sound like a cut-out.
Similarly clipping is the rough tizzle on the peaks that gets worse the higher so take the input signal.
It sounds much more like a bad pot that is lifting off the track at the end of it's rotation.
But you should never be up at that end of the pot, unless you like listening to gross distortion.
Do you go to a lot of loud, low quality discos?
Chips are barely above ambient, after a few hours of continuous use the heatsinks now aren't cold to the touch, but about room temp.AndrewT said:
I remember what clipping is now, where it becomes square-wave at the peaks. Hence icky sounds.
It sounds much more like a bad pot that is lifting off the track at the end of it's rotation.[/QUOTE]
That's what I was thinking and hoping.
As I said earlier in the thread, I don't actually listen at these volumes, I just wanted to make sure I hadn't done anything cruel to my chips in having tested it at high volume. It's nowhere near as loud as previous amps have been though, it's not like it's painful to use at that volume, just pointless. Oh, and the answer to your question is that I despise clubbing and all forms of painfully loud and horrifyingly poor quality music.
--
Nathan
No...that's actually a good way to go...one tranny and one rectifier/PSU board to feed two amp boards cuts down on ground loops and other issues.
I like symetric layouts or layouts where the power section has as much separation as possible from the signal side...something like the tranny in the middle and the amps outboard...maybe have the heatsinks hang out the sides...I don't know...just thinking out loud...good luck!
I like symetric layouts or layouts where the power section has as much separation as possible from the signal side...something like the tranny in the middle and the amps outboard...maybe have the heatsinks hang out the sides...I don't know...just thinking out loud...good luck!
I woulda gone a little bigger with the tranny since this is an unregulated PSU design with little in the way of capacitance but yeah...should work OK.
For my little mono project I went with a nice little 90VA tranny made in England of all places...looked almost like NOS...that's how nice it was...
For my little mono project I went with a nice little 90VA tranny made in England of all places...looked almost like NOS...that's how nice it was...
Good & Bad News
Bad news... I am in the process of moving house, was transporting my amp yesterday, and it fell about a metre onto wet concrete.
Good news... I very carefully checked over everything, the only bits that were damaged were a couple wires from PSU to amp boards were slightly squished and the panasonic caps were scraped, the plastic top came off one.. very VERY tentatively tested it in the new flat, everything works fine! Hooray!
CarlosT, so far the amp has been plenty loud and bassy (is that even a word?) even with only a small trafo, and this is only from a PC which appears to give about 0.3V outputs. So it could go MUCH louder. Maybe I have relatively sensitive speakers?
I'm quite happy with the layout myself, I don't think I'd be able to tell the difference between different setups in terms of sound anyway. Plus I already had the way I wanted the amp to look set in my head before I started the project. It had to be 440mm wide, 228mm deep, due to the pieces I'm using for bottom corners, and it had to be as short (height) as possible. It also had to have a very minimalist front panel, preferably with only a volume dial, or nothing if I add a preamp and use it as a power amp.
I'm thinking about building a 4 ohm sub channel using the spare rectifier and a 120VA 2x22v transformer I have lying around.
Also going to be adding a preamp: Rod Elliott's (ESP) p37a.
More later, and pics to come!
--
Nathan
Bad news... I am in the process of moving house, was transporting my amp yesterday, and it fell about a metre onto wet concrete.
Good news... I very carefully checked over everything, the only bits that were damaged were a couple wires from PSU to amp boards were slightly squished and the panasonic caps were scraped, the plastic top came off one.. very VERY tentatively tested it in the new flat, everything works fine! Hooray!
CarlosT, so far the amp has been plenty loud and bassy (is that even a word?) even with only a small trafo, and this is only from a PC which appears to give about 0.3V outputs. So it could go MUCH louder. Maybe I have relatively sensitive speakers?
I'm quite happy with the layout myself, I don't think I'd be able to tell the difference between different setups in terms of sound anyway. Plus I already had the way I wanted the amp to look set in my head before I started the project. It had to be 440mm wide, 228mm deep, due to the pieces I'm using for bottom corners, and it had to be as short (height) as possible. It also had to have a very minimalist front panel, preferably with only a volume dial, or nothing if I add a preamp and use it as a power amp.
I'm thinking about building a 4 ohm sub channel using the spare rectifier and a 120VA 2x22v transformer I have lying around.
Also going to be adding a preamp: Rod Elliott's (ESP) p37a.
More later, and pics to come!
--
Nathan
Re: Good & Bad News
An average signal voltage of around 300mV could see slow speed transients that would register on a multimeter as peaks of upto 600mV. But the short term transients will not be displayed and could go as high as 20db above the average signal, i.e.3Vpk.
Your PC may already be using most of the available normal listening volume if you want to retain the usual 10 to 20db of overhead for transient signal in dynamic source material.
probably not.MunkeeVegetable said:
An average signal voltage of around 300mV could see slow speed transients that would register on a multimeter as peaks of upto 600mV. But the short term transients will not be displayed and could go as high as 20db above the average signal, i.e.3Vpk.
Your PC may already be using most of the available normal listening volume if you want to retain the usual 10 to 20db of overhead for transient signal in dynamic source material.
I have a dilemma, but of a different sort. I have a chipamp.com 3886 kit, soldering iron is hot, components in hand but I cannot reach the site for the manual!
I have the PS built, all I need are the values for some resistors - can anyone help me?
r1, r2, r3, rm, rf, rz
and do you solder r3 into the outside hole to utilize the feedback cap?
I have the PS built, all I need are the values for some resistors - can anyone help me?
r1, r2, r3, rm, rf, rz
and do you solder r3 into the outside hole to utilize the feedback cap?
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