I recently got hold of some 2nd hand Wharfedale Valdus 500s and wired them up to a Sony amplifier (80W RMS per channel into 8 ohms). To my suprise the amplifier cuts out whenever the bass in a song reaches a 'peak' level or if the amplifier is turned up past number 4.
I've tried this amplifier with some 100W mission speakers and everythings fine.
The Wharfedale speakers I'm using say '200W PROG 4 - 8 ohms' on the back if that helps.
I've checked the connections/cables for possible shorts but that part seems to be ok.
Has anyone got any ideas? Someone suggested that the crossovers in the speakers might need replacing?
Hi there .. had the same problem recently (see post 2 days ago). If the wires are ok, will be a problem with the speakers. To be sure, try putting the volume to the same level using headphones and no speaker output from the amp, Ideally test it with a new set of speakers.
The amp works fine with heaphones connected and speakers disconnected (or turned off using the speaker on/off switch).
I'm pretty sure its just the speakers that are causing this but not sure what I can do about it, ideally I would like to get them to work or at least undertand why they don't.
The amp is cutting out because you are asking too much of it. The load the Wharfedales present to the amplifier is not similar to the load of the Missions. "Wattage" recommendations of speakers are meaningless. You need to know the total impedance swing and electrical phase angle of the Wharfedales. The best guess is they are asking too much current to be passed from the Sony. Turn the volume down and the amplifier will rpobably be able to handle the speaker load.
Yes, changing the crossover would change the load the speaker shows the amplifier. However, if you don't know what the drivers themself require from the crossover (what crossover frequency, what filter slope, what correction networks, etc.) or what impedance the drivers show, changing the crossover is a crap shoot that could actually make matters worse, not better. If you change the crossovers, you will no longer have a Wharfedale speaker. You should assume the crossovers in the Wharfedales were put together by someone who knew what they were doing. Changing that could leave you with a mess. Buying new speakers might be the better solution. And, by the way, my guess is only that. I can't tell you this is exactly what is happening with the information you've provided. Knowing more about the speakers would help you determine whether your amplifier can ever be happy driving the Wharfedales at high volumes with lots of bass. In case you didn't know this, Sony receivers are not well known for handling difficult loads.
I don't know what frequency range/impedence the individual drivers (there's 3 on each speaker - they're floorstanders) or tweeters are, it doesn't even say on the back of the the drivers.
Maybe it would just be best to get some new speakers but if I did want to run the Wharfedales on another amplifer what rating would this need to be? The only info I have about them is what's on the back (see my 1st post).
Is there ay other way to get this info?
P.S Didn't know that Sony amps were known for not handling difficult loads well, I did try these on a Pionner amp (40W RMS x 2) and a Yamaha (100W RMS x 2) and had the same problems - they blew the anti-surge fuse in the Yamaha :-(
There are a few receivers that are built to handle difficult loads. HK and Outlaw do OK with hard to drive speakers. You need to look for an amplifier that has high current capability. If you move to separate amplifiers, the market is wider than when you stick to receivers. Most of the Japanese brands of receivers or separates don't do well at delivering current. One problem is neither speaker nor amplfiier manufacturers quote specs which are helpful in deciding which amp will drive which speakers. The best approach is to either trust a knowledgeable salesperson or call the manufacturer. Giving Wharfedale a call might confirm whether the speakers you own are considered a current hungry design.
In that case I think it's best to get rid and get some different ones, my intention was to use these speakers and a Sony amp to listen back to our band recordings from our Tascam 8 track so maybe some bookshelfs would be better anyway.
I had a Sony car amp and Sony 6 1/2" component speakers which the same thing happened, what was happening was the protection circuit in my crossover for the components would kick in and show the amp I was getting a short, I bypassed the protection in the crossover and all was well.Do the Warf's have a protection circuit built into the speaker?