Definitive Technology BP2000 Amp Died - Replacement Options?

S

snakeeyes

Audioholic Ninja
These Def Tech speakers are on Craigslist all the time. Maybe find a used pair of newer series or even go used BP10 model which doesn’t use amps.

Otherwise there’s plenty of speakers that outperform the Def Techs if you are ready to move on.
 
J

Jwheel

Audioholic
Take the speaker that works and place a dummy plug in the LFE input. Now just connect a signal to the low input only and see if any sound comes from the sub as well as the low driver. If it does your plan will not work. If no sound comes from the sub driver under that test, then your plan will work.
TLS Guy, Thanks for the response. I'm not sure what you're referring to by a 'dummy plug'. Can you help me here? Thanks!
 
TLS Guy

TLS Guy

Seriously, I have no life.
TLS Guy, Thanks for the response. I'm not sure what you're referring to by a 'dummy plug'. Can you help me here? Thanks!
I mean just an RCA plug with nothing connected to it, as there is likely a detector to know if there is anything in that input.
 
J

Jwheel

Audioholic
So given the current situation, I started looking at some new speakers as suggested without internal amplifiers. Today on my local classifieds, I found a pair of mint condition AV123 RS750 Signature edition speakers in rosewood finish for $300. I'm aware of the epic demise of this company, but heard the speakers are good. Thoughts on these as replacements for the price?
 
Soundman

Soundman

Audioholic Field Marshall
So given the current situation, I started looking at some new speakers as suggested without internal amplifiers. Today on my local classifieds, I found a pair of mint condition AV123 RS750 Signature edition speakers in rosewood finish for $300. I'm aware of the epic demise of this company, but heard the speakers are good. Thoughts on these as replacements for the price?
Did you end up getting those speakers?
 
C

chriscolt

Audiophyte
In my experience (I repair vintage & new Vacuum tube and Solid State amps - instrument and Hi-Fi - for last 22 years) any amp can be repaired - the problem being cost of repair vs what the amp is worth - I own Definitive Technology speakers (love them BTW) 2 x BP200TL, 1 x 3000 CLR, 2 x BP 2004 & 2 x BPX - 7 channels total - 5 of which have built in subwoofers (3 front and side surrounds) - I had a few drivers go bad, 1 subwoofer and an AMP board for sub that was DOA when purchased new. Most times with any amp that is approaching 10 years or older - the power supply filter capacitors (Electrolytics) dry out and either open or short. If they open they ususally don't take any other components with them - with the right test equipment (I highly recommend the DER DE5000 LCR meter) - you can tell which are bad either by carefully looking at them (electrolytics sometimes swell up and pop on the tops or bottoms and leak a thick gooey liquid all over the circuit board - or you can use above mentioned LCR meter and test most of them in circuit using either the capacitance setting (look at cap rating printed on the barrel of cap e.g. - 1000uf is a typical filter cap value - and measure the cap with POWER OFF UNPLUGGED for at least 30 minutes - from wall outlet and disconnect speaker wire feeds short all the terminals and the electrical plug to discharge any caps that may be holding a charge to protect meter. Set meter for 120hz frequency and read cap - if it is off by more than 20% rated value it is suspect - more than 30% (1000uf cap measuring 1500 or higher or 500 uf or lower is bad - removing one side from the board and testing again will give a more precise reading just unsolder one leg - if more than 20% higher or lower then replace - but you are looking for a cap that is way off - that's the culprit) it should be changed. U can also test ESR set frequency to 100Khz for ESR testing - should read 0.1 - 0.3 ohms - any higher cap is suspect. If reading much higher like 20 - 100 ohms cap is bad.

All this assumes u have worked on electronics and know how to use a soldering iron correctly because if not u could do more damage. These parts cost pennies as compared to buying a new board or speaker - a 1000uf cap at 300V (buy name brands either American, German or Japanese - Sprague, F&T or Nichicon or Panasonic from MOUSER Electronics, Digikey or Newark). Always buy at least rated voltage or higher if it fits - so a 1000uf @ 250V can be replaced with same capacitance at 300, 350, 500 V so long as not too big NEVER buy a cap rated at less voltage than what is called for in circuit. I usually go 25-75% higher voltage rating because the caps will run cooler and last longer and cost difference is pennies. Caps cost between under $1.00 to $5.00 each depending on size and voltage rating - Tube amp caps are more $$$ cause tube amps voltages are much higher 400-800V than solid state which are usually well under 300V (15 - 200V typical). Sometimes a bad cap, diode or resistor (inexpensive passive parts) can cause a more expensive part (transistor, FET, JFET, OPAMP, etc..) to burn out - this is a more complicated fix and those parts depending on age and manufacturer may be harder to come by.

The other option is to search Ebay - I see these speakers being sold for next to nothing - cheaper than the parts - or people parting out working DEFTECH speakers - selling just the subwoofer amp board or selling a single or pair of BP2000TLs for around $100 - then you have a whole speaker's worth of parts - or if cabinet is in better shape - substitute their speaker for yours and keep yours for parts. I am surprised Def Tech won't sell you a subwoofer board - or fix yours (by removing board and sending it to them for repair). I bought drivers from them a couple of years ago for my speakers - a couple of tweeters, one mid/bass and one 15" subwoofer.

Finally - a dumb question - did you make sure it was the sub-woofer amplifier and not the speaker that was bad? When my speaker went I couldn't easily tell which was faulty because the amp will not power up without a speaker load connected to it -- I wound up using some clip leads connecting my other subwoofer to the amp in the faulty tower to make sure the problem followed the speaker - not the amp. A quick but not 100% sure way is to totally disconnect the subwoofer and use an ohmmeter across speaker terminals - u should read around 3 ohms for a 4 ohm speaker and about 6-7 ohms for an 8 ohm speaker - if you read OPEN (infinity) then the speaker voice coil is shot not the amp. To test amp for certain - swap the know good subwoofer for the one that u think the amp is bad and see if the problem persists - the amp turns on ONLY when it receives bass frequencies & a working subwoofer is attached to the output (load) otherwise it remains off. Again - I thought I had a bad sub amp board when in fact it was a bad subwoofer speaker with open voice coil.

If you want to post some pics of the assumed bad circuit board - front and back I can take a look to see if there is anything obvious - 908 400 2760 is my cell
 
R

reallintboy

Audiophyte
FYI, Definitive Technology still offers a legacy amp repair service. I just contacted them for a repair quote on my BP2000 amp as well as the amp in PF15TL.

"The prepaid flat rate for amp repairs is USD 300 per speaker. The fee covers shipping the amps only both ways. Provided you test the woofer, Definitive Technology Legacy amplifier repairs come with a 12-month warranty. If you do not test the woofer the repair does not carry a warranty."

They give instructions on how to test the woofer as well as remove the amp from the speaker enclosure.
 
F

fmw

Audioholic Ninja
I support your idea. Get a couple of plate amps and go for it.
 
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