That is a BIG copper donut! You could do some bicep curls or bench presses with those things! 😀
I can't wait to see what OS builds with the extra amp chassis and parts. I'm sure it'll be something special.
In the future when other stealth owners search the net for a repair tech, they'll probably find this thread and realize there is someone out there who can/will repair them.
Here's #3 all packed and ready to ship out. 🙂
I can't wait to see what OS builds with the extra amp chassis and parts. I'm sure it'll be something special.
In the future when other stealth owners search the net for a repair tech, they'll probably find this thread and realize there is someone out there who can/will repair them.
Here's #3 all packed and ready to ship out. 🙂
You are a good packer , don.
I did save a full stealth amp module and the cpu from the
"scrap" amp.
and a cpu board , it works, too.
That is the 8088 and the eprom (memory)
Hooked to the eprom is the big cap (5v- 1F) it acts like the battery.
I tested the preset memory... if you unplug the amp for a hour,
it remembers all the presets. If you unplug the amp overnight it
loses the memory after 2+ hours. This seems to be normal , as the backup is a large cap,
not a lithium cell like I originally suspected.
Man , it was hard to dig those toroids out of the metal box ,
anyway my stealth is "gutted"
the forums. To keep under 80LBS. I will just use one of the
1.8kva trafo's and for a amp , most likely FA2T with 8 OP
trannies for each channel.
I REALLY love the sound of this class A , but 160lbs + 35c rooms
are not my thing , I have a custom rack mount entertainment center and that would be WAY too much heat..
I turned the heat off in the house last night and the stealth
kept my 3 center rooms at 70F all by itself. 😱
OS
I did save a full stealth amp module and the cpu from the
"scrap" amp.
and a cpu board , it works, too.
That is the 8088 and the eprom (memory)
Hooked to the eprom is the big cap (5v- 1F) it acts like the battery.
I tested the preset memory... if you unplug the amp for a hour,
it remembers all the presets. If you unplug the amp overnight it
loses the memory after 2+ hours. This seems to be normal , as the backup is a large cap,
not a lithium cell like I originally suspected.
Man , it was hard to dig those toroids out of the metal box ,
anyway my stealth is "gutted"
I guess I have my choice of the largest Class B amps in
the forums. To keep under 80LBS. I will just use one of the
1.8kva trafo's and for a amp , most likely FA2T with 8 OP
trannies for each channel.
I REALLY love the sound of this class A , but 160lbs + 35c rooms
are not my thing , I have a custom rack mount entertainment center and that would be WAY too much heat..
I turned the heat off in the house last night and the stealth
kept my 3 center rooms at 70F all by itself. 😱
OS
wow, you did gut it! I'm curious what the gutted chassis weighs?
They claim 160lb total weight. The transformer box full of epoxy must weigh about 90lbs or so.
So, the bias and volume levels can't be memorized for more than a couple hours? That's strange because genesis made a big deal in the brochure about how the amp will saves the set levels between listening sessions.
I wish I had bought more of the stealths that Gary had! He found 8 in a big bin (in his warehouse) marked "junk". Only 2 of them worked. He kept 2, sold me 2 and threw out the other 4 because they had been semi parted out.
I don't think you could buy a rarer amplifier today. Only 45 made. I know 4 of those were junked and are gone forever. That leaves only 41 in existence 😱
They claim 160lb total weight. The transformer box full of epoxy must weigh about 90lbs or so.
So, the bias and volume levels can't be memorized for more than a couple hours? That's strange because genesis made a big deal in the brochure about how the amp will saves the set levels between listening sessions.
I wish I had bought more of the stealths that Gary had! He found 8 in a big bin (in his warehouse) marked "junk". Only 2 of them worked. He kept 2, sold me 2 and threw out the other 4 because they had been semi parted out.
I don't think you could buy a rarer amplifier today. Only 45 made. I know 4 of those were junked and are gone forever. That leaves only 41 in existence 😱
If you leave it plugged in , it will save the presets forever
(standby power supply).The
cap is for blackouts , etc. (temporary outages)
total respect man as neutral observer of this thread. i remember reading about these amps when they came out.
having looked at the schemi it seems they combined the highest end "hifi" design with the kind of control ccts normally found in a high end mixing console.
respect !
having looked at the schemi it seems they combined the highest end "hifi" design with the kind of control ccts normally found in a high end mixing console.
respect !
OS - I'm setting up the shipping of the 3rd amp out to you in TN and shipping the repaired amp back to me in NY.
Before I finalize anything...
