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Do I need different cabs?


Bobthedog
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I am playing my Blue Rock amp (1000w @ 4ohms, 500w @ 8ohms) through 2 x TCE RS212 cabs (400watt, 8 ohm impedance). The cabs are connected to the amp via a speakon cable from each cab into the back of the amp.

The volume is a lot lot quieter than from my RH750 amp.

If I wanted to get the max from the Blue Rock do I need to buy some 4ohm cabs? Am i only getting 250 watts from each cab due to them being 8ohm cabs? Should I daisy chain the cabs rather than parallel them?

As you can guess watts and ohms are still a mystery to me, despite reading the other threads on here. All i know is that this Blue Rock is extremely quiet compared to my RH750 but is supposedly more powerful.

Edited by Bobthedog
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Try connecting the cabs you have the other way (one lead from the amp to cab 1, lead from cab 1 to cab 2) and see if that makes a difference. That should be parallel wiring and will present a 4 ohm impedance to the amp. Check the manual for your amp to see if there are any notes about how the speakon outputs are wired.

I wouldn't get 2x 4 ohm cabs. In parallel they'll appear as 2 ohms (which I'm guessing your amp will be unhappy with).

If by "daisy chain" you mean connect in series, I wouldn't. That will result in the impedances being added together to give you 16 ohms and you'll be even quieter.

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Which version of the blue rock do you have? There are two, one can run at 2.7 ohms and one only goes down to 4 ohms...

I can't imagine why either version of that head wouldn't be loud enough through 2x 212s though :blink: I have the blue soul which has a slightly lower power rating at 4 ohms and it's very very loud running through a single 210... something strange afoot methinks... :blink:

Edited by CamdenRob
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[quote name='neepheid' timestamp='1459330946' post='3015433']
Try connecting the cabs you have the other way (one lead from the amp to cab 1, lead from cab 1 to cab 2) and see if that makes a difference. That should be parallel wiring and will present a 4 ohm impedance to the amp. Check the manual for your amp to see if there are any notes about how the speakon outputs are wired.

I wouldn't get 2x 4 ohm cabs. In parallel they'll appear as 2 ohms (which I'm guessing your amp will be unhappy with).

If by "daisy chain" you mean connect in series, I wouldn't. That will result in the impedances being added together to give you 16 ohms and you'll be even quieter.
[/quote]

[color="#0000cd"]I have tried the other way amp to cab to cab but will give it another go. Thank you. I am thinking of just one 4ohm cab as that will remove any confusion re ohms on my part![/color]

[quote name='CamdenRob' timestamp='1459331679' post='3015445']
Which version of the blue rock do you have? There are two, one can run at 2.7 ohms and one only goes down to 4 ohms...

I can't imagine why either version of that head wouldn't be loud enough through 2x 212s though :blink: I have the blue soul which has a slightly lower power rating at 4 ohms and it's very very loud running through a single 210... something strange afoot methinks... :blink:
[/quote]

[color=#0000cd]Thank you too. The Blue Rock comes with two dip switches which can be set on or off. On being for 4-8 ohms and where it is currently set. I am struggling to understand the lack of volume although Roland Rock suggested that it does not get loud until after 12.00. I have tried that too but still relatively quiet. I have the gain set at 14.00hrs so just clipping. I think RR is relatively close to me so may PM him and take mine up to him for a side by side comparison. It will also tell me if my cabs are not a good match.[/color]

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[quote name='Bobthedog' timestamp='1459333869' post='3015485']
[color=#0000cd]I have tried the other way amp to cab to cab but will give it another go. Thank you. I am thinking of just one 4ohm cab as that will remove any confusion re ohms on my part![/color]
[/quote]

It shouldn't matter anyway to be honest - the amp's speaker outputs are wired in parallel and I imagine most cab's wiring is also in parallel.

It sounds like you've got the head set right (in 1000W@4 ohm/500W@8 ohm mode), so that eliminates the possibility that you're only getting 600W @ 4 ohms as per the other mode. I take it if you change mode it's even quieter?

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[quote name='neepheid' timestamp='1459337684' post='3015533']
It shouldn't matter anyway to be honest - the amp's speaker outputs are wired in parallel and I imagine most cab's wiring is also in parallel.

It sounds like you've got the head set right (in 1000W@4 ohm/500W@8 ohm mode), so that eliminates the possibility that you're only getting 600W @ 4 ohms as per the other mode. I take it if you change mode it's even quieter?
[/quote]

I have not tried changing the mode, but will look at that too. Thx. Currently now trying to sort out a bricked TCE Spectracomp that arrived this morning. :-( I though bass was supposed to be fun!

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If it helps, my 4ohm Blue Rock, which is connected to a 4ohm BF STwin is really loud. I usually play with gain around 2 o'clock, master around 11 o'clock and that's spot on with our drummer.
Also bear in mind that the master is logarithmic, so gets much louder the higher you go, all the way to max.

