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Mesa Subway D-800+

#382
McFarlin said:
How does the deep switch interact with the new hpf control?
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The deep switch will always shift the effective HPF down a few Hz. The same thing will happen with the bass eq, it's part of how filter response is defined or specified. This is true of all amps, not just ours of course. This is why the variable HPF can be a useful tool for tuning the overall low end response.
 
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#384
Jeff Bonny said:
When you put one HPF in front of another is it simply a matter of the higher frequency roll-off taking the lower one out of play or can there be more going on? I'm thinking the small Broughton and FDeck boxes that are so popular around here in front of this amp.
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Same question! I'm thinking if you set the pedal above 30hz (where the D800's HPF filter is) it would of course start rolling off where the pedal is set, but because of the filter in the amp the slope would be much steeper. I'm just guessing.
 
#387
Jeff Bonny said:
When you put one HPF in front of another is it simply a matter of the higher frequency roll-off taking the lower one out of play or can there be more going on? I'm thinking the small Broughton and FDeck boxes that are so popular around here in front of this amp.
Click to expand...
There are a couple of reasons why cascading two second order filters is the best of all worlds (IMO) but because there are 2 DIFFERENT things being affected by the same filter set.

With the control all the way to the left, it's a classic 4th order filter which operates at 30Hz and at the control is rotated clockwise up to 40Hz at which point the filter set begins to operate as 2 independent but related filters, the first variable filter has a second order response and works better for tuning of low end response. So for say the adjustable HPF being set at 70Hz, it looks like a classic second order filter (a cross between a BW and SK alignment) and as the audio program material drops down to around 40Hz, begins the transition from second order to 4th order for driver protection purposes. This transition point varies based on the variable filter's knee frequency. It kills several birds with one well placed stone, and is a circuit that I have used for many years in both bass guitar as well as pro audio.

The problem with using a single variable forth order filter is that the transition is just too steep and does not sound very musical as well as feels awfully abrupt to most players. This is the case of more not being better ;)
 
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#393
score........
20161024_185737.jpg

RoadRanger said:
Don't care what you call it as long as it has that "missing" variable LPF on the DI ;) .
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if you are worried about high end hiss I can tell you this,...one of the things I like to do when I check out a new amp (as I did today) is to crank up all the bass and treble controls well beyond useable levels and see if I get any hum or hiss, the 800+ didn't make a peep, his or buzz
 
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#396
I want Mesa to make their version of the Demeter 800w old-skool-lookin' bass head. Without a gaudy logo blocking the view of the glowing tubes.

Mesa 800 Double-Plus Good.

Please?

VTBP-M-800D

Seen it for the 1st time just yesterday. Classic, cool and crushing in any easy carry. Gotta have all 4 C's.
 
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