an absolutelly pass labs off topic

[sakis]

before someone remove this post to solid state may also bother to read it first .....

lets see ... on scope there is an amplifier called BEHRINGER EP2500
more than 50 volts are produced in the out of this amp that is a big number i think so i will consider it as a pro amp.... ( copy of qsc rmx something)

this amplifier is ...
class H ( with the known goods and bads )
sziklai ( with the known goods and bads )
capacitor coupled ( with the known goods and bads )
featuring VI limmiter and electronic input limmiter also ( with the known goods and bads )


now i can hear a lots of things about how good this amp sounds and I also have my personal opinion but there is something that i will not "accept" any argument and that will be that the amplifier is virtually impossiblle to destroy

that is for a number of reasons
capacitors
sziklai
class H
transitors directly mounted on heatsink
limmiters
and crowbar


now from a safety aspect it seems that originally QSC people sit down and think how many available protections exist and apply them all ...now that is realy inovative cause the amplifier is solid rock but doesnt sound that perfect and to my understanding that is very correct marketing wise

there need for the one or the other

now the question is very simple

i wonder if the one and only Mr Pass had a target to produce one amplifier of the range of 250W made for medium Pa use ( all features included = both quality and safety ) while preserving average low cost and simple to make ...

I wonder how inovative this could be

[Nelson Pass]

Let's see... The goal is to produce a functional 250 watt amplifier
that is reliable, simple and doesn't cost much. It doesn't have to
have high end performance.

Yeah, I could do that.

[sakis]

good NP eventhough this is the pass labs off topic ( and all the pass people will hate me for that )
Given as fact the way you work your amplifiers a design like that will be an inovative joy
i hope that some time you are going to come back with a schematic ...

thanks NP

[tinitus]

Originally Posted by sakis

( and all the pass people will hate me for that )

Absolutely not, we would just grow into an even bigger fan crowd

[BobEllis]

I could almost hear Mr. Pass yawning at the "challenge" from across the continent. Why don't we take a look at what it might take to get to the target with some of his existing designs and add superior sound quality to the design requirements?

some options:

Super A-75. Bump the rails up to around 90V on the outputs (12+ pairs), 95-100 on the front end. Watch dissipation in various front end components. Maybe add cascodes to the front end to keep the input get dissipation down and current up, or use IRF510/9510. Do we want to add VI limiting or just throw a 10A slow blow on the output?

Bridged A-75, pretty darned rugged, but we might want to add protection.

AX100 bumped up to 60V rails and maybe protection circuits added

Any of these options may have to be thermally compensated if operated at lower than usual (for NP designs) bias. I mounted the Vgs multiplier on an output FET of my A-75s and it seems way overcompensated. It takes 45 seconds to come up to the point where it makes sound, and another minute or so bring the bias up to a decent no audible crossover distortion level. Probably not acceptable for PA use

Anyone else want to take a stab at it?

[Zen Mod]

why should we ?

Papa will bring that on back of the napkin ..... certainly it will need more efforts in presenting schematic in electronic format , than constructing it ..... at least for him

[Cal Weldon]

Originally Posted by sakis

I wonder how inovative this could be

Sounds more like an insult to me. IMHO if Mr Pass were interested in that part of the market, I believe Mr Pass would already be there. Are you talking about dumbing down one of his products?

[Steve Dunlap]

I believe any of the high powered Adcom amps he designed would work. Just add protection circuit and fan cooling.

[sakis]

CAL .... by all means i have no insult intention .... often forum members miss the point .... in real life there is need for both ...small 50 w class A designs that actually rock .... or more power amplifiers like 250W that dont really need to be of a bandwidth of 200 khz and so on and on

i will not be the one to say which one is better but for sure there is need and use for both ...

the all question is about unic designs ( any way you slice it the QSC was unic ) no matter if good better or best

The question was posted cause i think that if NP thinks of designing something like that it will be trully inovative ( and from many aspects )

Steeve..... ADCOMS will not make it ....they may as well serve the creteria of power and quality but will not survive if abused ....

the question is yet again between the balance of protection methods and quality of sound while keeping the machine low cost and simple to make
there inovation is needed ....
other than that copies of designs of how an Adcom is working you may find a gozzilion

i expect if Np ever bothers with that it will be something magic not an updated version of a 555II

[tinitus]

Originally Posted by Cal Weldon

Sounds more like an insult to me.

Absolutely not Cal
Have you been sleepy and tired

Lets look at what was said

"I wonder how innovative this could be"

To be insulting it should be like...."how innovative would that be"
Alone the use of "could" instead of "would" is a significant difference

The only insult might be the word "I wonder"
Besides, Nelson reponded positively


But innovative ?
Hmm...I wouldnt be surpriced if it would be a perfectly adjusted bootstrap design
But it would certainly be innovative to have such design in our treasure box

Well, a long time ago I remember Nelson saying .."I dont do AB, I leave that to others"
And that could only mean his trusted ingeneers, right ?

Yeah, sometimes i remember what noone else barely notice