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Speaker to Amp Matching

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Speaker to Amp Matching

Postby tomdejoliet » Mon Mar 15, 2021 5:26 pm

I need recommendations on selecting passive PA speakers to match my power amp. The system will be used to power my guitar amp emulator.

I purchased a Pyramid PA800X power amplifier with the following specs:

400 watts x 2 into 8 ohms (2 x 125 watts rms)
800 watts x 2 into 4 ohms

https://mobile-emotions.com/pyrpa8800wat.html

Thanks in advance!
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Re: Speaker to Amp Matching

Postby Sam Spoons » Mon Mar 15, 2021 5:48 pm

I'd pair it with a couple of 8 ohm speaker cabs with at least 250 watts handling capacity, more will be safer with electric guitar as saturated distortions carry a lot (relatively speaking) of HF energy.
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Re: Speaker to Amp Matching

Postby Wonks » Tue Mar 16, 2021 10:29 am

Do you need stereo? If you only want mono (as it is a guitar system) then I'd get a powered speaker. 125W for a PA speaker isn't going to get you a particularly loud system. Of course you might not want it too loud. But if you do than I'd look elsewhere. That amp looks to be a 3U rack amp, and with that power output, is going to be a heavy, conventional class AB amp. It's also only got banana plug connections, which are fine for a fixed installation, but if you are regularly gigging, then they aren't the most robust connectors and are fairly easily pulled out if someone accidentally catches the speaker lead with their foot or whatever.

From reading the manual, it doesn't look like the amplifier is grounded, but has provision for an external ground connection. http://pdfstream.manualsonline.com/2/2f ... 87975a.pdf

The PA600X is shown in its rear-panel diagram as having a fixed two-core power lead, with no ground connection. Although the PA800X and above use an IEC connector, I'd be very concerned that the PA800X was constructed in a similar way with no safety ground connected. If not, then with an internal fault developing, it has the potential to kill and I'd never even consider using an amp like it. The grounding is easy to test with a multimeter, seeing if there is continuity between the ground prong in the connector and the amp casing. It should also connect to the ground stud (if the amp is designed to provide aground for external ungrounded equipment). The manual is certainly unclear on this.

I'd really suggest looking at an active PA speaker, say an Alto TS310 or TS312. These are the same units as Headrush sell as their powered FRFR guitar cabs, but a bit cheaper without their badging. They'll go a lot louder than you should ever need to go. Far more convenient and much lighter and less bulky than that power amp and separate speaker(s). $249 at Guitar Center for the 10", and $299 for the 12".
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Re: Speaker to Amp Matching

Postby Sam Spoons » Tue Mar 16, 2021 11:43 am

+1, :thumbup:
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Re: Speaker to Amp Matching

Postby uselessoldman » Tue Mar 16, 2021 12:51 pm

No XLR in and only nanaplugs out, appears to have no mono switch option and no idea if jack ins are balanced or not, I would guess NOT.

A few options
Get a 4x12 with mono/stereo option then you can run pairs from the amp outs. You will have to alter the loudspeaker cable connectors you ain't gonna any find off the shelf, no big deal just make sure you get the wires right way round. A similarly configured 2x12 you could do the same. If your lucky you can sometimes puck them up pretty cheap just keep your eyes open.

If you really do have to have PA speakers, best see what is available locally second hand first.

If you can find one of those Harley Benson 2x12 cabs I think there really good, they have the mono/stereo switch and as standard come with G12T-75s and the V212 model has V30s. I have one and love it although I have now swapped out the V30s for G12H-100s and use it as you do with vst/amp sims. Then I got the chance of another at even sillier money so bought that to it was unloaded so I whacked in some G12Ts. They are ply cabs well made with good guitar speakers.

erm I was going to suggest taking it back and buying a second hand QSC RMX 850 but I though I would be nice, but Wonks has basically said it for me :)
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Re: Speaker to Amp Matching

Postby Wonks » Tue Mar 16, 2021 2:08 pm

According to the manual, it has got balanced 1/4" TRS inputs.
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Re: Speaker to Amp Matching

Postby ef37a » Tue Mar 16, 2021 11:19 pm

The manual refers to "speaker terminals" which I take to mean 'binding posts'? That is the most usual speaker connection on big amps with a 4mm plug in the centre.

