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Author Topic: Using MP1 without power amp, through 1x12'' cab - will it break the MP1?  (Read 8040 times)

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matei

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Hi all,

I just accidentally discovered that I can use my ADA MP-1 direct into a speaker cab w/o a power amp. It isn't very loud, but loud enough to rock and roll in the house without bringing the walls down.

Does anyone else here do this? 

It sounds pretty good too. I'm using it with a CAE 1x12'' cab. Literally just plugged in output A into my speaker cab, it was a mistake while re-wiring my rack, started strumming to see if any signal was coming out and noticed my power amp was switched off.

Someone on another forum mentioned that I might risk damaging the output stage of the preamp as it might be drawing far too much current from the outputs with a guitar speaker load...  figured the best place to ask about this possibility would be here, as you guys know the ins/outs of the MP1 better than anyone else!

The tone is fabulous, figures - I was just testing things out as I had planned on selling the MP1, but it sounds so good that I've changed my mind.  :-)  Hope it is safe to use this way, as the volume is perfect for practicing, recording etc.
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rnolan

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Hey matei, MJMP will know better than me but while it sounds ok to your ears, it's a bad idea.  Will it damage your MP1 (maybe/probably), it's not designed to run a speaker load/current.  Run the MP1 into your poweramp > cab and turn down the ADA output level knob to suit the volume you want.  Then it will sound just as good (if not better) and not blow anything (i.e. MP1) up.  And, as you say, the tone is fabulous :thumb-up: >:D
Cheers Richard
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matei

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Thanks for the guidance. 

This is my second time around with the MP1... I bought one in 1989-90, to replace my old Marshall heads.  Got tired of lugging them around and blasting them on 10 just to get good tone, plus club owners hated me.  ;-)

I couldn't get enough "oomph" to compete with the other guitarist however, who still used a 50-watt Marshall head.  This was in spite of me having a massive 200 watt valve Mesa Boogie power amp.

I bought another MP1 from someone in Switzerland, it was untouched, the 2.01 version, but up until recently I wasn't too thrilled with the tone.  I haven't found a power amp that I'm happy with, and direct (using speaker sims and/or impulses) didn't sound convincing.

I'll keep looking now though, as this tone accident has re-inspired my faith in the MP1  :-)
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RobbHell

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Others have done this for the exact reason you mentioned Rock N Roll styles. The MP1 is a preamp and does require a poweramp for louder sounds. This WILL NOT  damage your MP1. Its works for you and you like it for your needs then by all means rock it.
You might notice excess noise and clipping because your using the Master to drive speakers.

Have fun and keep us update.
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matei

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Thanks guys.

Very cool by the way that there is such a helpful community to support this interest, restores faith in humanity.   :) :banana-guitar:
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MarshallJMP

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Normally the min load for a NE5532 is 600 ohms.It will work with lower loads but it won't work correctly anymore,you won't have much voltage swing left since it can't supply the current (the output is protected).But i think if you use it like this it will eventually fail,my 2 cents.
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RobbHell

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MJMP makes a good point. Have you thought about maybe modding your mp1 less gain for those Rock styles.
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RobbHell

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These nothing wrong with Low Wattage power amps. I've 15 watts straight crush through a single 15.
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El Chiguete

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These nothing wrong with Low Wattage power amps. I've 15 watts straight crush through a single 15.

What 15w power amp you have?
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Before you see the light, you must die!!!

'87 Kramer Stagemaster Custom
'81 Kramer Pacer Standard
custom made Les Paul
ADA MP1
Rane MPE 28
Lexicon MPX-G2
Epiphone Valve Jr. moded!!!

AFFA
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RobbHell

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A friend picked up a custom made Class A 15 watt. Came from NAMM in 2011 all it had written on it was Rat Amp.
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El Chiguete

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What are the specs?
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Before you see the light, you must die!!!

'87 Kramer Stagemaster Custom
'81 Kramer Pacer Standard
custom made Les Paul
ADA MP1
Rane MPE 28
Lexicon MPX-G2
Epiphone Valve Jr. moded!!!

AFFA
Support Your Local 81

rnolan

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What are the specs?
It likes cheese and drain pipes LOL.  I used to have a pair of Mullard 20w mono blocks for my stereo (class B though (2 x EL34s)), nice amps.
Class A, one tube does both +ve and -ve parts of the signal, very clean, no crossover distortion, audiophiles love them
Class B one tubes does +ve, other tube does -ve (fed by a phase splitter tube to split the signal into +ve/-ve) like the majority of tube guitar amps.

There are quite a few decent power amp options for MP1 that work well (check a few posts), my first love is the ADA B200s, I now use a Carvin TS100 all tube 50/50, a bit heavy to lug but a great sounding amp and you can but them new (also a presence (6khz) boost to help get more cut through).  You can run either of these options really soft, or blow the windows out  >:D
I had a similar experience with my '72 Marshall 50, couldn't be in the same room at the vol I needed for a decent tone, but these are pre master vol.  I ran it with a Tom Schultze Power Soak (between amp and cab) so I could crank it but not annoy the publican to much.  MP1 was a god send, and they sound heaps better as well.
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