Post by Michael Bartee on Nov 17, 2007 17:09:24 GMT -7
A while Back I was shopping around for an attenuator to use with my new Carmen Ghia combo and was never satisfied with the information I could find to get a feel for how they would interact with the amp. Now that I own the Mini-Mass I thought I would pass along some data that might be of use to anyone looking at attenuators.
I have the 50 watt Weber Mini-Mass in use with my Carmen Ghia 1x12 combo with a Celestion Vintage 30 speaker.
The measurements were taken as follows.
The amplifier (Dr. Z Carmen Ghia) was sitting on the floor across a corner of the room with each back corner of the amp 3" out from the wall, the amps center was 14" out from the corner of the room).
The SPL meter was set for "C" weighting and fast response time and centered left to right with the speaker/amp, 3' from the face of the amplifier, and 25" above the floor mounted on a tri-pod (the floor is carpet covered).
A continuous open "A" chord (very fast repeated strum to create a constant level) played on the bridge pickup of my Gibson '59' RI was used for all test. The volume was set WAO (full up), tone set to 12:00.
Test Results.
No attenuator in line = 112dB.
Mini-Mass full CW in "BYPASS" = 112dB (no insertion loss in "Bypass")
Mini-Mass full CW = 106 dB (6dB of attenuation/insertion loss).
Mini-Mass @ 3:00 = 104dB.
Mini-Mass @ 12:00 = 101dB.
Mini-Mass @9:00 = 98 dB.
Mini-Mass @ minimum FCCW = 72dB.
There is a lot of change between the 9:00 position and FCCW.
In the future I will do some sound clips to illustrate the tone differences, or should I say lack of tone difference the attenuator creates.
My final conclusion is that the Weber Mini-Mass does a great job of dropping the SPL level of the amp and does NOT harm the original tone of the Carmen Ghia. Maybe this is due to the quality of the Ghia's transformers and how they respond to the load that the Mini-Mass presents. Maybe it's due to the quality of the Mini-Mass design (mechanical load verses pure resistive). Or possibly the combination of both.
When I eventually purchase an Air Brake, I will do the same test and pass that information along as well.
I hope this is useful.
I have the 50 watt Weber Mini-Mass in use with my Carmen Ghia 1x12 combo with a Celestion Vintage 30 speaker.
The measurements were taken as follows.
The amplifier (Dr. Z Carmen Ghia) was sitting on the floor across a corner of the room with each back corner of the amp 3" out from the wall, the amps center was 14" out from the corner of the room).
The SPL meter was set for "C" weighting and fast response time and centered left to right with the speaker/amp, 3' from the face of the amplifier, and 25" above the floor mounted on a tri-pod (the floor is carpet covered).
A continuous open "A" chord (very fast repeated strum to create a constant level) played on the bridge pickup of my Gibson '59' RI was used for all test. The volume was set WAO (full up), tone set to 12:00.
Test Results.
No attenuator in line = 112dB.
Mini-Mass full CW in "BYPASS" = 112dB (no insertion loss in "Bypass")
Mini-Mass full CW = 106 dB (6dB of attenuation/insertion loss).
Mini-Mass @ 3:00 = 104dB.
Mini-Mass @ 12:00 = 101dB.
Mini-Mass @9:00 = 98 dB.
Mini-Mass @ minimum FCCW = 72dB.
There is a lot of change between the 9:00 position and FCCW.
In the future I will do some sound clips to illustrate the tone differences, or should I say lack of tone difference the attenuator creates.
My final conclusion is that the Weber Mini-Mass does a great job of dropping the SPL level of the amp and does NOT harm the original tone of the Carmen Ghia. Maybe this is due to the quality of the Ghia's transformers and how they respond to the load that the Mini-Mass presents. Maybe it's due to the quality of the Mini-Mass design (mechanical load verses pure resistive). Or possibly the combination of both.
When I eventually purchase an Air Brake, I will do the same test and pass that information along as well.
I hope this is useful.