Using a guitar amp? ADVICE NEEDED!!!

[MOTORHEADBANGER]

Yesterday I purchased a 1973 Ampeg GUITAR combo amplifer for $110 and a Big Muff. It is called the G412 and is one of the guitar amp versions of the 70's B410 combo and the B115 combo. It has four 12" speakers, two channels, reverb, tremolo, and is VERY loud for 120watts. It sounds good with my Aria Pro II SB-R60 bass, but I want to know what you guys would recommend I do with it. It has virtually the same head in it as the B410 so is it safe to gig with? Would I damage it at high volumes?

[lowfreq33]

It's possible you could blow the speakers. One, it's old, they may be on the way out anyway. Two, guitar speakers aren't necessarily designed to handle the larger amount of speaker excursion that low frequencies at high volumes can produce. It could be fine, I'd just be careful about how hard you push it.

[MOTORHEADBANGER]

Also I was wondering if I could put bass speakers in it. The head is eight ohm so maybe I could put in the speakers from an 8ohm 4x10 bass cabinet or even two fifteens. Its big enough. It's close to five feet high, and at least 2.5 feet wide.

[Jason P Bass]

Originally Posted by MOTORHEADBANGER

Also I was wondering if I could put bass speakers in it. The head is eight ohm so maybe I could put in the speakers from an 8ohm 4x10 bass cabinet or even two fifteens. Its big enough. It's close to the same height as a Fender P-bass, and super wide.

Hm, I'm wondering the same thing, but for different reasons.

My thoughts:

1) A person could put bass speakers in that cabinet. The performance would probably not be optimal.

2) The speakers would cost as much as a brand new low end bass cabinet, and under these circumstances, a brand new low end cabinet would probably work better.

3) Your units of measurement ("Fender P-bass x super wide") have blown my mind. It's no accident that I said "a person" in Thought 1) even though you asked if you could do it. I simply cannot answer your more specific question.

Honestly, if it's a cool vintage Ampeg, do not mutilate the cabinet. Match the head to something else and give it a whirl.

[MOTORHEADBANGER]

Originally Posted by Jason P Bass

Hm, I'm wondering the same thing, but for different reasons.

My thoughts:

1) A person could put bass speakers in that cabinet. The performance would probably not be optimal.

2) The speakers would cost as much as a brand new low end bass cabinet, and under these circumstances, a brand new low end cabinet would probably work better.

3) Your units of measurement ("Fender P-bass x super wide") have blown my mind. It's no accident that I said "a person" in Thought 1) even though you asked if you could do it. I simply cannot answer your more specific question.

Honestly, if it's a cool vintage Ampeg, do not mutilate the cabinet. Match the head to something else and give it a whirl.

Sorry about the interesting units of measurement. I tend to have frequent "stupid attacks." I was thinking about getting a second cab. The head is easily removable. I have an old eight ohm 15"speaker in a DIY cabinet that I could use. Any thoughts?

[Jason P Bass]

Yeah, don't use the guitar speakers. It's very possible that you'll destroy them, and if you don't, it won't sound very good anyway. If you want to practice at low volumes - no harm no foul.

I would use an 8 Ohm bass cabinet if I were you.

[MOTORHEADBANGER]

Would there be any problem installing 4 32ohm 10" bass speakers into this amp? It looks like the head is removable and the cab is connected to it with a normal speaker cable. It seems like it would be easy to install bass speakers. I practiced with the amp this morning, and it has a very clean and vintage tone that is unmistakenly Ampeg that I love. It also is very powerful especially for 120 watts. I would prefer to keep the amp and use it do to its sound and its vintage, yet intimidating look.

[Lo-E]

No problem at all, but you'd be better off using four 8 Ohm speakers. Wire them so that you have two pairs in parallel, then put the pairs in series with each other.

I hope that made sense....

You won't hurt the amp.

[Pilgrim]

Your best option is to sell the cab and get one made for bass. You'll send more on speakers than a used cab will cost. Also, if you put bass speakers into the cab, you can't put any old speaker - you need a speaker compatible with the interior volume of that cab. WAY too much trouble to achieve this, and almost certainly too expensive.

And yes, if you push that guitar cab very much, you will destroy the speakers - bass requires more speaker movement than guitar and they will go bye-bye. So until you get an actual bass cab, keep the volume turned down.

[MOTORHEADBANGER]

Originally Posted by Lo-E

No problem at all, but you'd be better off using four 8 Ohm speakers. Wire them so that you have two pairs in parallel, then put the pairs in series with each other.

I hope that made sense....

You won't hurt the amp.

Why four 8 ohm speakers. If the head of my combo has an 8 ohm impendence, wouldn't four 8 ohm speakers add up to 2 ohms?

Also, a friend gave me a deal on a 4x10 bass cab that is rated at 8 ohms. I was thinking I could take those speakers out and install them into the Ampeg combo and put the guitar speakers in the bass cab, that way it would also give me a cool guitar cab if I ever need one. Would this work? FYI the bass cab is big enough to hold four 12's.

[lazyone2]

Why not just use the bass cab. It seems like your going to do alot of work and the results could be far less the stellar.

[MOTORHEADBANGER]

Originally Posted by lazyone2

Why not just use the bass cab. It seems like your going to do alot of work and the results could be far less the stellar.

True. I could just make a casing for the head. Then I could keep the combo's cab for practices at home. I was mainly wondering if it could be done without ill effects, since the combo is just a head and cab in one.

[nysbob]

Originally Posted by MOTORHEADBANGER

Why four 8 ohm speakers. If the head of my combo has an 8 ohm impendence, wouldn't four 8 ohm speakers add up to 2 ohms?

It would if you wired them all parallel - he was talking about wiring them in series-parallel. Wire each pair in series, then parallel them. That's how you get four speakers working at the impedance of one.

[lowendgenerator]

This probably isnt what you want to hear, but why not sell it for a profit and buy a real bass amp? You got that amp for a real good price, make a few bucks on it and get a head for that 410 cab... Don't destroy vintage gear.

[MOTORHEADBANGER]

Since the head of the combo amp is removable, I could just use it with the 4x10 for gigs and keep the loaded body of the combo at home for practices.

[lowendgenerator]

That IS an option of course, but when you say the head is removable, what do you mean? Does it have a shell around the chassis? I'm not quite familiar with early 70's Ampeg stuff. And on a side note, 150w may sound loud at home, but thrown in a band mix, it might not be enough power. The only way to know is to try I suppose. Just please don't mutilate/alter vintage gear lol.

[MOTORHEADBANGER]

Originally Posted by lowendgenerator

That IS an option of course, but when you say the head is removable, what do you mean? Does it have a shell around the chassis? I'm not quite familiar with early 70's Ampeg stuff. And on a side note, 150w may sound loud at home, but thrown in a band mix, it might not be enough power. The only way to know is to try I suppose. Just please don't mutilate/alter vintage gear lol.

The head slides out of the combo's body like a tray. The chassis of the head is completely covered, but I am going to make a shell/sleeve to put it in when on the road. Also, I have used quite a few heads, but I must say that this is definitely the loudest for its rating. It's supposedly rated at 120 watts at 8 ohms but, it'll drive a 300 watt 8 ohm 4x10 cab like none other with the volume at three. Also if I ever get tired of the head I could always put it back in the combo, put a few bucks into it for restoration, and sell it for a good $450.

[i_got_a_mohawk]

The reason it seems so loud is because it isn't producing near the low-end of a bass amp. Try any 120 watt guitar amp through a 4x12, they are all loud

[60's Bluesman]

i wouldnt use it man, you will blow it out