• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Heck with this "class D" crap

#41
nashvillebill said:
low mains voltage can cause those amps to go into premature protection mode.
Click to expand...

I've played many clubs where the voltage drops when the house aircon kicks in, the fridges all kick in and/or something similar... This will effect all amps that draw a fixed voltage/wattage all the time (solid state and/or digital - i.e. my former Eden WT 400 and 550 amps). Tube amps typically only draw what they need, when they need it... All others draw double to triple what they need, all the time.

House/city power drops have miserable results on all electronics! I've even installed a transformer and voltage rectifier for my house, here in So Cal, to prevent ruining my electrical devices (fridge, oven, a/c, etc).

Though I too prefer tube amps, "my sound" only happens when a certain volume is met with a tube amp (almost never happens in smaller clubs!). Whereas, my RH450 sounds and feels like it's at *that* point all the time...

Your solution is to use a power supply that can deal with voltage drops and consistently deliver the necessary voltage/wattage, not replacing the amp!
 
#43
ScottTunes said:
I've played many clubs where the voltage drops when the house aircon kicks in, the fridges all kick in and/or something similar... This will effect all amps that draw a fixed voltage/wattage all the time (solid state and/or digital - i.e. my former Eden WT 400 and 550 amps). Tube amps typically only draw what they need, when they need it... All others draw double to triple what they need, all the time.
Click to expand...

How very odd...... and wrong.

Tube class AB amps draw the most on idle, typically, of the amps that are likely to be used for MI. Tube heaters, and bias current in the output.
With signal, they are perhaps 40% to 60% efficient in general.
So they draw a fairly high "base load", and draw more at higher output levels

SS class AB would be next, no heaters, but a bit of bias current at idle. Also around 50% to 70% efficient with signal. So they draw a smaller "base load" plus more as output increases.

Class-D typically draws the least.... under ALL conditions..... Rather low idle current/power, and typical efficiency from 70% to 90% when producing output. Typically quite a small base load, plus almost a watt-for-watt increase as output power goes up.
 
#44
I may be "wrong" (as in incorrect) about the technical details... But I am not "wrong" that my SS amps would NOT perform during a club's "brown-outs," and my tube heads would... The Edens, for example, would crap out... NOT producing an intelligible sound. So please explain the technical aspects... But that is my experience. Our Mackie (solid state) PA had the same issues, at the same time (never tried a tube PA)...

PLEASE EXPLAIN
 
#48
ScottTunes said:
I may be "wrong" (as in incorrect) about the technical details... But I am not "wrong" that my SS amps would NOT perform during a club's "brown-outs," and my tube heads would... The Edens, for example, would crap out... NOT producing an intelligible sound. So please explain the technical aspects... But that is my experience. Our Mackie (solid state) PA had the same issues, at the same time (never tried a tube PA)...

PLEASE EXPLAIN
Click to expand...

The reason is that some amps have a built-in shutdown feature that kicks in if the mains voltage drops below a threshold such as 90 or 100 V. This is a case of good engineering practice conflicting with real world operating conditions.

Amps with switchmode power supplies draw more current as the mains voltage drops, so the designer has to choose a threshold based on the safe operating area of critical components, such as the switching transistors. Some Class-AB amps probably had brownout protection circuits as well.

I remember playing a gig where the venue accidentally plugged us into an outlet that was on a light dimmer. When it was time for us to play, they dimmed the lights, and the singer's PA shut down. We never guessed what was going on until after the gig, but we got through it by using my bass amp as a power amp for the PA, and me playing my upright unplugged. Both amps were Class-AB with conventional power supplies.
 
#49
I have tube, SS, and Class D amps and have used them all a lot. My $.02...