1. Are you ok with working on the 3rd amp? It's not a rush job. Repair it at your leisure.
2. Are you satisfied enough with the repairs and the operation of the stealth that it's ready to come home?
thanks
-Don
Before I finalize anything...
1. Are you ok with working on the 3rd amp? It's not a rush job. Repair it at your leisure.
2. Are you satisfied enough with the repairs and the operation of the stealth that it's ready to come home?
thanks
-Don
Pete, I received amp #1 this morning. I hooked it up immediately and began listening. You did a fantastic job repairing this amp!
I wanted to publically post a HUGE THANK YOU for not shying away from a complicated repair job that everyone else refused. When I say everyone else... over the last 5 years I've contacted at least 20 of the top recommended technicians in the country and no one would touch this amp.
I wish I kept a list but some of them are... audio classics, cullen circuits, genesis advanced technolgies, Paul McGowan of PS Audio, Scott Frankland, Dalbec Audio, "the stereo workshop" and many many more I can't remember now.
So... THANKS AGAIN for turning my fancy "door-stop" back into an amplifier that plays music!
I wanted to publically post a HUGE THANK YOU for not shying away from a complicated repair job that everyone else refused. When I say everyone else... over the last 5 years I've contacted at least 20 of the top recommended technicians in the country and no one would touch this amp.
I wish I kept a list but some of them are... audio classics, cullen circuits, genesis advanced technolgies, Paul McGowan of PS Audio, Scott Frankland, Dalbec Audio, "the stereo workshop" and many many more I can't remember now.
So... THANKS AGAIN for turning my fancy "door-stop" back into an amplifier that plays music!
It is a small world , I started my speaker design studies after
mr. Dalbeck showed me proper alignment of ported enclosures
and his MONSTER folded horn enclosures over in troy , NY.
That was way back in the mid 80's . After 100's of bass boxes
and japanese receiver repairs , those days of cloudy judgement
are past , but very nostolgic. 🙂
I have stealth #2 and look forward to having a good laugh
at the previous repair attempt. 😀
OS
I live within walking distance of Dalbec. Walking into their shop & showroom is like walking into a time warp. It's cool and the guys there love to talk vintage gear.
The locks on the 3rd amp do not do anything. The cover should pop off normally. I don't know why someone would have put locks on there?! I've never seen locks on an amp before. 😕
The locks on the 3rd amp do not do anything. The cover should pop off normally. I don't know why someone would have put locks on there?! I've never seen locks on an amp before. 😕
Stealth #2
I have already gotten further than the last guy. 😀 OMG , he jumpered the thermisters and made a general mess of things to try to "jumpstart" this deadly amp.
I actually got the CPU to work and then replaced one thermister to get one channel back. I am glad the last tech blew a lot of fuses or he would of fused the relay contacts with too many "jumpstarts".
Now, all the inputs switch ,but I am still left with a TOASTED left
channel. When I say toasted , it burned the traces off all the outputs , melted 2 big caps and burned out the VAS...
Damn, for 7900$ , could they have parted with a few fuses ??
I am down to getting just the left channel to work. This stealth is totally re-engineered from the earlier one , the VAS/LPT is modular and the components are different ... but close the the original. I can not imagine why the last tech did not get this amp, in 1 hour I have all but the left channel.
I think the left input stage is toast on the module as the MJE's are not blown but heat up the little audio trafo with their excessive offset. For the bad left power module , I have a working (1 noisy transistor) right CH. (from mine)to replace it with.
All that remains is to troubleshoot the left VAS (module).
BTW ,don.. My supersym (my stealth)is cooler , quieter (I can hear a little hiss from the genesis) and has the same crystal clear sound as the original class A.
both are VERY good sounding .. but one costs 50$ and the other 4K$ 😀 ...
OS
I have already gotten further than the last guy. 😀 OMG , he jumpered the thermisters and made a general mess of things to try to "jumpstart" this deadly amp.
I actually got the CPU to work and then replaced one thermister to get one channel back. I am glad the last tech blew a lot of fuses or he would of fused the relay contacts with too many "jumpstarts".
An externally hosted image should be here but it was not working when we last tested it.
Now, all the inputs switch ,but I am still left with a TOASTED left
channel. When I say toasted , it burned the traces off all the outputs , melted 2 big caps and burned out the VAS...
Damn, for 7900$ , could they have parted with a few fuses ??
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I am down to getting just the left channel to work. This stealth is totally re-engineered from the earlier one , the VAS/LPT is modular and the components are different ... but close the the original. I can not imagine why the last tech did not get this amp, in 1 hour I have all but the left channel.
