My 1st half stack, how to hook it up?

[ozzynotwood]

I tried heaps of amps and speakers over the past few weeks and I have settled on the Randall G3 RH300 with a Marshall 1960A quad. (which i havent ordered until I've read the responses from this post)

This will be my 1st half stack and I dont know how to connect it all up so nothing blows up in my face. I know I could ask the music shop how they hook it up, but I just dont trust those guys, they're just salesmen that arent interested in helping.

The head has 'parallell' outputs (2x 8ohm outputs I think). The only marshall specs i was able to get was "4 or 16 ohm mono, or 8 ohm stereo operation, handles 300w power".

So finally, the question, how do I hook up the head and cab so that I'm getting the most out of everything?

Due to lack of web updates and dialup internet now downloading pages, I wasnt able to get any more specs. Sorry!

---John

 

[Simon_F]

Re: My 1st half stack, how to hook it up?

That's a solid state amp, isn't it? The general rule with SS is that it's OK to connect a cab with a higher impedance than the amp, but the amp will deliver lower wattage than with a cab equal to the amp's stated impedance. You shouldn't connect a cab with an impedance lower than the amp's stated impedance.

I think that cab will be 16 ohms running in mono, so connecting it with one cable to an 8 ohm output on an SS amp won't cause a problem, but you won't get 300 watts of output. My guess is it will still be plenty loud!

 

[ozzynotwood]

Re: My 1st half stack, how to hook it up?

That's a solid state amp, isn't it? The general rule with SS is that it's OK to connect a cab with a higher impedance than the amp, but the amp will deliver lower wattage than with a cab equal to the amp's stated impedance. You shouldn't connect a cab with an impedance lower than the amp's stated impedance.

I think that cab will be 16 ohms running in mono, so connecting it with one cable to an 8 ohm output on an SS amp won't cause a problem, but you won't get 300 watts of output. My guess is it will still be plenty loud!

So shouldn't I just go from the heads 8ohm output to the cabs 8ohm input?

 

[Simon_F]

Re: My 1st half stack, how to hook it up?

So shouldn't I just go from the heads 8ohm output to the cabs 8ohm input?

I think you have to run the cab in stereo to get 8 ohm inputs, so if you only use one you'll only be using two speakers in the cab.

I'm not sure what the load on the amp would be if you ran the two parallel outputs into the two 8-ohm sides of the cab - so I deliberately didn't mention that, but I'm sure someone else will be able to advise you.

One thing to bear in mind is that you have a 300w amp and a 300w cab, so you probably don't want to run the amp at its maximum output potential. If you peak over 300w there is a risk of damaging the speakers. If you run a single 8 ohm output into the 16 ohm cab you won't be delivering the full 300w (which is probably a good thing), and as I said before I bet it will still be pretty loud.

 

[ozzynotwood]

Re: My 1st half stack, how to hook it up?

I think you have to run the cab in stereo to get 8 ohm inputs, so if you only use one you'll only be using two speakers in the cab.

I'm not sure what the load on the amp would be if you ran the two parallel outputs into the two 8-ohm sides of the cab - so I deliberately didn't mention that, but I'm sure someone else will be able to advise you.

One thing to bear in mind is that you have a 300w amp and a 300w cab, so you probably don't want to run the amp at its maximum output potential. If you peak over 300w there is a risk of damaging the speakers. If you run a single 8 ohm output into the 16 ohm cab you won't be delivering the full 300w (which is probably a good thing), and as I said before I bet it will still be pretty loud.

Thanks mate, you've been a great help, I appreciate it!

How much power would I be losing running into the 16ohm input of the marshall?

Can anybody educate me in what would happen if I connected the two 8ohm outputs to the two 8ohm inputs in the marshall?

 

[greendy123]

Re: My 1st half stack, how to hook it up?

When running cabs and heads try to run equal ohms between the cab and head. I think when running the 2 outputs to the 2 inputs of cab might not be a good idea. Easiest setup would be one output from the head to the input of cab is what you should do. If I were you I would just find a cab that takes a mono 8ohm input. I think many 2x12 cabs have that option, also you other 4x12's may have a 8ohm input depending the speakers the cab has.

 

[ozzynotwood]

Re: My 1st half stack, how to hook it up?

Useful info, thanks man So how much power am I going to lose when running from 8ohms into the 16ohm input?

 

[Simon_F]

Re: My 1st half stack, how to hook it up?

How much power would I be losing running into the 16ohm input of the marshall?

I have a solid state Tech 21 Trademark 60 combo (60 watts) that has an 8 ohm external speaker jack. When I asked Tech 21 whether it was safe to connect this to a 16 ohm 4x12, their answer was "yes, but the amp will only deliver about 40 watts". I don't know whether that ratio is scaleable, i.e. whether a 300w 8 ohm SS amp will deliver 200w into 16 ohms.

 

[Reload in 5]

Re: My 1st half stack, how to hook it up?

what exactly does it say around the speaker outputs ? does it say something like "4 ohms total" ?
exact words would help here.

 

[Danglin' Fury]

Re: My 1st half stack, how to hook it up?

Impedence matching ( 8 ohm out to 8 ohm in) is ESSENTIAL for maximumpower transfer from source to load (speakers). I wouldnt run mismatched impedences for very long as it is probably detrimental to either the amp or the speakers. Some would disagree but manufacturers say to match impedences for a reason. The parallelled outs means that both outs are at the same ohm rating so if you send speaker cable from both of those to the stereo jacks on the cab, it should be good and you will be getting maximum power from your amp. Why shortchange yourself?:smokin:

 

[Empty Pockets]

Re: My 1st half stack, how to hook it up?

not to hijack the thread or anything, but am I to understand that running my 4ohm Bassman head into my 16ohm Sunn cabinet is UNsafe? Or it just makes the amp deliver less power? I've been usin the cab like this for a while and it doesn't seem like it's hurtin anything...but the less power thing would make sense.

-X

 

[Simon_F]

Re: My 1st half stack, how to hook it up?

am I to understand that running my 4ohm Bassman head into my 16ohm Sunn cabinet is UNsafe?

A tube amp should ALWAYS be run with a matching load, otherwise you risk seriously damaging it.

 

[D-EJ915]

Re: My 1st half stack, how to hook it up?

That head puts out 300 watts at 4 ohms for the record.

Unfortuntely Randall hasn't put up the manual for it, which is weird, so I can't tell you how to set it up.

ok this is how it is:

just hook a cable from one of those into the 4 ohm jack on the cab