fender 400pro hissing / bypass head with pf500?

[stevemac]

I'm getting a lot of hissing in my existing fender 400 pro combo amp. I am going to take it in to the shop and see about getting it serviced but... I have been considering bypassing the head with a new pf350 or pf500 and seeing what that does for me since I'd like to start investing in ampeg gear (love the tone), and this seems a great way to ease in. Also would this fix my problem or is it too uncertain? I tried different cables and basses etc so its nothing external to the amp I can think of.

Also, since the fender 400pro combo is 350W at 4ohm and 500W at 2ohm I'm thinking the pf350 is the best fit, but would it kill my speakers to hook up a pf500? Where do the speaker watt ratings come from? I'd prefer to upgrade to the pf500 is why I ask. I assume the pf350/500 head comes with a 1/4" jack output so I can plug it into cab direct. I'm a bit of noob when it comes to amps, always used combos.

thank you bass gurus for any advice you can give to a grasshopper.

[BassmanPaul]

Your post is making no sense that I can understand. If you are talking about capacitor values they a written 500pF. Bypassing the head??

[stevemac]

Lol, no I'm not talking picofarads. I am refering to ampeg pf350/500 amp head (see link) to bypass the amp head on my combo.

Ampeg: Portaflex Series - PF-350

I'm not sure if you are making fun but hopefully this clears things up...

[BassmanPaul]

Originally Posted by stevemac

I'm not sure if you are making fun but hopefully this clears things up...

No fun intended!

I did clue in from another thread about these amps. PF: PortaFlex. Sorry.

My only comment would be that a combos speaker system is a bunch of compromises between engineering and marketing. Typically the box will be too small for what's mounted in it. You'd be better off in just selling the thing and buying a cabinet you actually like.

[JimmyM]

if you're going to get a pf500, i wouldn't even bother with the fender combo. i'd just get another cab. easy for me to say, right? but ultimately it's the way to go.

however, hissing usually means you are using a lot of treble with the tweeter turned way up. would this be the case?

[stevemac]

It only hisses when I hold a note, it practically dissolves it in my ears but not many people seem to even notice it except other bass players who ask what kind of distortion i am using.

The amp is at our drummers house will pick it up later this week and try some things but Im sure Ive tried lowering the treble and gain and any improvement was minimal.

Only reason I would get a pf500 now and use my old fender combo cab is financial, got a lot on the go with new house and renos etc that I can only justify a few hundred here and there for my band stuff so was thinking about buying in slow. And I am not sure yet which cab to get but I want something around what I have ~400w, love heavy ampeg sound so it seems the best bet to go with. Will pf500 be ok with this cab?

Dont worry I will take it in for service before doing anything but want to get some thinking going first.

[JimmyM]

ya, the pf500 will be fine as long as you keep the volume down to where the cab can handle it. but the problem with your fender combo doesn't sound major. one thing you might try is cleaning the effects loop jacks. sometimes they get corroded if you don't use them and they can cause problems. failing that, a shop trip is in order.

[stevemac]

Figured out what was wrong with my amp, blown speaker lol! I opened it up and disconnected one at a time and one is just sizzles instead of making nice bassy sounds. Would have thought it would be more obvious to me, oh well, will know next time.

Is it ok to disconnect and run one speaker (2x10) for a while or will it blow the other one seeing as its only one to the circuit instead of dividing load or is that how it even works? Just curious because the tech at the store I use isnt in until monday... it would be nice to do some jamming over the weekend ...well pretty much have to for gig, band wants to practice.