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[quote name='Roland Rock' timestamp='1459434047' post='3016552']
If it helps, my 4ohm Blue Rock, which is connected to a 4ohm BF STwin is really loud. I usually play with gain around 2 o'clock, master around 11 o'clock and that's spot on with our drummer.
Also bear in mind that the master is logarithmic, so gets much louder the higher you go, all the way to max.
[/quote]

Thank you. My gain is also around 2 o'clock; at 11 o'clock on the master I am just passed practice volume. Interestingly when I put my TC Spectracomp into the loop at around 25% comp the cab output level leaps up and the master needs bringing back down an "hour"

Perhaps it is just my fingers or I am more deaf than I thought. I will seek out a 4ohm single cab and see if that makes a difference.

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All the advice is already given above but one thing I would say is that you can't ever compare one amp's volume to another by where (comparatively) you have to turn the dials to! Trace were the classic example of this whereby BANG everything was loud in the first couple of clicks of input/output gain... but after 30-40% of travel you didn't 'really' get much more volume. Conversely, H&K's bassbase range of amps required a lot more input gain to get to where a Trace would be BUT it did get louder once you'd matched/set the input gain correctly.

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[quote name='warwickhunt' timestamp='1459447840' post='3016752']
All the advice is already given above but one thing I would say is that you can't ever compare one amp's volume to another by where (comparatively) you have to turn the dials to! Trace were the classic example of this whereby BANG everything was loud in the first couple of clicks of input/output gain... but after 30-40% of travel you didn't 'really' get much more volume. Conversely, H&K's bassbase range of amps required a lot more input gain to get to where a Trace would be BUT it did get louder once you'd matched/set the input gain correctly.
[/quote]

Fair comments, I do not think I am doing that, but my ears do run into trouble on the RH750 before 50% vol. I cannot get any near that threshold on the Glock even at two thirds volume in my 11x 10' music room/study. The fact that RR is gigging with the master at 45% vol suggests something is amis. Be it mismatched cabs or something else.

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[quote name='warwickhunt' timestamp='1459449737' post='3016789']
Your speaker leads aren't out of phase are they? They shouldn't be if they work fine as a pair with the TC but have you tried to swap backwards/forwards to check?
[/quote]

I don't think so and have just changed per Neephied's suggestion to head to cab to cab. It has made no difference to the sound but would perhaps address any phasing issues. Next step is to try a different cab / cabs and see what happens then.

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[quote name='Bobthedog' timestamp='1459452351' post='3016833']
I don't think so and have just changed per Neephied's suggestion to head to cab to cab. It has made no difference to the sound but would perhaps address any phasing issues. Next step is to try a different cab / cabs and see what happens then.
[/quote]

'If' your leads are wired out of phase, switching how you plug the cabs in would make no difference. The phase issue can be discounted if you used the same leads with the same cabs when you were using the TC amp.

[b]"[/b][color=#282828][font=helvetica, arial, sans-serif][b]do I need to buy some 4ohm cabs? Am i only getting 250 watts from each cab due to them being 8ohm cabs?"[/b] - The difference between getting a few more 100w out of your amp using different cabs is a LOT smaller than you imagine. A generalisation is that to get double the volume, you'd need TEN times the watts... to be twice as loud as 100w you need to be using 1000w! However, stuff like cab sensitivity etc plays a lot bigger part. I think you've nailed that you just need to establish if your Glock is duff! ;)[/font][/color]

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[quote name='tauzero' timestamp='1459498537' post='3017065']
Have you got a "pad" or active/passive switch on it? If so, switch the pad off and/or the active/passive to passive.
[/quote]

'tis a separate input on the Glock but thank you.

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[quote name='warwickhunt' timestamp='1459499671' post='3017081']


'If' your leads are wired out of phase, switching how you plug the cabs in would make no difference. The phase issue can be discounted if you used the same leads with the same cabs when you were using the TC amp.

[b]"[/b][color=#282828][font=helvetica, arial, sans-serif][b]do I need to buy some 4ohm cabs? Am i only getting 250 watts from each cab due to them being 8ohm cabs?"[/b] - The difference between getting a few more 100w out of your amp using different cabs is a LOT smaller than you imagine. A generalisation is that to get double the volume, you'd need TEN times the watts... to be twice as loud as 100w you need to be using 1000w! However, stuff like cab sensitivity etc plays a lot bigger part. I think you've nailed that you just need to establish if your Glock is duff! ;)[/font][/color]
[/quote]

Yup, same cables and good point re the power difference. It still boils down to this being a relative test as opposed to outright volume. I will take the Glock out at the weekend and try some different cabs.

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  • 4 months later...

[quote name='Musashimonkey' timestamp='1471471741' post='3113356']
How did it go? Have you managed to solve the issue?
[/quote]

I have, although I am not sure how and thank you for asking.

I suspect it is down to finger strength as my volume has increased for no discernible reason other than practicing harder until it became the norm. I still have tone control within my fingers, but I seem to be playing naturally harder. The change to a 4ohm Barefaced Big Twin 2 may also have helped.

At 09:00 hrs on the volume dial my neighbors some 60 yards away can apparently hear me at night. My gain is now dialled down to 01:00hrs.

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