That explains everything. Fancy "classe" A 😎 😎
The other circuit on the board I also simulated , and IT is just a glorified bias control for the output amps with a opto-isolator
that is "fed " by the CPU. (computer bias)
lacking the real CPU , just emulated min. to max on the
bias circuit , and viola !, the amp biased between 1 and
3amps.
The true voltage stage of the genesis must be on the
input board , that is why they use a 40-0-40v toroid for IT.
The main amp board is only for current amplification and
bias control.
No more mystery.. 🙂
OS
The other circuit on the board I also simulated , and IT is just a glorified bias control for the output amps with a opto-isolator
that is "fed " by the CPU. (computer bias)
lacking the real CPU , just emulated min. to max on the
bias circuit , and viola !, the amp biased between 1 and
3amps.
The true voltage stage of the genesis must be on the
input board , that is why they use a 40-0-40v toroid for IT.
The main amp board is only for current amplification and
bias control.
No more mystery.. 🙂
OS
I try to understand all that technical jargon but I can't. 
I am strictly an end user. I am a good listener of the music. 😀 I'm ok with that though! 🙂
The amp is a class A amp then? A few people said it wasn't a "true" class A... whatever that means. 😕
I am strictly an end user. I am a good listener of the music. 😀 I'm ok with that though! 🙂
The amp is a class A amp then? A few people said it wasn't a "true" class A... whatever that means. 😕
It definitely is class A , ...with a high output level , I suspect
that the CPU increases the biasing to keep the amp
properly biased in class A , but at idle , or if over-ridden by the
operator the amp might "back off" the current to minimize thermal
dissipation.
Being CPU based it might also go into a "idle state" to conserve
energy (and heat) when there is no output.
I don't have the CPU , so I can only guess at what it is
programmed to do.
OS
Ok, I gotcha now.
one thing I noticed when operating the "working" amp... it is supposed to hold in memory the bias and volume settings of the last time the amp was in use.
This one does not do that. Each time it is turned on, the bias is set to 20 and the volume is zero (their lowest settings).
I assume there's a small battery in the amp that's dead?
one thing I noticed when operating the "working" amp... it is supposed to hold in memory the bias and volume settings of the last time the amp was in use.
This one does not do that. Each time it is turned on, the bias is set to 20 and the volume is zero (their lowest settings).
I assume there's a small battery in the amp that's dead?
The stupid schema shows a cap (or battery) at the standby pin
of the CPU followed with the infamous (???) But it can be
assumed this is a lithium 3v cell or 1 farad (big)cap. Visual inspection would confirm this.
OS
pete did you see the brochure? there's a lot of info in there about how the amp operates. The transformers are 1.5KVA. I know we were talking about those today but weren't exactly sure of their specs.
http://www.genesisloudspeakers.com/archeology/genb200/stealthb200_brochure.pdf
http://www.genesisloudspeakers.com/archeology/genb200/stealthb200_brochure.pdf
From looking at the over-complexity of the circuits, all in the name of "digital control", I have a suggestion.
I see no reason why these could not be converted into stereo amplifiers only, discarding the input switching, readouts, remote control, bias adjustment, etc. If you liked the sound what you were listening to were the amplifier sections. Doing away with the digital control circuits and converting the output stages to fixed bias (maybe at 50% of the original "adjustable" range), along with either discarding or re-designing the protection method would likely result in a better sound than the original. It would also turn these into "normal" amplifiers that would be easier to service in the future.
Not that this would in any way be an easy modification, but it might be worth the investment.
Just my $0.02!
I see no reason why these could not be converted into stereo amplifiers only, discarding the input switching, readouts, remote control, bias adjustment, etc. If you liked the sound what you were listening to were the amplifier sections. Doing away with the digital control circuits and converting the output stages to fixed bias (maybe at 50% of the original "adjustable" range), along with either discarding or re-designing the protection method would likely result in a better sound than the original. It would also turn these into "normal" amplifiers that would be easier to service in the future.
Not that this would in any way be an easy modification, but it might be worth the investment.
Just my $0.02!
gungie, OS and I have talked about that option too. If the stock repairs aren't possible or feasible, we will go that route.
OS, when I was crating the amps I noticed that the amplifiers are not the same size. Weird! One amp is about 1/2 to 3/4 inch longer than the other. 😕
I was told that there was early and late versions of the amp. I didn't think the differences would be in the size of the chassis. I thought they'd be differences in the components used inside. Very strange.
Here's a couple pics of the top covers.
OS, when I was crating the amps I noticed that the amplifiers are not the same size. Weird! One amp is about 1/2 to 3/4 inch longer than the other. 😕
I was told that there was early and late versions of the amp. I didn't think the differences would be in the size of the chassis. I thought they'd be differences in the components used inside. Very strange.
Here's a couple pics of the top covers.
I see smudges..you weren't wearing your white gloves,
were you ? 🙂
If you look on the DIY photo thread...
http://www.diyaudio.com/forums/showthread.php?s=&threadid=96192&perpage=25&pagenumber=31
you will see where I communicated with the tasmanian
himself. He said his amps would love the genesis'spower supplies. His prices are a little "steep" , but for that
level of performance... worth it.
Still , I am pretty close to 100% sure the first amp will be
a sure bet to restore , but for mine (or your 3'rd one)
I will go (class AB). With 1 genesis in my livingroom I'm
sure I will have to turn on the AC , it is almost 80 here
(1-2kw heat)
.OS
OS I just saw that post. I think that would be the logical way to go with the 3rd amp. I'll have to wait for the sludge/rainy day fund to replenish itself first. 😀
Even though I could never see needing 500 wpc, would it be better to go with the 500watt amps versus the 300watt?