I think the left input stage is toast on the module as the MJE's are not blown but heat up the little audio trafo with their excessive offset. For the bad left power module , I have a working (1 noisy transistor) right CH. (from mine)to replace it with.
All that remains is to troubleshoot the left VAS (module).
An externally hosted image should be here but it was not working when we last tested it.
BTW ,don.. My supersym (my stealth)is cooler , quieter (I can hear a little hiss from the genesis) and has the same crystal clear sound as the original class A.
both are VERY good sounding .. but one costs 50$ and the other 4K$ 😀 ...OS
Looking good OS! I'm glad your amp turned out so well too! 
😀
I emailed you a few days ago about possibly upgrading caps and whatever else you think would be necessary in stealth #2.
I know you mentioned that there are better caps availible than what genesis used. Plus, those are all around 15 years old now.
If you want to go nuts upgrading... I'm all for it. You could order whatever parts you need and I could reimburse you for them OR tell me exactly what parts you need and where to get them & I will buy them & have them sent to you.
The 1st amp has been in use almost daily. A fellow audio nut mentioned that he thought the "bias circuit is not tracking properly" because the channels (heatsinks) don't warm up equally.
With the bias set under 50... the right side gets h-o-t within 5 mins of use but the left side doesn't even get warm. When listening at low bias settings, I can hear the right speaker sounding ever so slightly better/louder/clearer than the left.
If I set the bias at 100, both heat sinks warm up equally and the sound is perfect from both channels.
It's only at lower bias settings that the ineqaulity in heat and sound output is present.
Can you test the bias circuit on the 2nd stealth to see if it's working properly at different settings?
😀I emailed you a few days ago about possibly upgrading caps and whatever else you think would be necessary in stealth #2.
I know you mentioned that there are better caps availible than what genesis used. Plus, those are all around 15 years old now.
If you want to go nuts upgrading... I'm all for it. You could order whatever parts you need and I could reimburse you for them OR tell me exactly what parts you need and where to get them & I will buy them & have them sent to you.
The 1st amp has been in use almost daily. A fellow audio nut mentioned that he thought the "bias circuit is not tracking properly" because the channels (heatsinks) don't warm up equally.
With the bias set under 50... the right side gets h-o-t within 5 mins of use but the left side doesn't even get warm. When listening at low bias settings, I can hear the right speaker sounding ever so slightly better/louder/clearer than the left.
If I set the bias at 100, both heat sinks warm up equally and the sound is perfect from both channels.
It's only at lower bias settings that the ineqaulity in heat and sound output is present.
Can you test the bias circuit on the 2nd stealth to see if it's working properly at different settings?
OS, I'm curious... what did they use to keep the trafos secure in the case of this amp? Latex caulk or the other much heavier stuff.
You mentioned this amp was redesigned compared to the other 2 stealths. Is this a later stealth? You told me the serial number but I forgot.
I think amps 1 & 2 are 0018 and 0023 of 50 built.
Post some pics of your completed amp if you can. I'd like to see it.
You mentioned this amp was redesigned compared to the other 2 stealths. Is this a later stealth? You told me the serial number but I forgot.
I think amps 1 & 2 are 0018 and 0023 of 50 built.
Post some pics of your completed amp if you can. I'd like to see it.
This is one of the last - 0048. I think this may also be the reason for your dissimilar channel thermal responses , you have one 0018 amp and one 0023 amp in your completed unit. Genesis is not consistant with it's designs. Each amp seems to be unique ,with different components and general layout.I will advise you on tweaking the channels of your present one.
A picture is worth a 1000 words.(GE silicone)
An externally hosted image should be here but it was not working when we last tested it.
You know , I only had to drill 1 hole to make my amp (3/8" trafo Bolt-photo 2) , and reused all the OEM mounting points. I even reused the output transistor holes(photo3). BTW ,see the fuses..my amp will not burn up
!An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I also have a blue LED so you can see the main trafo through the 1/2" plexiglass front window(photo 1). Not to put the genesis stealth down , but I would not trade mine for it. The class A sounds nice , but does not have the headroom mine does ... not even close!! The 30v analog module power supply is the genesis's "bottleneck" (schematic last post). As far as remote control , I can buy a digital input switcher/volume control for 60$.
John curl says he will sell just the schematic for a open loop power amp (like the stealth) for 5K$.. what BS , My cool AB amp sounds just as good if not better at concert hall levels as well as being just as silky smooth and quieter at normal levels(lower noise floor).
