dave74
Well-known member
My Tremoverb and Multi-Watt have them. Many of their amps do not though. My single does not, and the early 2-channels don't either.Mesa doesn't even believe in 16 ohm outputs, and that's what most of my cabs are
Dan Gleesak
Well-known member
Most of their manuals tell you straight out to mismatch the loads and see if you like it. I like that lolMesa doesn't even believe in 16 ohm outputs, and that's what most of my cabs are
eclecticsynergy
Well-known member
I've always followed conventional wisdom:
4Ω output into 4Ω or 8Ω load
8Ω output into 8Ω or 16Ω load
16Ω output into 16Ω load only
and never running amps into a lower impedance than they want to see
Never had a problem doing it that way. I do feel that Boogies traditionally are more tolerant of mismatches than Marshalls.
I've seen plenty of blown Marshalls and I don't recall ever seeing a blown Boogie - certainly none of mine ever went.
In the 70s when Randy Smith was building me my first one (an early Mk II) he told me it could handle any impedance mismatch.
As mentioned above, he said 'try anything and find what you like best.'
Most of the time (except in the studio) I was pushing an old Marshall 4x12 cab (a 15Ω load) from the 8Ω output.
I played more than three thousand sets & sessions on that amp before I finally retired it from active duty.
In all that time it only needed one resistor replaced. The thing's bulletproof and has a huge output transformer.
As for flyback voltage, I think that might only be a cause for concern when running an amp dimed into a higher load than spec'd.
At today's stage volumes nobody really runs flat out anymore, except maybe for arena stages.
Or into an attenuator, but modern load boxes generally have options to match their impedance with your head.
I guess pushing a 16Ω load hard from a 4Ω output might be more concerning. If I ever did that, it wasn't a long-term configuration.
4Ω output into 4Ω or 8Ω load
8Ω output into 8Ω or 16Ω load
16Ω output into 16Ω load only
and never running amps into a lower impedance than they want to see
Never had a problem doing it that way. I do feel that Boogies traditionally are more tolerant of mismatches than Marshalls.
I've seen plenty of blown Marshalls and I don't recall ever seeing a blown Boogie - certainly none of mine ever went.
In the 70s when Randy Smith was building me my first one (an early Mk II) he told me it could handle any impedance mismatch.
As mentioned above, he said 'try anything and find what you like best.'
Most of the time (except in the studio) I was pushing an old Marshall 4x12 cab (a 15Ω load) from the 8Ω output.
I played more than three thousand sets & sessions on that amp before I finally retired it from active duty.
In all that time it only needed one resistor replaced. The thing's bulletproof and has a huge output transformer.
As for flyback voltage, I think that might only be a cause for concern when running an amp dimed into a higher load than spec'd.
At today's stage volumes nobody really runs flat out anymore, except maybe for arena stages.
Or into an attenuator, but modern load boxes generally have options to match their impedance with your head.
I guess pushing a 16Ω load hard from a 4Ω output might be more concerning. If I ever did that, it wasn't a long-term configuration.
Greazygeo
Well-known member
When I got my first Marshall (72 50 watt 1987) in 85 had a sound city cab with nothing marked on it. No clue about anything so I just tried the imp selector in the three positions and left it where it sounded best. Got more amps as time went on and always used that same setting. Yeah it was 8 ohm on amp with a 16 ohm cabinet…now I am lazy and just match em up. Not that big a difference to worry about.
RedB4Black
Well-known member
KHE has an impedance guide….
https://static1.squarespace.com/sta...f1a555a5e66/1665937225046/Impedance+Guide.pdf
using mine I typically play 2 16 ohm cabs so all my amps are set at 8 ohms. if I. Only going to use one cab, I typically go back and switch the amps to 16 ohms. I will say I’ve never had any problems though just keeping on 8 ohms with only one 16 ohm cab or vice versa as I sometimes forget to switch the cable.
midnightlaundry
Well-known member
The argument is why you blew your shit up.. LOL
But years ago, I had 1-8 ohm and 1-16 ohm Cab into my old Mesa 290 Power Amp that only had 4 and 8 ohm jacks and it never blew..
The Cabs had the same speakers but they did sound different. I think the 16 sounded darker.
But years ago, I had 1-8 ohm and 1-16 ohm Cab into my old Mesa 290 Power Amp that only had 4 and 8 ohm jacks and it never blew..
The Cabs had the same speakers but they did sound different. I think the 16 sounded darker.
