Hello,
I have 2 subs and both are not working, one is a def tech pf15tl+ and the other is a jbl venue 12, both have amp issues, have recapped the jbl with no luck and also replaced the filter caps on the def tech also no luck. Tired of plate amps, thinking of just buying a external amp to get at least one of these working, not sure what I need to do this and how to hook up to what is there already. I have been reading and researching alot but am new to this and would really appreciate some advice. Thanks
I have 2 subs and both are not working, one is a def tech pf15tl+ and the other is a jbl venue 12, both have amp issues, have recapped the jbl with no luck and also replaced the filter caps on the def tech also no luck. Tired of plate amps, thinking of just buying a external amp to get at least one of these working, not sure what I need to do this and how to hook up to what is there already. I have been reading and researching alot but am new to this and would really appreciate some advice. Thanks
Some thoughts:
- Yes, it's theoretically possible to just remove the plate amp and use an external amplifier. I'd recommend SpeakOn connectors.
- I'd be hesitant to recommend this path, though, depending on which plate amps are being replaced. If you look at something like a JBL SRX active speaker, for example, the plate amps contain lots of DSP which has settings for EQ and limiting for those drivers in that cabinet. While it's possible to recreate that DSP yourself, the best bet is simply to either use the active speakers, or use the JBL presets (for, say, the Crown iTech range).
I'm not familiar with either of your subwoofers, so can't say how much processing they might or might not have.
In any case, a solid budget option would be a Behringer NX3000D, or the 6000D if you need more power. Those models have some DSP, in the form of EQ and peak limiters. If you need something more comprehensive, I really like the Powersoft T-series amps, which include FIR processing, as well as real-time power output monitoring/limiting. Others are available.
Chris
- Yes, it's theoretically possible to just remove the plate amp and use an external amplifier. I'd recommend SpeakOn connectors.
- I'd be hesitant to recommend this path, though, depending on which plate amps are being replaced. If you look at something like a JBL SRX active speaker, for example, the plate amps contain lots of DSP which has settings for EQ and limiting for those drivers in that cabinet. While it's possible to recreate that DSP yourself, the best bet is simply to either use the active speakers, or use the JBL presets (for, say, the Crown iTech range).
I'm not familiar with either of your subwoofers, so can't say how much processing they might or might not have.
In any case, a solid budget option would be a Behringer NX3000D, or the 6000D if you need more power. Those models have some DSP, in the form of EQ and peak limiters. If you need something more comprehensive, I really like the Powersoft T-series amps, which include FIR processing, as well as real-time power output monitoring/limiting. Others are available.
Chris
thanks
Thanks for the information, could I ask about the driver in my def tech is a 76 ohm speaker and the rms is 500 watts will that affect the amp I need to buy? Thanks for the help.
Thanks for the information, could I ask about the driver in my def tech is a 76 ohm speaker and the rms is 500 watts will that affect the amp I need to buy? Thanks for the help.
FWIW I am starting to see a trend, first here in Argentina but certainly valid in other Countries of course: I make musical instrument amplifiers and am regularly invited by customers to their live shows.
We are not talking Stadium level stars but average working "weekend" Musicians.
Was intrigued by PA guys showing up with "assorted brands" cabinets, say a coupleJBL, a couple EV, RCF, and so on.
Being the nerdy type, I always go backstage to check what´s being used and lo and behold, find originally powered speakers now sporting a nice plywood rectangle with a couple speakons mounted where the old plate amp used to be, sometimes the original plate is left, finned heatsinks included, simply to "cover the hole" but they are obviously gutted (all pots, switches, IEC and Audio connectors removed) and a couple speakons mounted instead.
They are typically driven with "leftover" rack amps (think indestructible Peavey CS800 and such) or even cheap chinese "DJ" type ones (think Numark, Pyramid, etc.).
As long as signal is split and limited by a cheap but decent crossover (think Behringer and such) results are quite acceptable.
Stellar/sophisticated sound? ... hardly.
"Save the day" usable sound? ... you bet.
I have been surprised by the very acceptable results offered by many of such "recycled" combinations.
We are not talking Stadium level stars but average working "weekend" Musicians.
Was intrigued by PA guys showing up with "assorted brands" cabinets, say a coupleJBL, a couple EV, RCF, and so on.
Being the nerdy type, I always go backstage to check what´s being used and lo and behold, find originally powered speakers now sporting a nice plywood rectangle with a couple speakons mounted where the old plate amp used to be, sometimes the original plate is left, finned heatsinks included, simply to "cover the hole" but they are obviously gutted (all pots, switches, IEC and Audio connectors removed) and a couple speakons mounted instead.
They are typically driven with "leftover" rack amps (think indestructible Peavey CS800 and such) or even cheap chinese "DJ" type ones (think Numark, Pyramid, etc.).
As long as signal is split and limited by a cheap but decent crossover (think Behringer and such) results are quite acceptable.
Stellar/sophisticated sound? ... hardly.
"Save the day" usable sound? ... you bet.
I have been surprised by the very acceptable results offered by many of such "recycled" combinations.
This supports my opinion that there are no significant sound differences between power amps besides their wattage.
This subwoofer is really a 76 ohm woofer, does that mean the amp would have to be extremely powerful to deliver the needed wattage? I thought most speakers were around 4 to 8 ohm, kind of new to the repair side of hifi and would like to get one of these subs working. Thanks for the info and advice on replacement.
Not more “powerful” - power is power regardless of the load. Getting that much power into such a high impedance speaker requires unusually high voltages. I think somewhere around 200v peak? I’ve never heard of such a thing. Are you 100% sure of that impedance and are you sure it’s not damaged? Do you have any pictures of the broken plate amp that you are trying to bypass?
Weird and can only imagine voice coil is damaged, big time.
How do you know it´s 75 ohm?
Did you actually measure that or it´s printed somewhere?
It might be a typo by a non-Roman alphabet user.
Or simply somebody dropped a decimal point and it´s actually 7.5 ohm speaker, which is WAY more reasonable.
How do you know it´s 75 ohm?
Did you actually measure that or it´s printed somewhere?
It might be a typo by a non-Roman alphabet user.
Or simply somebody dropped a decimal point and it´s actually 7.5 ohm speaker, which is WAY more reasonable.
Thanks
Thanks for the replies, the woofer is a 76 ohm woofer, I found it in the manual and also used my dmm and got 70.2 ohms, not sure what to do to make this useable with that impedance, any ideas? Hate to toss it. Thanks again.
Thanks for the replies, the woofer is a 76 ohm woofer, I found it in the manual and also used my dmm and got 70.2 ohms, not sure what to do to make this useable with that impedance, any ideas? Hate to toss it. Thanks again.
Have a read through this thread, if you haven't already. You'll find the schematics in there, for the 'plus' version (which claims peak output725W at 36Ω) and the 'non plus' version (with the STK4050V chip).
STK4050V and it's use in Definitive Tech PF15TL subwoofer
STK4050V and it's use in Definitive Tech PF15TL subwoofer
Thanks for the replies, I read thru the post and am starting to test the amp caps and resistors, have not located the resistor 89 that is discused in the thread. Will keep looking, appreciate the help.
