zastin17
Active Member
I have had this wonderful old amplfiier for around 8 years. I got it completely factory, and somebody shorted out the lamp circuit. Easy fix luckily!!
Worked great after clearing the short. The entire time I've owned the amp, it has had this strange behavior when I set it to 4x channel bridge mode. I do have more power headroom on 75w and its obvious to me.
Sounds great.. until it doesnt. The issue is the amp will clip/chirp and make scary abrupt sounds when I bring volume to near max for a particular speaker. This only happens when the amp clips. But it clips very overally hard. Dangerous signal for speakers. Scary actually.
When in 4x channel mode. This doesn't happen. Sound quality is identical with slightly less power. But the thing is, I get slightly more volume headroom due to the clipping being much softer in 4x channel. So I can potentially bring the same pair of speakers to a higher volume on 25w due to soft clipping.
Where on 75w, until it barley clips is basically my max possible safe volume.
I have cleaned all switches, and it seems nothing I do to do the amp changes this behavior. I cleaned the 2x channel switch aswel. No problems there. I have resoldered pretty much every joint on this amp.
A year ago, I went capacitor crazy and recapped the entire unit top to bottom very thoughtfuly and slowly. I had perfect success and the amp never sounded better. However I thought this would fix the clipping. But it stayed precisely the same. It's as If it's a feature of my 4140. But I still feel it's an issue and not a feature, so I'm here asking why this is happening?
Last I adjusted bias for the Outputs it was was Bang on. No drifting like with the old leaking Elna caps. That's what set me off to replace all the caps in the first place. I then found leaking eletrlytic hidden under most capscitors I pulled. Haha. I'm just glad I could give this old thing much more potential life.
I mean I read some things about the 2270 and simular complaints.
But I feel since this amp doesn't do this in 2x channel, and that's a bit odd. Ad the 2270 is 2x channel.
If anybodies curious, the filter caps re CDM Cornell Dubilier USA 22,000uF @80. I got lucky at my local surplus Gizmos one day and found some really great new replacements. Caps were meant for PCB mounting. So I just had to twist the caps in a way so the ground bar had clearance.
Also I have to ask, what the heck are with the prices latley? Oh my!! I got this thing for $100 broke . Now the prices are in crazy land.
Worked great after clearing the short. The entire time I've owned the amp, it has had this strange behavior when I set it to 4x channel bridge mode. I do have more power headroom on 75w and its obvious to me.
Sounds great.. until it doesnt. The issue is the amp will clip/chirp and make scary abrupt sounds when I bring volume to near max for a particular speaker. This only happens when the amp clips. But it clips very overally hard. Dangerous signal for speakers. Scary actually.
When in 4x channel mode. This doesn't happen. Sound quality is identical with slightly less power. But the thing is, I get slightly more volume headroom due to the clipping being much softer in 4x channel. So I can potentially bring the same pair of speakers to a higher volume on 25w due to soft clipping.
Where on 75w, until it barley clips is basically my max possible safe volume.
I have cleaned all switches, and it seems nothing I do to do the amp changes this behavior. I cleaned the 2x channel switch aswel. No problems there. I have resoldered pretty much every joint on this amp.
A year ago, I went capacitor crazy and recapped the entire unit top to bottom very thoughtfuly and slowly. I had perfect success and the amp never sounded better. However I thought this would fix the clipping. But it stayed precisely the same. It's as If it's a feature of my 4140. But I still feel it's an issue and not a feature, so I'm here asking why this is happening?
Last I adjusted bias for the Outputs it was was Bang on. No drifting like with the old leaking Elna caps. That's what set me off to replace all the caps in the first place. I then found leaking eletrlytic hidden under most capscitors I pulled. Haha. I'm just glad I could give this old thing much more potential life.
I mean I read some things about the 2270 and simular complaints.
But I feel since this amp doesn't do this in 2x channel, and that's a bit odd. Ad the 2270 is 2x channel.
If anybodies curious, the filter caps re CDM Cornell Dubilier USA 22,000uF @80. I got lucky at my local surplus Gizmos one day and found some really great new replacements. Caps were meant for PCB mounting. So I just had to twist the caps in a way so the ground bar had clearance.
Also I have to ask, what the heck are with the prices latley? Oh my!! I got this thing for $100 broke . Now the prices are in crazy land.
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