Hello all, so I have a question reguarding the build quality of these amps.
I have one at an install/refurb I'm working on that the owners want to reassign to dj monitors because it's cooked 3 pairs of speakers in the house (this is a large club).
Now I firmly belive it was just driven far too hard to the point where most of the
output signal was DC. Almost any amp will do this at a point so I can't blame the amp.
So my question is: is this amp capable of being driven hard every night in such an assignment as monitors for a dj?
Is the fact it cooked the speakers before itself a testament to the amp?
(Those who have ever mearly walked near a dj will know what they expect out of thier monitors.)
Thanks!
I have one at an install/refurb I'm working on that the owners want to reassign to dj monitors because it's cooked 3 pairs of speakers in the house (this is a large club).
Now I firmly belive it was just driven far too hard to the point where most of the
output signal was DC. Almost any amp will do this at a point so I can't blame the amp.
So my question is: is this amp capable of being driven hard every night in such an assignment as monitors for a dj?
Is the fact it cooked the speakers before itself a testament to the amp?
(Those who have ever mearly walked near a dj will know what they expect out of thier monitors.)
Thanks!
Assuming you're being serious, I know it's a home amp.
Again, I didn't put this system in. I've just been fixing the installers blatent disreguard for the laws of physics over the past 6 months.
Again, I didn't put this system in. I've just been fixing the installers blatent disreguard for the laws of physics over the past 6 months.
..but in case you were asking about it's job at the club, it was driving a pair of Bose 302A's. (Which I'm replacing with EV Sx80's)
Hi imix500,
Haflers were well built, although I haven't seen one of these before. Trust your instincts and use it for monitors. 2 ~ 2.5 A fast blow fuse in series might save the monitor if they oerdrive it again and it goes DC.
I would have a good look at it. Possibly it was improperly repaired in the past, not that would ever happen in a night club. 😉
-Chris
Haflers were well built, although I haven't seen one of these before. Trust your instincts and use it for monitors. 2 ~ 2.5 A fast blow fuse in series might save the monitor if they oerdrive it again and it goes DC.
I would have a good look at it. Possibly it was improperly repaired in the past, not that would ever happen in a night club. 😉
-Chris
Do you think they would give me an unbiased answer? Personally I think the thing would just overheat and shutdown, but I could add a couple fans to help.
Hi imix500,
Yes, I do think you would get an honest answer from Hafler. I hope anyway.
What monitors are you using or thinking of? Do they conform to a "home enviroment" speaker in terms of impedance? If so, you should be okay with the Hafler. They do not have a reputation for breaking.
-Chris
Edit: If you use fans, make sure you also cool the power transformer or it will open.
Yes, I do think you would get an honest answer from Hafler. I hope anyway.
What monitors are you using or thinking of? Do they conform to a "home enviroment" speaker in terms of impedance? If so, you should be okay with the Hafler. They do not have a reputation for breaking.
-Chris
Edit: If you use fans, make sure you also cool the power transformer or it will open.
Hey Chris, see that's where I'm not so sure with an amp that seems to be built for high quality control room monitoring. I'm sure it would do great in that application.
I'd just hate to put it in and damage a perfectly good amp cause it most probably will get occasionally abused in it's planned occupation.
Second question: the amp currently seems to be fine but having 3 pairs of 6 ohm speakers cook to a ~.5 ohm load three times- should I be worried about damage that might not be presenting itself right away?
I'd just hate to put it in and damage a perfectly good amp cause it most probably will get occasionally abused in it's planned occupation.
Second question: the amp currently seems to be fine but having 3 pairs of 6 ohm speakers cook to a ~.5 ohm load three times- should I be worried about damage that might not be presenting itself right away?
I've got a pair of eaw UB82's that would do the job no question, but because of space constraints I might have to go with some Control 28's or the like. They have the benefit of being cheap to fix.
run it up on a dummy load and check the clipping behavior. see if it has clipping "overhang". you might also want to check the operation of the protection circuits. did they wire those speakers in parallel?.......
interesting, overload protection shuts off the current source for the input diff amp. try driving a low resistance dummy load (1 or 2 ohms) and see what happens at the output when Q1 shuts off the diff amp.
the amp is only rated at 75w/ch, which is pretty small for it's use as a monitor amp. a monitor system. is generally 1/2 the power of the main PA amp (for a 600w system driving the house speakers, the monitor amp should be 300w).
interesting, overload protection shuts off the current source for the input diff amp. try driving a low resistance dummy load (1 or 2 ohms) and see what happens at the output when Q1 shuts off the diff amp.
the amp is only rated at 75w/ch, which is pretty small for it's use as a monitor amp. a monitor system. is generally 1/2 the power of the main PA amp (for a 600w system driving the house speakers, the monitor amp should be 300w).
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Hi, I am probably going to throw it on the audio precision at work and give it a good, hard test before connecting it to new speakers.
The Bose were connected one to each channel.
I know it's a smallish power amp in the "pro" world. The owners are trying to save money.
I can tell you with a less than 1 ohm load, the "short" led comes on with little input signal.
The thing that I question is that both speakers failed at exactly the same time, exactly the same way- on seperate channels.
The Bose were connected one to each channel.
I know it's a smallish power amp in the "pro" world. The owners are trying to save money.
I can tell you with a less than 1 ohm load, the "short" led comes on with little input signal.