Sorry, but all 3 pairs of original white gloves were long gone by the time I got the amps. 🙄 You have my persmission to handle the amps without protective gloves! 😀
It's frickin 31 degrees here in NY!
😀Even though I could never see needing 500 wpc, would it be better to go with the 500watt amps versus the 300watt?
Sorry, but all 3 pairs of original white gloves were long gone by the time I got the amps. 🙄 You have my persmission to handle the amps without protective gloves! 😀
It's frickin 31 degrees here in NY!
Fixing your original stealth will be first priority , as the costs are already high. BUT , on the second one (or your 3'rd), I
was thinking... (see attached)
My FA2T in "beast mode" (mosfet ops)
same 300w , but $50-60 apiece.. 🙂
(see attachment)
Already have similar ones in my LR , very bulletproof , silent , loud.
genesis PS would be overkill. (just 1 trafo would do).
What is cool is that for 75$ I could do a 10 transistor
version..like this..
http://www.adam.com.au/cgpap/QuasiWeb/index.htm
(click on NMOS 300/500)
that is quasi's nmos 500.
So many choices.. make the boards , hook em' up
superamps (with that stealth PS, wow).
but this a future thought...
OS
Attachments
OS, I'm not sure if you're receiving my emails because you haven't responded.
The amps should arrive tomorrow or wednesday. The driver is supposed to call you 24 hours before he's due to arrive. Let me know how it works out.
thanks
The amps should arrive tomorrow or wednesday. The driver is supposed to call you 24 hours before he's due to arrive. Let me know how it works out.
thanks
I've beeen checking my email and have not seen you. I will
look out for the carrier's call tommorrow.
I have 2 crates and 2 4X4 beams to sit the monsters on
so they will be close to the PC (pictures for all).
My plan is simple , find out which amp is the least "fried" ,
then put the "hard potted" transformer in that one.
Second , test all the amps on "yours" (the one you said partially
works) , find out what the problem is where you get low output
(that is why I think one amp is good - both channels).
Then, with the extra parts in the "scrap amp" (mine) and
some careful documentation and "sniffing" around..
hopefully I will end up with one original genesis for you
and a huge empty case with lots of power for me.
I will call you,
OS
look out for the carrier's call tommorrow.
I have 2 crates and 2 4X4 beams to sit the monsters on
so they will be close to the PC (pictures for all).
My plan is simple , find out which amp is the least "fried"
,then put the "hard potted" transformer in that one.
Second , test all the amps on "yours" (the one you said partially
works) , find out what the problem is where you get low output
(that is why I think one amp is good - both channels).
Then, with the extra parts in the "scrap amp" (mine) and
some careful documentation and "sniffing" around..
hopefully I will end up with one original genesis for you
and a huge empty case with lots of power for me.
I will call you,
OS
I received the amps today.. and broke my back. OMG\
they are big..
One amp was being used as a garage band amp or some other
BS , so I used that one for parts...
two heavy suckers (53-0-53 @ 40LBS / 1.8KVA?)
The amps were good in that one but the preamp was a ratsnest.
So, Homemodders suggestion worked out great -swap the whole
amp. Regrease all the IRF's, resolder the rails (after discharging)
this amp can Kill ! The CPU showed no faults and there was music.
🙂
Besides some melted caps and a little bias adjustment , the stealth sounds real nice (I'm not sure what 7K$ should sound like.)
Makes a great room heater as well, would be good for
canada or russia..
Another strange thing , it sounded better after It warmed up..
it sort of "melted into the walls" sonically.
OS
they are big..
One amp was being used as a garage band amp or some other
BS , so I used that one for parts...
two heavy suckers (53-0-53 @ 40LBS / 1.8KVA?)
The amps were good in that one but the preamp was a ratsnest.
So, Homemodders suggestion worked out great -swap the whole
amp. Regrease all the IRF's, resolder the rails (after discharging)
this amp can Kill ! The CPU showed no faults and there was music.
🙂
Besides some melted caps and a little bias adjustment , the stealth sounds real nice (I'm not sure what 7K$ should sound like.)
Makes a great room heater as well, would be good for
canada or russia..
Another strange thing , it sounded better after It warmed up..
it sort of "melted into the walls" sonically.
OS
I'm psyched and amazed that you got one of the amps working so quickly.
As you already know, I shipped the 3rd stealth amp to Scott Franklins shop in California. It sat there for almost 5 years and he never fixed it. I got excuse after excuse after excuse. He always said it was too complicated, too this or too that. He did charge me $50 an hour for 6 hours that he "worked on it" though.
If you're interested OS... I'll send the 3rd amp down too. That's the one that Scott supposedly spent 6 hours working on.
You just let me know.
Hang on to the exta crate, box and packing because I'm going to need it. THANKS AGAIN!
As you already know, I shipped the 3rd stealth amp to Scott Franklins shop in California. It sat there for almost 5 years and he never fixed it. I got excuse after excuse after excuse. He always said it was too complicated, too this or too that. He did charge me $50 an hour for 6 hours that he "worked on it" though.
If you're interested OS... I'll send the 3rd amp down too. That's the one that Scott supposedly spent 6 hours working on.
You just let me know.
Hang on to the exta crate, box and packing because I'm going to need it. THANKS AGAIN!