I really like the new GB heads!There was only one gig where my GB Shuttle MAX 6.0 every sounded crappy due to low power which was on a generator. The voltage dropped so low that the keyboardists's rig was changing patches at random. The bass amp was fuzzing in and out. What a bummer. I had the same thing happen with an SWR SM-400 and it was grim as well, but not nearly so grim. My rack rig with the Crown PSA2 does not sound very different at all when the power is low. The caps in that thing are bigger than beer cans! Last but not least the Trace V6 sounds better with good power I think, but has never fuzzed in and out due to power. Power tubes, well that is another story.
 
#53
Sounds like a BBA problem……. (Between bass and amp) I play out with a DB750 but I need an amp that will sound great and perform for an owner who isn’t a good amp owner. I push it too hard sometimes I have too much bass in the EQ and stress the amp and do so many stupid things that would shut down a “class D” amp. It wouldn’t be the D amp fault it would be mine.

All great solutions and suggestions from everyone already. For me the tube and hybrid heads and big heavy Mesa cabs work for me because they sound and perform incredibly well even though when it comes down to it I really abuse the stuff way more than I should and they are forgiving as all get out.

Taste of tone is another story. I have played through good set ups and rigs that were driven by various class D heads and I have always preferred the big heavy amps. Maybe it’s all in my head but I don’t feel the huge transient punch and power and creamy thick low end to me through the D stuff at the volumes I prefer to play at but I hope it gets there because carrying my rig into a place isn’t too bad but man at 2 AM it’s a freaking nightmare! I will say that Aguilar TH500 is pretty much the answer to the class D amps don’t have guts comments I just wish there was an Aguilar TH1000 I would be all over it.
 
#54
Its interesting to me that for years it was 'toob vs. solid state' where tubes were awesome and solid state sucked or vice versa. People didn't classify which type of solid state, just any.

Then it became 'Class D vs Big Iron (or AB, or big transformer). Its the exact same debate, same stances.

I can't wait for people to catch on to the fact that light doesn't mean class D and that class D has been around for half a century...then we'll move on to the CLASS H SUCKS vs. Class D debate.
 
#56
New speaker cables, two 4x10s...maybe in these bars the power is suspect. 350 is SVT power, and to you guys tellin me to get tubes...tubes are all I've ever had.

I'm gonna start bringin my own power cords now too.

Love the PF stuff...and we're not THAT loud...
 
#58
Mike in Chicago said:
New speaker cables, two 4x10s...maybe in these bars the power is suspect. 350 is SVT power, and to you guys tellin me to get tubes...tubes are all I've ever had.

I'm gonna start bringin my own power cords now too.

Love the PF stuff...and we're not THAT loud...
Click to expand...
Check the ohmage on both cabs. Possibility one is mislabeled 8ohm and one could be 4ohm.
 
#60
ScottTunes said:
I may be "wrong" (as in incorrect) about the technical details... But I am not "wrong" that my SS amps would NOT perform during a club's "brown-outs," and my tube heads would... The Edens, for example, would crap out... NOT producing an intelligible sound. So please explain the technical aspects... But that is my experience. Our Mackie (solid state) PA had the same issues, at the same time (never tried a tube PA)...

PLEASE EXPLAIN
Click to expand...

As mentioned, undervoltage cutout, and/or circuit features that *act* as an undervoltage cutout, even if their actual function is not for that.

What you are seeing is that MOST tube amps are very simple devices, and that as a result, most will work to at least some degree until the heater voltage is too low and the tube cathodes stop emitting electrons.

The bias may go completely wonky, and power may drop, but generally a tube amp will stay "on" until a voltage lower than you are probably interested in.

There are exceptions....... An SVT-VR without having the relay bypassed will often cut out at a very normal voltage like 110 volts... Just a bit of over-complication in the amp that actually has a different purpose (ensuring that the high voltage is off for a while after turn-on even if "standby" is set to the "playing" position).

SS amps have voltage regulators etc, and their more complicated innards have minimum voltage requirements. The lightweight amps have "switching power supplies" (SMPS) and those, as mentioned, will cut out at low voltage, usually somewhere between about 80 and 105 volts.

It has virtually nothing to do with "power draw at idle".
 

Latest posts

Top Bottom
Back