Amp to Board Compatibility ?

Old Fart · #1 09-20-2011, 01:24 PM

I've got an Ampeg BA-115HPT (preamp tube, 220 watts). The band is loud. I probably need a different setup for long term, as I am accustomed to being able to win any volume contest that arises. In the meantime, this amp did a pretty good job on Saturday, but volume was at 8.

The amp has a 3-prong output plug that my rhythm guitarist called a "low impedance" out. We ran a cable to one of the inputs on the Peavey PA box (this drives four 15's and two horns), and got a nasty, crackly, ugly amp-distortion sound. Turning the gain knob on the PA nearly all the way down stopped it, and I think the sound guy had me going only through the monitors, not the big PA speakers.

Can anybody tell me any information, or guesses, as to what this problem is?

steve_rolfeca · #2 09-20-2011, 01:32 PM

I know that at least some other Ampeg products have unusually strong DI outputs, and no means to adjust the DI output (some amps have a volume control, or at least a line/mic level switch, beside the DI out jack).

As long as you were able to lower the gain on the mixer enough to prevent the distortion, I wouldn't worry about it. In a lot of cases, a nice strong signal that doesn't require much "make-up gain" from the mixer, makes for a cleaner, quieter feed.

JimmyM · #3 09-20-2011, 01:34 PM

Steve is right. I used the DI of my Micro VR on a gig last night, and the soundman had to turn it down on the board because it was too hot for his normal settings, especially because I like to crank the gain to get some overdrive, but once he did that, it was fine.

will33 · #4 09-20-2011, 01:34 PM

That's your DI. It's made to run you into the board. If it's making nasty noises, it either needs to be fixed or the gain was just too high. Built in amp di's should have a knob to control the level of that output going to the board but not all do and some are fixed too hot. It should also have a ground lift switch and a pre/post switch but again, not all do. The ground lift is for buzz problems, the pre setting sends a dry signal from your bass, the post sends the amp flavor and settings like bass boost or whatever. Start with the gains all the way down on the amp and board, hook it up and bring the gains up slowly. If adjusting things doesn't make the problems go away you've got either a bad di on the amp, a bad cable, or a bad channel on the board.

Old Fart · #5 09-20-2011, 01:45 PM

Thank you. I will be playing with it, next rehearsal. Hopefully, can get it to work well in the meantime.

For long term, I'd like to just have enough power and speakerage to solve any volume problem using my rig. That'll mean running this output plug to another slave amp and speaker box. Or a whole new setup. I have a lot to consider, and I'll take my time. I appreciate you guys' 'input.' (pun intended)

will33 · #6 09-20-2011, 01:51 PM

You should use a plug labeled line out or preamp out to slave to another slave amp. The 3 prong plug you're talking about looks like a microphone plig and is a balanced low impedance line made for plugging in a mixing board channel just like a microphone.

RickenBoogie · #7 09-20-2011, 03:01 PM

+1 and another alternative would be to use a dedicated DI box, instead of the one from the amp, for now.

BassmanPaul · #8 09-20-2011, 03:07 PM

Quote:

Originally Posted by Old Fart

The amp has a 3-prong output plug that my rhythm guitarist called a "low impedance" out. We ran a cable to one of the inputs on the Peavey PA box (this drives four 15's and two horns), and got a nasty, crackly, ugly amp-distortion sound. Turning the gain knob on the PA nearly all the way down stopped it, and I think the sound guy had me going only through the monitors, not the big PA speakers.

Can anybody tell me any information, or guesses, as to what this problem is?

There is no problem. The average mixer is accustomed to a mic level input. The DI out is often at a line level. The distortion you got was caused by overdriving the input of the mixer channel. Turning down the gain for that channel is exactly what you should do. That's what the gain control is for.

C47 · #9 09-20-2011, 03:17 PM

I have a similar ampeg combo and the xlr output is a bit hot.
Helps to have the board turn the gain way down and set the
crossover for the subs to 100HZ. The regular monitors do get overloaded if there are no sub woofers

My PF500s DI output is even hotter still but it has a 40 db pad
switch which damps it almost too much. But with a 410HLF cab
I rarely need to run to the PA because it rumbles thru everything
by itself.

Old Fart · #10 09-20-2011, 04:11 PM

Okay so, in a nutshell, can I use this three-prong, balanced low impedance output thingie to connect to a slave amplifier, so I can add another box (like....a 410)? Or is it not designed for that? I just wonder what my options are.

Yes, I can see that we can still run my amp through the PA amp, but we just have to keep the gain turned way down. I think that is what I am hearing.

This board rocks.

will33 · #11 09-20-2011, 04:30 PM

Quote:

Originally Posted by Old Fart

Okay so, in a nutshell, can I use this three-prong, balanced low impedance output thingie to connect to a slave amplifier, so I can add another box (like....a 410)? Or is it not designed for that? I just wonder what my options are.

Yes, I can see that we can still run my amp through the PA amp, but we just have to keep the gain turned way down. I think that is what I am hearing.

This board rocks.

Apparently, the gain on your DI (the 3 prong thingie) is fixed meaning you can't adjust the signal level coming out of that thing on the bass amp. So...hook that up to a channel on the mixing board with a mic cord. Start with the gain knob (or "trim" knob on the board, the one at the top) all the way down. Put the slider (at the bottom of that channel) somewhere in the middle, then start turning up the gain (trim) knob until you get a good level without clipping it, then use the slider at the bottom of that channel for finer adjustments.

