What commercial amps (if any) come with decent components and build quality?
For example, if someone were looking for something with the performance of a decent NAD amp (let's call this "solid, but not really earth shattering") but without the stupid implementation failures (like putting electrolytics next to hot components, or hot components so close to the board that they turn the PCB into a crisp) and without the bucket of crap brand capacitors that give out and turn the whole thing into a doorstop after a few years... What might they be looking at?
For example, if someone were looking for something with the performance of a decent NAD amp (let's call this "solid, but not really earth shattering") but without the stupid implementation failures (like putting electrolytics next to hot components, or hot components so close to the board that they turn the PCB into a crisp) and without the bucket of crap brand capacitors that give out and turn the whole thing into a doorstop after a few years... What might they be looking at?
Crown comes instantly to mind.
A good range of reliable commercial amplifiers from 250W to 5kW output.
A good range of reliable commercial amplifiers from 250W to 5kW output.
Not so sure about that.
If design/layout/wiring are not good, plain swapping components won´t solve any of that.
Even worse if component swapping is governed by blindly trusting wild vendor´s claims.
If design/layout/wiring are not good, plain swapping components won´t solve any of that.
Even worse if component swapping is governed by blindly trusting wild vendor´s claims.
Just don’t expect that from the cheapest ones they offer. Same for ANY “pro” amps these days.
I've been happy with Peavey CS800s (.03% HD 400 w rms/ch 4 ohms, .02% hd 260 w/CH 8 ohms) and the CS600s sounded good at the local dealer. 100 db s/n 4 ohms. Slew rate 40 v/usec XLR & 1/4 phone mono input. Has clip protection (defeatable) and relay speaker detect for DC on speaker. I buy used ones and replace mains & supply caps since they are 25 years old. The first was stolen, I have the 2nd and am donating one.
The QSC CX302 I just bought for donation is rated .05% HD 325 w/ch 4 ohms .03% HD 200 w/ch 8 ohms. 106 db s/n. Clip protection (defeatable) Sound is fine. The fan is noisier at low watts than the Peavey. XLR & screw block input. There is "DC fault shutdown" but no speaker relay.
I leave clip protection on, it never lights up unless a input cable pops loose or a microphone is dropped or something. Neither of which event is good for your tweeter. I've blown 2 tweeters with dynaco ST70 that wasn't oscillating.
In the fan free department, I bought a Peavey M-2600. .1% HD 75 w/ch 8 ohm 130 w/ch 4 ohm s/n 95 db slew rate 15 v/usec. Has clip protection. As this uses a TL074 op amp I'm viewing replacing that with a 33079 with additional 33 pf caps around the feedback resistors. This should get HD & noise down some. 1/4 phone mono in & out, no DC speaker protection. PCB is dual layer so drilling for bypass cap installation should be non-dangerous. Did the electrolytic capacitor replacement already.
The QSC CX302 is to replace a QSC RMX850i at a church with a dead channel. Might have been sold that way, might have that channel turned off with the digital interface, don't know. Screwy digital controls with one pushbutton and no instructions on internet, I'm afraid to mess with it since it is 24 miles from my support base. The CX302 has volume pots, pretty DOH! human interface. Tried to use 2nd channel of RMX850i to power a remote 8 ohm speaker for covid patients (me) in another room with another entrance. Sound goes in RMX850i from mixer, doesn't come out speaker terminals. Had to skip church 9 weeks during & after delta variant.
The CS800s & CX302 were switcher supply. Big advantage of that, when you buy a used one it doesn't cost $90 UPS or Fed Ex. Transformer models like CS800x have the good specifications but weigh 75 lb, too heavy to ship USPS. UPS knows where to raise the price since there is no competition. I've repaired 3 early switcher supplies, not so sophisticated. A filter cap goes out & blows a fuse, NTCR used as a fuse, resistor used as a fuse. No scope required.
All these commercial amps sound better than my dynaco ST70 (1% HD on a good day) and ST120 (developed a -40 db hum I haven't found yet, has a closed loop idle bias control that blows the input transistor periodically & goes to 200 ma bias).
The QSC CX302 I just bought for donation is rated .05% HD 325 w/ch 4 ohms .03% HD 200 w/ch 8 ohms. 106 db s/n. Clip protection (defeatable) Sound is fine. The fan is noisier at low watts than the Peavey. XLR & screw block input. There is "DC fault shutdown" but no speaker relay.
I leave clip protection on, it never lights up unless a input cable pops loose or a microphone is dropped or something. Neither of which event is good for your tweeter. I've blown 2 tweeters with dynaco ST70 that wasn't oscillating.
In the fan free department, I bought a Peavey M-2600. .1% HD 75 w/ch 8 ohm 130 w/ch 4 ohm s/n 95 db slew rate 15 v/usec. Has clip protection. As this uses a TL074 op amp I'm viewing replacing that with a 33079 with additional 33 pf caps around the feedback resistors. This should get HD & noise down some. 1/4 phone mono in & out, no DC speaker protection. PCB is dual layer so drilling for bypass cap installation should be non-dangerous. Did the electrolytic capacitor replacement already.
The QSC CX302 is to replace a QSC RMX850i at a church with a dead channel. Might have been sold that way, might have that channel turned off with the digital interface, don't know. Screwy digital controls with one pushbutton and no instructions on internet, I'm afraid to mess with it since it is 24 miles from my support base. The CX302 has volume pots, pretty DOH! human interface. Tried to use 2nd channel of RMX850i to power a remote 8 ohm speaker for covid patients (me) in another room with another entrance. Sound goes in RMX850i from mixer, doesn't come out speaker terminals. Had to skip church 9 weeks during & after delta variant.
The CS800s & CX302 were switcher supply. Big advantage of that, when you buy a used one it doesn't cost $90 UPS or Fed Ex. Transformer models like CS800x have the good specifications but weigh 75 lb, too heavy to ship USPS. UPS knows where to raise the price since there is no competition. I've repaired 3 early switcher supplies, not so sophisticated. A filter cap goes out & blows a fuse, NTCR used as a fuse, resistor used as a fuse. No scope required.
All these commercial amps sound better than my dynaco ST70 (1% HD on a good day) and ST120 (developed a -40 db hum I haven't found yet, has a closed loop idle bias control that blows the input transistor periodically & goes to 200 ma bias).
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