Simplexx 1x12 questions

[Grant Bunter]

Many of Bill's designs are quite revealing!

While it may be unlikely the hiss is being caused by the cab itself, you should check all wiring and connections inside the cab to see if anything is loose or not that good a connection.

It is way more likely that the hiss is being caused by either the amp itself, the amps settings, or something upstream, and to work out what the cause may be, you need to walk through your entire chain.

Is it just bass directly into amp connected to cab?
If yes, check out your bass signal lead. Do you have a spare you can swap out to check?
Same for the bass itself, do you have a spare or a mate with a bass so you can plug that in, or see if it gets worse?
With the signal lead, if there is hiss with one, but not another, bin the bad one.
If you have hiss with your bass, but not your spare or the borrowed one, your bass has issues and needs a service.
If you can do that yourself, cool, if not, send it to a pro.

Is your amp's gain to high?
Turn the amp gain down and the master up and if the hiss goes, well, there's the answer.
Have you got the treble turned up? Or did you leave the settings the same as with your old cab (if you had one).
You might need to rebuild your sound from the ground up with a new cab.

If all these things check out ok, do you use effects pedals? If yes, remove one from the chain at a time, when the hiss goes, you found the faulty one.

All that's left if you've done all that, and you still have hiss, is that the amp is producing it. Get it serviced...

[Bill Fitzmaurice]

I am getting a fair amount of hiss from the tweeter, is this normal, or have I messed up somewhere?

Tweeters don't hiss. Electronics do.

[Verb]

Thanks for your replies.

I am getting hiss with just the amp connected to the cab, no bass connected. I still have hiss with the gain and master volume turned fully down. The hiss gets louder as I increase the master volume. I am getting the same results with both of my amps, a 90s Trace Elliot and a new Ashdown RM800, each has a new speaker cable.

As this is my first build I want to get it right. Is it possible the hiss is due to how I have assembled the crossovers?

[Grant Bunter]

Is it possible the hiss is due to how I have assembled the crossovers?

Not likely.
Show us some pictures though, in case you missed something.

Does dialing down the L Pad change the hiss?

[Verb]

I will pull the crossovers out and get some photos when I have time.

Yes, the L pad acts as a volume control for the hiss.

[Bill Fitzmaurice]

A mistake in the crossover wouldn't cause hiss. A cock up in the low pass might attenuate the woofer, making the tweeter more prominent. Tweeters, all drivers for that matter, don't create sound, they can only reproduce what's sent to them. Chances are you won't run the tweeter at more than 1/4 level anyway.