H
harddriver
Well-known member
Running a Marshall set to 8 ohms into a 16 ohm load is a safe mismatch as well a an amp set to 4 ohms into an 8 ohm load. It actually takes some stress off the output transformer according to some amp gurus and does not affect tube life to my knowledge... but I am sure there are some detractors somewhere. I have been running my marshalls set to 8 ohms into 16 ohm cabinets for years with absolutely no issues whatsoever.
As others have said, you would not have damaged your amp doing so.
What you should NEVER do is set the amp to 16 ohms and run an 8 ohm cabinet. THIS IS AN UNSAFE mismatch.
AND NEVER go more than a 100% mismatch. Amp set to 8 into a 16 load is safe....Amp set to 4 ohms into a 16 ohm load is UNSAFE.
As others have said, you would not have damaged your amp doing so.
What you should NEVER do is set the amp to 16 ohms and run an 8 ohm cabinet. THIS IS AN UNSAFE mismatch.
AND NEVER go more than a 100% mismatch. Amp set to 8 into a 16 load is safe....Amp set to 4 ohms into a 16 ohm load is UNSAFE.
Last edited:
midnightlaundry
Well-known member
Timely Thread..
Almost blew my shit up.. Did some tweaking and reconnected everything.. Cranked it up into the Attenuator and the sound was muffled and fuzzy. I'm like WTF?
I was mismatched 16 ohms into an 8 ohm load.. Sounded like shit.. Matched the Impedance and got my sound back without letting the smoke out.. Lucky.
Almost blew my shit up.. Did some tweaking and reconnected everything.. Cranked it up into the Attenuator and the sound was muffled and fuzzy. I'm like WTF?
I was mismatched 16 ohms into an 8 ohm load.. Sounded like shit.. Matched the Impedance and got my sound back without letting the smoke out.. Lucky.
Bad Brain
Well-known member
I did the opposite, which everyone says is okay.
Dan Gleesak
Well-known member
I really comes down to the amp itself. 16ohm into an 8ohm cab will essentially cause a rise in current and a drop in voltage, i.e. more heat and more work for the tubes. Whether or not it does any harm depends on how robust the components are and how hard the amp is being run to begin with
rstites
Well-known member
Impedance matching is ideal as it provides the greatest power transfer. This means that when you dial in for a certain volume, it'll take the least effort from the amp to provide the necessary delivered powered to the speakers.
Solid state amps are always better off driving high impedance than lower impedance. (OK, someone give me an exception now that I said that! lol) Tube amps aren't so straight forward, so that driving a lower impedance speaker isn't automatically the worse choice. Regardless, I'd highly suggest staying within one selection of the cab impedance.
Remember: impedance isn't one set number and isn't a perfect number anyway. It varies with frequency and the actual capacitive vs. inductive reactance can vary within that. (You see this on speaker spec sheets, as well as output xfmr specs......and both vary with load.)
Solid state amps are always better off driving high impedance than lower impedance. (OK, someone give me an exception now that I said that! lol) Tube amps aren't so straight forward, so that driving a lower impedance speaker isn't automatically the worse choice. Regardless, I'd highly suggest staying within one selection of the cab impedance.
Remember: impedance isn't one set number and isn't a perfect number anyway. It varies with frequency and the actual capacitive vs. inductive reactance can vary within that. (You see this on speaker spec sheets, as well as output xfmr specs......and both vary with load.)
Bad Brain
Well-known member
For those inquiring about impedance mismatch with the Two-notes Captor, I found this: https://www.two-notes.com/en/knowledge-base/can-i-mismatch-the-impedance-of-the-amp-and-load-box/
Interestingly, "The impedance of the cabinet does not matter if the attenuator is engaged (Volume Level on LOW or halfway position). If the Volume Level switch is on FULL, the cabinet’s impedance is the impedance taken into account." and, "The attenuation levels will be modified when mismatching [box w/ cab], albeit slightly – around -6dB. Tonally there will be a difference, but since it also depends highly on the impedance curve of the speaker we can’t give you a general answer that applies to all cabs."
https://www.two-notes.com/en/knowle...mpedance-of-the-amp-and-load-box/#comment-893
Interestingly, "The impedance of the cabinet does not matter if the attenuator is engaged (Volume Level on LOW or halfway position). If the Volume Level switch is on FULL, the cabinet’s impedance is the impedance taken into account." and, "The attenuation levels will be modified when mismatching [box w/ cab], albeit slightly – around -6dB. Tonally there will be a difference, but since it also depends highly on the impedance curve of the speaker we can’t give you a general answer that applies to all cabs."
https://www.two-notes.com/en/knowle...mpedance-of-the-amp-and-load-box/#comment-893