For slaving to another amp you should have a separate 1/4" jack somewhere on that amp labeled "line out" or "preamp out". Run a regular guitar cord from that jack to a jack labeled "line in" or "poweramp in" on the slave amp if it's another bass or guitar amp or the one labeled "input" if it's a regular poweramp like a PA system uses to drive the second speaker cabinet. The slave amp is then only providing power to the second cabinet and all the tone controls on the first amp will control all the speakers.

If you're running the DI (3 prong thingie) into the mixing board, that makes it so the PA is carrying your sound out front and there's really no need for slave amps and more speakers. Your bass rig is now a stage monitor for you and the rest of the band, the audience out front is now hearing you from the PA.

will33 · #12 09-20-2011, 04:42 PM

I hope you don't think I'm talking down or something, man....just trying to make it understandable. Something about your username (which I like) tells me you're from an era when there weren't PA's that could handle everything and backline rigs with slave amps and piles of speakers carried the gig and what PA there was was for getting vocals and drums out there the best they could.

If your current PA does not have subwoofers, you may want to take some stress off it by doing it the old way and just let it do vocals and drums the best it can.

-Will

Old Fart · #13 09-20-2011, 04:45 PM

There is no "Preamp Out" on this amp. There is a 1/4" "Headphones" jack, but I suspect that turns off the 15 speaker.

Thanks for the info. I'm learning.

will33 · #14 09-20-2011, 05:04 PM

If it's new enough to have a headphone jack, there should be something on there for connecting to another amp. Check the owners manual, it should be online if you don't have a copy. If not, you may have to make up a "Y" cable or get an adapter so you can just plug in the front of 2 amps. If it has a jack labeled "ext. cab", that's for hooking up another speaker. If the DI out is hot, it might be enough to drive a slave amp, not sure but that would eliminate the possibility of running it to the PA which is always the better option if it's a decent PA.

Search "ampeg BA-115HPT manual" and download it. If you have more questions, post them.

Ok, I looked at the manual. It just has the di which says it can go to the board or another amp but not both at the same time. Your master volume control on the amp affects this so if you got the amp cranked up, you're likely overdriving the mixing board channel. Best thing to do would be to run that to the PA, let that play to the audience and keep the amp volume a bit lower just to cover you and the band on stage. You can't adjust both independently and you can't both a slave amp and go to the PA at the same time.

will33 · #15 09-20-2011, 05:23 PM

I've played those amps before, they can sound pretty dang good on their own but they need more ins and outs and independent controls to make them versatile and expandable enough to use in a lot of different gigging situations. They do have an ampeg sound to them and they are loud enough to play with a drummer but you are limited as to what you can hook up and do beyond that.

bassmeknik · #16 09-20-2011, 07:18 PM

All these TBers with advice should be looking up the amp mentioned by the OP. Then they would know what will33 said and realize the OP has just experienced a shortcoming in this design.

If at all possible just use the DI out (3 prong thing is called an XLR connector) ran to a mic channel on your board (start with it turned all the way down as in the earlier post)

Despite limitations in versatility the Ampeg HP combos rock. Use your front of house PA for the bass sound and the amp as a stage monitor. The tube pre-amp is used for the FOH sound (XLR output) as well as the main speaker in the combo so if your sound man can trim your amps output level I would use it or plan on spending at least $100 to buy a better DI box that does the same thing but has a variable output.

thedevilisbad · #17 09-20-2011, 09:04 PM

Quote:

Originally Posted by JimmyM

Steve is right. I used the DI of my Micro VR on a gig last night, and the soundman had to turn it down on the board because it was too hot for his normal settings, especially because I like to crank the gain to get some overdrive, but once he did that, it was fine.

Sounds like he needed to have that channel "padded". This is what I have to do with Ampeg's. They sound pretty good directly out to the board (or at least good enough).

Jerrold Tiers · #18 09-20-2011, 10:08 PM

The DI out on BA-115HPT is basically "line level" and not "mic level".

If treated as that on the board, it should be OK..... but not all boards have a like level in..... And Peavey, at least some older ones are a bit notorious for not having any way to turn a too-hot level down before the fader. You can add gain, but not turn down, on many older units.

will33 · #19 09-20-2011, 10:22 PM

Now it's getting more bizzare, a line level out with a mic (xlr) plug that the manual states is controled by the amps master volume. Is this sort of an add on feature hoping to add some value but not really incorporated in a "makes sense" sort of functioning way? Seems confusing.

Old Fart · #20 09-20-2011, 11:03 PM

The name of this three-pronged, high impedance, line level plug as printed on the panel next to the plug is "Line Out". So I think that solves the mystery. And the Peavey may not have a line level in. I'm getting it.

Our PA has two fifteen-inch speakers on each side, so I expect it to be capable of handling the bass. And that's the best solution, I year. Yes, last time I played bass the PA was for voices and some drums. Horns even. But not bass. We were on our own. That's why God gave us the SVT.

If I added a cabinet, using this "Line Level" output, I wouldn't be able to plug into the PA, right? Or may be the other amp would have an output. Just hoping to understand. You guys are great.