Is this motor-boating?

[Nuuk]

I have just built some new speakers to go with my Gainclones. They use a full-range driver with no crossover.

After one and a half tracks, it sounded as though a sport cars was being driven out of the right hand speaker (my GC's are monoblocs).

Is this motor-boating? Or what else may be causing it? Is the lack of resistance by not using a crossover the problem but if so why only one channel?

 

[Duo]

It seems your problem is with a reactive load or something similar. It's weird that it only motorboats in one channel.

I have made a few amps before and found them to motorboat easily on certain speakers and be fine on others.

Are you sure everything is exactly the same for both channels? Speaker leads, speakers, amps, parts?

I would look into some filtering like a zobel network, maybe, some more negative feedback.... Less reactive speaker setup.

I can't shed a great deal of light on the situation, but there are many experienced people on this forum that can.

Just wait and I'm sure you'll get some good answers.

 

[JOE DIRT®]

try a .5 ohm 5 watt resistor on each speaker and get back to us

 

[Nuuk]

Hi guys, thanks for the replies.

I was using a single PSU before and have gone back to one PSU per channel and it's OK! I remember KYW saying something along the lines of using separate supplies with the inverted design but it worked OK with my other speakers.

 

[zeno]

Hi guys, thanks for the replies.

I was using a single PSU before and have gone back to one PSU per channel and it's OK! I remember KYW saying something along the lines of using separate supplies with the inverted design but it worked OK with my other speakers.

What speakers did you build?

I am experimenting a bit with Jordan JX92S full range chassis.

Just curious which full range chassis you are using in your new speakers!

Marc

 

[Nuuk]

What speakers did you build?

Hi Marc,

I'm not using anything special, just a 10UKP type that you can see HERE

I'm just playing around with a concept of a chassis to hold the driver and a 'skin' of polystyrene to make a three sided open baffle. It's strange having a speaker over a metre high that you can lift off the ground with one hand!

I'll be doing a full write up on my web site as soon as time allows.