WOPL running 4 Ohm speakers

[mr_rye89]

Bose 901s soak up a lot of power due to the steep eq curve. Consider another 400 or a 700

 

[plex]

did you try a different preamp? Your pre may be doing it.

Trying out another preamp will let you know.

 

[WOPL Sniffer]

Yep, the sensitivity on 901's is probably in the 80's which is terribly inefficient. Try a different set of speakers.

 

[WOPL Sniffer]

Trying out another preamp will let you know.

And get a fan on the amp

 

[WOPL Sniffer]

Next, try another set of speakers

 

[WOPL Sniffer]

How do you have the EQ hooked up (for the 901's)?

 

[Gibsonian]

Something rotten in Denmark. I run 4 ohms daily on an 8 fin 400, push the speakers to bottoming out on the cone backswing, that's my signal to turn it down. Only grab a fan if the cranking is long term stupid. Pic below of what I am bottoming out. Zero audible distortion from barely heard to all the speakers can take. Since you change speaks and it goes away it is either the amp or the speakers imo. I get mine plenty hot, never a hint of distortion.

 

[FredR]

Could be a safe operating area (SOA) issue. Exact issue I encountered. On all my WOPLs I've disabled that protection so I can drive 2 ohm speakers. No problem since. Most don't recommend that balls to the wall approach. Fuse protection is still there. Ask Joe about it.

Fan required.

 

[plex]

Next, try another set of speakers

Speakers sound good running 8 ohm

 

[Gibsonian]

Speakers sound good running 8 ohm

But it could be the specific 4 ohm speakers you are using. Try another pair of 4 ohm speakers and if still distorts, it's the amp.

 

[WOPL Sniffer]

Are you using the EQ with the 901's??? Do those models use one???

 

[plex]

How do you have the EQ hooked up (for the 901's)?

both through tape monitor and connecting between pre amp and amp same result.

 

[Gibsonian]

You still haven't ruled out your 4 ohm speakers as the source of the issue yet.

 

[Vynuladikt]

I ran 4 ohm for quite a while on my 400WOPL, only had distortion if I ran it hard enough to heat it up pretty hot. 8 fin no fan, took about 8-10 minutes of hard cranking and then it would start to lose clarity.

 

[FredR]

History from 2018 thread.

https://forums.phxaudiotape.com/threads/all-4-rail-fuses-go-nucular.8317/

 

[WOPL Sniffer]

Are you using 2 901's or 4? You said you hooked them up in parallel

 

[plex]

I thought you said it was distorting right away

2 speakers running 8 ohm no problem. 4 speakers running 4 ohm clipping as soon as volume get loud.

 

[WOPL Sniffer]

I hope you are not trying to run 2 speakers per side in parallel

 

[WOPL Sniffer]

2 speakers running 8 ohm no problem. 4 speakers running 4 ohm clipping as soon as volume get loud.

Get them extra speakers off there. The book will tell you the same. You can't do that. It's WAY less than 4 ohms in parallel.

 

[WOPL Sniffer]

You got the wrong amp for that shit