On the 0048 stealth I would recommend recapping as this unit has a lot of use on it (cap sleeves melted , brown traces PCB).
Let me piece it together first (fully operational) then I will PM you a BOM for the caps (all 10lbs of them
) I still can not see how they could justify 7900$ for this amp !OS
OS yours looks good! You traded the cool milled aluminum stealth power switch for a toggle switch though!? 😱 😕
How much does yours weigh? What's the wpc?
I agree about the $7900 price. I don't know how any amp is worth that kind of money. There's a lot of mark up in the high end gear I'd say.
I thought you said you put both amp boards from your stealth in mine so they're the same? My memory fails me.
When you're ready... let me know about upgrading #3 stealth. I'd like you to go right through it and swap out anything you think would be worth renewing. I want it to be better than new. 🙂
Thanks!
How much does yours weigh? What's the wpc?
I agree about the $7900 price. I don't know how any amp is worth that kind of money. There's a lot of mark up in the high end gear I'd say.
I thought you said you put both amp boards from your stealth in mine so they're the same? My memory fails me.
When you're ready... let me know about upgrading #3 stealth. I'd like you to go right through it and swap out anything you think would be worth renewing. I want it to be better than new. 🙂
Thanks!
ostripper said:
I will advise you on tweaking the channels of your present one.
On the 0048 stealth I would recommend recapping as this unit has a lot of use on it (cap sleeves melted , brown traces PCB).
Let me piece it together first (fully operational) then I will PM you a BOM for the caps (all 10lbs of them
How ya making out on the repairs OS?
You mentioned tweaking my current amp so the bias is the same on each channel. Is that something I can do?
You see the trimmer? (blue square that says offset) this is the only control on the amp boards. I did adjust those (both of your channels have under 50mv offset). What happened is in the last 2 days before the shipper arrived, one channel broke out in static. So I could ship it to you I gave you the amp out of the other stealth. I also adjusted that one (<50mv) . The default biasing is controlled by the CPU , I deduced this by seeing the differences between amp boards.
Do the sides heat up at full bias ? , I fear that there is a possibility that the minimum bias is "locked" by the circuit itself.
On the one I have now (since it is toasted) I will make the necessary changes to make both sides into equal room heaters.
Really getting deep into these stealth's , I have noticed that they use the PCB traces as the fuses (safety factor instead of fuses).
Genesis could not keep the circuit OR the layout consistent from amp to amp 🙁 , and they jumpered traces plus added parts (layout errors in PCB). Not "in line" with a $7900 unit.
At the moment , while not homeless , I am low on resources ($$$), I don't intend to charge much to finish this amp. Hell ,If you just get me some more supersym parts , I'll be happy. 🙂
OS
PS.... lgreen , I have gotten many emails for supersyms ,so I WILL
start a thread with PCB layout. The amp still lives , and is ROCK SOLID - final version, no changes needed.
Do the sides heat up at full bias ? , I fear that there is a possibility that the minimum bias is "locked" by the circuit itself.
On the one I have now (since it is toasted) I will make the necessary changes to make both sides into equal room heaters.
Really getting deep into these stealth's , I have noticed that they use the PCB traces as the fuses (safety factor instead of fuses).
Genesis could not keep the circuit OR the layout consistent from amp to amp 🙁 , and they jumpered traces plus added parts (layout errors in PCB). Not "in line" with a $7900 unit.
At the moment , while not homeless , I am low on resources ($$$), I don't intend to charge much to finish this amp. Hell ,If you just get me some more supersym parts , I'll be happy. 🙂
OS
PS.... lgreen , I have gotten many emails for supersyms ,so I WILL
start a thread with PCB layout. The amp still lives , and is ROCK SOLID - final version, no changes needed.
Attachments
os, both sides heat up equally at full bias (100) but they don't heat up equally at the lower bias settings. After 10 mins or so of listening at the lowest bias setting (20), The left side stays cold while the right side is so hot that I can't hold my hand on it for long. This can't be right.
If you need funds for labor or to buy the new caps and other parts for stealth #3, let me know. I will paypal you right now. Just tell me what you need.
Ask and ye shall receive. 😉
EDIT - D0N SAYS THIS PROBLEM IS FIXED
If you need funds for labor or to buy the new caps and other parts for stealth #3, let me know. I will paypal you right now. Just tell me what you need.
Ask and ye shall receive. 😉
EDIT - D0N SAYS THIS PROBLEM IS FIXED
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