These are fiddly to wire and a potential short hazard. I suggest terminating the speaker cables* in crimp or soldered 'U' connectors that can just slide under the pots. You might find suitable terminals at Halfords?

*And if you have none yet, Orange garden equipment cable is cheap and well up for job.

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Re: Speaker to Amp Matching

Postby Wonks » Tue Mar 16, 2021 11:32 pm

ef37a wrote:You might find suitable terminals at Halfords? .

I don't think they have Halfords in the US, Dave.

But you'd expect that most auto or electrical stores will probably have some.
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Re: Speaker to Amp Matching

Postby ef37a » Tue Mar 16, 2021 11:41 pm

Wonks wrote:
ef37a wrote:You might find suitable terminals at Halfords? .

I don't think they have Halfords in the US, Dave.

But you'd expect that most auto or electrical stores will probably have some.

Watch it Wonky or I might get "curmudgeonly" again! Where doe it say "US"?

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Re: Speaker to Amp Matching

Postby Wonks » Wed Mar 17, 2021 9:40 am

The fact the price in the amp web page is in $.
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Re: Speaker to Amp Matching

Postby ef37a » Wed Mar 17, 2021 9:43 am

Wonks wrote:The fact the price in the amp web page is in $.

Ah! "Elementary my dear Wonks"


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Re: Speaker to Amp Matching

Postby Wonks » Wed Mar 17, 2021 9:50 am

Indeed. And just to confirm, the 'About us' section of the website list their address as:

Mobile Emotions
3820 Oceanic Dr #308
Oceanside, CA 92056
800-258-0946 (9-5pm Pacific Time Zone)

Now it's time to doff the deerstalker, smoke a pipe and play the violin...
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Re: Speaker to Amp Matching

Postby ef37a » Wed Mar 17, 2021 10:30 am

https://uk.rs-online.com/web/p/fork-ter ... s_Whoop+(2)-_-8046962&matchtype=&aud-659911584228:pla-329921638962&gclid=Cj0KCQjw0caCBhCIARIsAGAfuMyJvTY0MD7u2Dc51jur2AEHKSfcqCojfciaTTgZ-YTWKIYrdv3LCnQaAnQxEALw_wcB&gclsrc=aw.ds
Phew! Took some finding but above is the sort of thing I mean. Naturally you will need bigger than M3.5, at least M5 and maybe bigger.

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Re: Speaker to Amp Matching

Postby AlecSp » Wed Mar 17, 2021 5:42 pm

ef37a wrote:Watch it Wonky or I might get "curmudgeonly" again! Where doe it say "US"?
Wouldn't it make life so much easier if everyone had their location (or, at the very least, their country) in their profile. It would avoid all the second guessing and assumptions. Hint, to the OP....

ef37a wrote:Phoenix Contact, C-FCI 2.5/M3.5 Uninsulated Crimp Spade Connector, 1.5mm² to 2.5mm², M3.5 Stud Size, Blue
Phew! Took some finding but above is the sort of thing I mean. Naturally you will need bigger than M3.5, at least M5 and maybe bigger.
And, in the same vein, you may well find that M3.5 and M5 mean nothing in the US and have to be translated across to a local prosaic screw thread standard.
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Re: Speaker to Amp Matching

Postby ef37a » Wed Mar 17, 2021 6:25 pm

AlecSp wrote:
ef37a wrote:Watch it Wonky or I might get "curmudgeonly" again! Where doe it say "US"?
Wouldn't it make life so much easier if everyone had their location (or, at the very least, their country) in their profile. It would avoid all the second guessing and assumptions. Hint, to the OP....

ef37a wrote:Phoenix Contact, C-FCI 2.5/M3.5 Uninsulated Crimp Spade Connector, 1.5mm² to 2.5mm², M3.5 Stud Size, Blue
Phew! Took some finding but above is the sort of thing I mean. Naturally you will need bigger than M3.5, at least M5 and maybe bigger.
And, in the same vein, you may well find that M3.5 and M5 mean nothing in the US and have to be translated across to a local prosaic screw thread standard.

Are you suggesting our American cousins cannot divide by 25.4?

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