15" cab for PJB Briefcase

[agedhorse]

How are you connecting the Marshall and PJB together?

I suspect that you have come to an incorrect conclusion.

 

[Makten]

How are you connecting the Marshall and PJB together?

The last pedal in the chain has two outputs. So the same signal is fed to both. I've tried to split them with different frequency ranges (I do that for overdrive earlier in the chain), but it actually didn't sound as good.

I suspect that you have come to an incorrect conclusion.

?

 

[agedhorse]

Have you tested to determine if the polarities are the same at the speakers?

If the electronic polarity is reversed through one of the two amps, you will lose low frequency response and volume.

 

[Makten]

Have you tested to determine if the polarities are the same at the speakers?

If the electronic polarity is reversed through one of the two amps, you will lose low frequency response and volume.

My comment about lack of bottom end was with only the 15" connected, so that is not the issue. There is no apparent phase problem when switching on the little Marshall either; it just adds a tad of sweet upper mids and treble (Celestion Gold in there).

Edit: And to be even more clear, the internal speakers of the Briefcase gives about the same amount of bottom end. So it makes sense to think that the amp cuts the lowest frequencies a bit higher than other amps, since the speakers are so darn small anyway.

 

[agedhorse]

My comment about lack of bottom end was with only the 15" connected, so that is not the issue. There is no apparent phase problem when switching on the little Marshall either; it just adds a tad of sweet upper mids and treble (Celestion Gold in there).

Edit: And to be even more clear, the internal speakers of the Briefcase gives about the same amount of bottom end. So it makes sense to think that the amp cuts the lowest frequencies a bit higher than other amps, since the speakers are so darn small anyway.

When you connect the 15” cabinet and there is a lack of bottom end, that is the PRIMARY symptom of polarity reversal between the two signal paths.

That’s why I said what I did.

 

[Makten]

When you connect the 15” cabinet and there is a lack of bottom end, that is the PRIMARY symptom of polarity reversal between the two signal paths.

That’s why I said what I did.

Sure, I know that very well. But that is not the case here.

 

[DJ Bebop]

Sure, I know that very well. But that is not the case here.

Have you tried just the 15 with the suitcase speakers disconnected yet?

Oh now I see you did…

 

[Makten]

Have you tried just the 15 with the suitcase speakers disconnected yet?

Oh now I see you did…

View attachment 7283819

Yes, there is only one speaker output, so I can't run the internal ones and the new cab at the same time.

 

[Wasnex]

Yes, there is only one speaker output, so I can't run the internal ones and the new cab at the same time.

Since the internal speakers are 4 ohms and the amp is 4 ohms minimum it should not be attempted.

 

[agedhorse]

Sure, I know that very well. But that is not the case here.

How do you know that very well? Is it that your Marshall amp has no low end and therefore is an unsuitable choice?

I’m trying to help, but now I’m not sure that’s what you really want.

 

[Wasnex]

How do you know that very well? Is it that your Marshall amp has no low end and therefore is an unsuitable choice?

I’m trying to help, but now I’m not sure that’s what you really want.

The weak low end occurs with the 15 playing by itself.

 

[agedhorse]

The weak low end occurs with the 15 playing by itself.

Understood. I was addressing the combination and when using it with the Marshall amp.

I’m thinking that overall the PJB may just be the wrong tool for the job, but what do I know, right?

 

[Makten]

How do you know that very well? Is it that your Marshall amp has no low end and therefore is an unsuitable choice?

I’m trying to help, but now I’m not sure that’s what you really want.

Understood. I was addressing the combination and when using it with the Marshall amp.

I’m thinking that overall the PJB may just be the wrong tool for the job, but what do I know, right?

I meant that I know very well how out-of-phase problems occur (and how to solve them).
The little Marshall only adds upper mids and high end, and makes no difference at all at the bottom. I used it a lot when I ran the internal PJB speakers, but for some reason I less inclined to do so with the Ampeg, despite the latter giving less high frequencies.

I'm pretty sure the lacking bottom is because of the amp. I've always had the EQ "scooped" even though I generally don't like scooped sounds, so it seems very mid heavy by default.

The PJB is great, and I wanted to try how it sounded with a larger cab before changing to a different amp as well. It made a very nice difference and I like the results a lot better than with the internal speakers. I don't see why it would be the "wrong tool for the job". The 110 Watts is plenty enough.