The thing that I question is that both speakers failed at exactly the same time, exactly the same way- on seperate channels.
Ahh clubs...
I'd be honest. Tell them the amp is wrong for the application, and in the long term will cost them more in repair/call out fees. If they still insist on using it, I'd be tempted to stick a first order PLLXO in the input cables rolling off below, say 80Hz. That will greatly reduce the load on the amp, for probably little perceptable difference for a DJ. 😉
Oh, another thought, what is the input level on the amp? If it's domestic, the desk may well be overloading the input stage when turned up.
I'd be honest. Tell them the amp is wrong for the application, and in the long term will cost them more in repair/call out fees. If they still insist on using it, I'd be tempted to stick a first order PLLXO in the input cables rolling off below, say 80Hz. That will greatly reduce the load on the amp, for probably little perceptable difference for a DJ. 😉
Oh, another thought, what is the input level on the amp? If it's domestic, the desk may well be overloading the input stage when turned up.
Hi Al,
Good thought.
Yes, roll off the bass. They will get "thud" from outside and this way it won't cancel. Power requirements are then greatly reduced and you won't bounce the cones on the monitors out of the gaps.
75 W in a DJ booth should be enough unless you get an idiot DJ, then all bets are off no matter how much power you have in there. Add an over easy compressor if you want to be safe.
Hi unclejed613,
-Chris
Good thought.
Yes, roll off the bass. They will get "thud" from outside and this way it won't cancel. Power requirements are then greatly reduced and you won't bounce the cones on the monitors out of the gaps.
75 W in a DJ booth should be enough unless you get an idiot DJ, then all bets are off no matter how much power you have in there. Add an over easy compressor if you want to be safe.
Hi unclejed613,
Someone likes to sell gear! What about a 3 KW or greater bank?? Honestly, most DJ booths may run a 250 W amp, but that's only because it's an older amp or they bought a whack of them.
-Chris
Pinkmouse, the system is fed by a Rane RPM88. It's set for +4 out.
Hey guys, so I think I've come up with a solution. They have an unused crest 6001 and I might be able to free up a couple channels on one of thier Ashly powerflex 6250's. (As long as they stop blowing up) So I could put the 6001 on the dj mons and buy a $150 dbx comp for some good old fashioned brickwall limiting. And then use the free channels on the Ashly for the new EV's. The hafler would then be eliminated.
If something doesn't seem right with the hafler when I get it burning some sine, I'll probably have more questions. Thanks!!
Hey guys, so I think I've come up with a solution. They have an unused crest 6001 and I might be able to free up a couple channels on one of thier Ashly powerflex 6250's. (As long as they stop blowing up) So I could put the 6001 on the dj mons and buy a $150 dbx comp for some good old fashioned brickwall limiting. And then use the free channels on the Ashly for the new EV's. The hafler would then be eliminated.
If something doesn't seem right with the hafler when I get it burning some sine, I'll probably have more questions. Thanks!!
Hi imix500,
I was thinking your Hafler was sick. Pick it up for scrap if you can and restore it.
-Chris
Perfect. 😉
I was thinking your Hafler was sick. Pick it up for scrap if you can and restore it.
-Chris
So I did get this amp for basically scrap (traded for an hour of my time).
Right off, it needs new pots. One has a mechanical failure- the wiper has broken off inside. The other is just too dirty to save. Also since it has a born on date of '97, it probably could use a cap job.
I called Rockford and they gave me a price of $3.70 a piece for the pots which isn't bad at all, but they have a $25 min.
So here is my dilemma, I can buy replacement caps from them and probably easily hit $25 or try to find pots that will work and get better caps (MKP's maybe?) and maybe bigger filter caps.
Btw, I did test the amp and it is still perfoming great. Anything else I should look at upgrading/replacing?
Right off, it needs new pots. One has a mechanical failure- the wiper has broken off inside. The other is just too dirty to save. Also since it has a born on date of '97, it probably could use a cap job.
I called Rockford and they gave me a price of $3.70 a piece for the pots which isn't bad at all, but they have a $25 min.
So here is my dilemma, I can buy replacement caps from them and probably easily hit $25 or try to find pots that will work and get better caps (MKP's maybe?) and maybe bigger filter caps.
Btw, I did test the amp and it is still perfoming great. Anything else I should look at upgrading/replacing?
Hi imix500,
Don't you hate it when they don't overcharge? 😀
Look at the prices for main filter caps from them or cosmetic parts as well. Normal caps are readily available so you may as well buy stuff you can't get anywhere else.
Good deal on your amp BTW. Congrats! 😉
-Chris
Don't you hate it when they don't overcharge? 😀
Look at the prices for main filter caps from them or cosmetic parts as well. Normal caps are readily available so you may as well buy stuff you can't get anywhere else.
Good deal on your amp BTW. Congrats! 😉
-Chris
Hey Chris, unfortunately they don't have any cosmetic parts left for this amp cause it could use a new faceplate. I think I'm going to do a total upgrade to the amp on the pots and signal/psu caps. The original pots were not exactly high quality so I'll probably find an alps or something that will fit on the little bracket they use to support it. Replace the stock poly signal caps with MKT and change all the small lytics to panasonics. There is real estate for larger 10k uf main filter caps so probably uni chemicons there. Any bad ideas in doing these mods?
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