Just wondering what you all prefer when running your Rocket amps. I just re-set my 4x12 cab to a 4ohm config and it seems just fine. I was running it on two of the speakers at 8 ohms for a while and that seemed a little looser and less focused. Is taking the rig to 16 ohms in series/parallel the better set up?
Ange
PS speakers are Celestion G-85s ( 3 of them ) and 1 warehouse 12-65
I know ... I have to bust loose for some better speakers at some point. Its a left over Peavey cab from my kids.
Rocket at 4, 8 or 16 ohms
Moderators: pompeiisneaks, Colossal
Re: Rocket at 4, 8 or 16 ohms
I haven't experiemented with different impedances as my cabs are all set to 16 ohms. But, in the past when I have had other options, I have never really heard that much difference.
On the other hand, I've read that ising the highest impendance setting on your transformer has some advantages, in that the whole winding gets used, rather than half, or less for the lower impendance taps.
One other thing to consider, is that series is a more dangerous arrangement than parallel, in that if one speaker goes out, the entire load is disconnected from your amp (no sound, effectively, no speakers), and your amp now sees no load, and as we know, that is a bad situation. Two series pairs in parallel, or pure parallel are safer because if one speaker goes, the rest will still work (although the impedance will no longer match).
On the other hand, I've read that ising the highest impendance setting on your transformer has some advantages, in that the whole winding gets used, rather than half, or less for the lower impendance taps.
One other thing to consider, is that series is a more dangerous arrangement than parallel, in that if one speaker goes out, the entire load is disconnected from your amp (no sound, effectively, no speakers), and your amp now sees no load, and as we know, that is a bad situation. Two series pairs in parallel, or pure parallel are safer because if one speaker goes, the rest will still work (although the impedance will no longer match).
Last edited by sliberty on Sun Jan 16, 2011 3:10 pm, edited 1 time in total.
Re: Rocket at 4, 8 or 16 ohms
This I have done just because I have different cabs I like to try all my amps through and they are all different impedance.
Run most of my amps at 4 ohms using a pair of 8 ohm speakers in 212 open back cabinets. This would include the Rocket and Liverpool.
The Express runs at 8 ohm load into a 412 cab. My Asteroid/K60 is also run through this 412 cabinet.
My friend likes my Rocket Reverb into the 16 ohm closed back verticle slant 212 with Scum Backs. But I prefer this amp with the 4 ohm 212 openback with Vin 30.
I don't think we all have enough money or space to conduct a good test of what works and doesn't
Mark
Run most of my amps at 4 ohms using a pair of 8 ohm speakers in 212 open back cabinets. This would include the Rocket and Liverpool.
The Express runs at 8 ohm load into a 412 cab. My Asteroid/K60 is also run through this 412 cabinet.
My friend likes my Rocket Reverb into the 16 ohm closed back verticle slant 212 with Scum Backs. But I prefer this amp with the 4 ohm 212 openback with Vin 30.
I don't think we all have enough money or space to conduct a good test of what works and doesn't
Mark
Re: Rocket at 4, 8 or 16 ohms
Is your question trying to ask whether it is best to run cabinets that are matched to the output impedance or if it is better with a purposeful mismatch?angelodp wrote:Just wondering what you all prefer when running your Rocket amps. I just re-set my 4x12 cab to a 4ohm config and it seems just fine. I was running it on two of the speakers at 8 ohms for a while and that seemed a little looser and less focused. Is taking the rig to 16 ohms in series/parallel the better set up?
Ange
matching
Zippy, as the Rocket has the variable impedance switch, I am interested in the varying responses within a matched framework.
So Mark, what is about that variable that you prefer if you can describe the sonic differences. I know that this is all quite subjective.
Sliberty, yes I understand that safety element in going parallel, good thought. Would adding a DPDT switch in the rear to a 4 ohm setup ( 4x12 16 ohm speakers in parallel ) so that I only get two speakers in parallel for 8 ohms be a neat trick.
What did KF suggest as the prime selection for the the Rocket, in terms of speakers.
Lastly, is there any evidence that taking a 4x12 16 ohm enclosed cab to an open back relationship is useful.
So Mark, what is about that variable that you prefer if you can describe the sonic differences. I know that this is all quite subjective.
Sliberty, yes I understand that safety element in going parallel, good thought. Would adding a DPDT switch in the rear to a 4 ohm setup ( 4x12 16 ohm speakers in parallel ) so that I only get two speakers in parallel for 8 ohms be a neat trick.
What did KF suggest as the prime selection for the the Rocket, in terms of speakers.
Lastly, is there any evidence that taking a 4x12 16 ohm enclosed cab to an open back relationship is useful.
Re: Rocket at 4, 8 or 16 ohms
Mine isn't testing in the correct sense, it's called noodling 
After I build an amp there is a lot of noodling to hear the amp after setting bias or trying many different tube combinations, speakers cabs and type of guitars tele, strat and LP.
Playing clean for awhile, then more crunch and finally wailing through high volume for awhile. After all that fiddle farting around, it usually boils down to one particular cabinet or speaker I like.
It amazes me that people can articulate the sound or tone they hear. To me there is bass, mid and treble. Then there is touch response, note articulation (clean notes), chord voicing, fast response (power section being stiff or is it softer), and all the other fancy things people say.
I have a hard time telling people what I hear and the next guy may not like what I like.
Mark
After I build an amp there is a lot of noodling to hear the amp after setting bias or trying many different tube combinations, speakers cabs and type of guitars tele, strat and LP.
Playing clean for awhile, then more crunch and finally wailing through high volume for awhile. After all that fiddle farting around, it usually boils down to one particular cabinet or speaker I like.
It amazes me that people can articulate the sound or tone they hear. To me there is bass, mid and treble. Then there is touch response, note articulation (clean notes), chord voicing, fast response (power section being stiff or is it softer), and all the other fancy things people say.
I have a hard time telling people what I hear and the next guy may not like what I like.
Mark
Re: Rocket at 4, 8 or 16 ohms
So this is as much about having different types of speakers into different numbers of speakers set into cabinets of varying configurations...M Fowler wrote:This I have done just because I have different cabs I like to try all my amps through and they are all different impedance.
Run most of my amps at 4 ohms using a pair of 8 ohm speakers in 212 open back cabinets. This would include the Rocket and Liverpool.
The Express runs at 8 ohm load into a 412 cab. My Asteroid/K60 is also run through this 412 cabinet.
My friend likes my Rocket Reverb into the 16 ohm closed back verticle slant 212 with Scum Backs. But I prefer this amp with the 4 ohm 212 openback with Vin 30.
If using the same speakers in the same cabinet, the effect of whether the speaker coils are 4/8/16 ohms (given the same total impedance) is going to be minimal (as Steve has already attested).
You can however, intentionally mismatch OT and total speaker impedance for a more perceptible - yet still safe - effect.
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Re: Rocket at 4, 8 or 16 ohms
Speaker changes are the most expensive tonal variations you can buy. Opening a 4x12 cabinet is a mess. No focus. Sounds like hell! Some types have a post from the front to back that is a dampener, tuning out extreme low flapping.
Mismatching the rig by 100% either way (8 into a 16, 16 into an 8 and so on) sounds different. It's safe, it sounds different.
When you disable a pair, it's not the imp change that makes the big difference, it's the 2x power, and how many inches are displacing air.
Mismatching the rig by 100% either way (8 into a 16, 16 into an 8 and so on) sounds different. It's safe, it sounds different.
When you disable a pair, it's not the imp change that makes the big difference, it's the 2x power, and how many inches are displacing air.
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.