Heck with this "class D" crap

[warwick.hoy]

No, no! It's gotta be a problem with the Class D amp. 'Cuz the OP said so!

That's the way it works around here, doncha know?

MM

FWIW,...I totally attribute my issues with my Class D to me not running it as efficiently as it could be. I kinda impedanced myself into a corner when I ignorantly bought a 4ohm 4x10. Should have gotten an 8ohm but I though twice the power was twice the volume.

I know better now. Had I been able to run my class D into two 4x10s,...it probably would have been a lot louder and less prone to fail safe even with my fuzz and effects use.

Running my SVT into two 4ohm cabs currently and I'm loving my tone.

 

[Mr. Foxen]

Do what I am about to do, build a way overspec'd tube power amp and buy a nice preamp.
Use the meatiest power transformers and rectifiers as you can to almost eliminate dropout, and an output transformer that is rated twice as high as you need it for. Put some (2-4) NOS RCA 807's in the middle and you have a (50-100) watt rig, that doesnt sound like much but GOSH DARNIT you will have all 100 watts.
(I can and have built preamps for bass it is a hassle though to find the right vintage parts, but then again ampeg does preamps well)

Much easier path is to score an old PA amp an uprate the power filtering, because the best of the iron from their heyday is better than what you get now, but capacitors now are so much better.

 

[popgadget]

I would suggest that the amps being Class D has nothing to do with your problem. Both my Shuttle and my Streamliner soldier on kicking ass week after week generally driving a 4ohm fEARful load. For me those Class D amps and cabs are the perfect solution, my SVT stuff all stays home, until it finds a new place to live.

 

[Bongofour]

+1!

What kind of music are you playing, how loud is the band, what speakers are you using, etc.? More information will go a long way to determining why you are having this issue.

My former Markbass F1 cut out a couple times at one gig but I determined that most likely the speaker cabinet I used for this gig has a very low point in it's impedance curve that went below the 4? minimum at the right frequency that triggered it. Interestingly, the signal from the DI still worked so I was still going through the PA, just not my cab. Turning the amp off and back on reset the limiter. The other micro amps I have have never cut out and get quite loud.

Most likely, you just need more of everything (power/speakers) to not push the amp beyond it's limits (no pun intended).

Just had my f500 sent in under warranty for the same issue
Supposedly it was fixed although I haven't taken it out since.

 

[Jeff Scott]

Bongofour, do you know what they did to cure the issue?

 

[JimWasHere]

I love this thread... All the solutions and opinions being offered, and the OP that never did actually ask a question

 

[Pilgrim]

He's welcome to proceed in ignorance of his alternatives.

You know the old saying "If the shoe fits, wear it?"

Some folks not only wear it, but take it off, wave it over their head and announce to everyone around them that they're wearing it.

 

[adivin]

He's welcome to proceed in ignorance of his alternatives.

You know the old saying "If the shoe fits, wear it?"

Some folks not only wear it, but take it off, wave it over their head and announce to everyone around them that they're wearing it.

Yea like hauling two 410s...

 

[Jerrold Tiers]

Yes, and some amplifiers have "punishment" protection modes, too....

I agree, dial back, reduce volume, whatever, but try your level best not to shut down..... in a performance situation, theat is the last and worst choice of protection modes..... eventually you might have to, but a little overdesign to avoid it is worth the price. Better a bit higher price than letting your users down.

Class-D IS the one case where overdrive is un-good for many amps.....and they may cut out, or shut down. There ARE ways around the issues, but not everyone uses them.

Then also, since class-D is "efficient" some don't use a big enough heatsink..... some of the first class-D were notorious for that. So then it is either blow up (they mostly did) or shut down due to overheating.

Most class-AB designers are quite aware of the heat issues, and deal competently with them.

 

[nashvillebill]

I have seen service bulletins on certain Class D amps advising that low mains voltage can cause those amps to go into premature protection mode. Dunno about this particular model, but it seems plausible.

A lot of folks don't realize the voltage drop that can occur in circuits when they are loaded close to the maximum current. The breaker won't trip, because the current does not exceed the breaker, but the supply voltage may drop significantly, especially when long undersized extension cords are used. A 20% voltage drop would be quite possible then and the supply voltage could drop from 125 volts at the circuit breaker to below 100 volts at the amplifier.

 

[jlepre]

TROLL

 

[Primakurtz]

Back in the 1980's, I had three Ford Rangers in a row.
They all had problems, so I completely gave up on automobiles.

 

[B-string]

Back in the 1980's, I had three Ford Rangers in a row.
They all had problems, so I completely gave up on automobiles.

You should have just given up on trucks only!

 

[f64]

Played out last night w the third in a series of PF350's cut twice, and had the limiter on all night.

I'm gonna go out and buy a big ass tube amp and a hand truck

+1. Been there, done that.

 

[MJ_Sotti]

Thanks to about 87% of you. I'll get the old Svt4x10s cleaned up and try them. Also I'll tryto get my own power source which is spmetimes hard to do.

 

[fdeck]

Many amps - SS and Tube will cut out when conditions aren't optimal.
But SS Amp protection circuits of totally "Cutting out" have got to go.
They should lower the power and flash a big LED to say "I'm lowering the power to prevent from cutting out" or "I'm turning on the limiter to keep from cutting out"
Cutting out is just not acceptable anymore. This problem can be solved.

Hear, hear!

 

[Baird6869]

I found that larger hybrids solve the cutting out problem. My F1 into a 4ohm 4x10 would cut out every once in a while when I really pushed it.... My GK Fusion 550, GB 12.0 and Mesa M9 do not have this problem IME.

An 85lb all tube head is not always the only solution.

 

[Bongofour]

Bongofour, do you know what they did to cure the issue?

They had replaced two capacitors according to the return ticket
Although it may have had something to do with my Schroeder pl 1212 and ohm load
Nonetheless.... Love the head, love the cab

 

[lazyone2]

I have been pushing 2 wizzies at 2ohms with my Iamp Micro 550 for about 3 years no problems. Try reducing some of the lower bass frequencies, you know the ones you don't really hear.

 

[nysbob]

An 85lb all tube head is not always the only solution.

Maybe not, but it's a reasonable alternative.