Is there a list of parts besides the dual filyer caps that blow and the more beefy rectifier that are commonly changed out when gojng over this amp, for maybe sound improvement etc?
You need a properly assembled capacitor PCB. That includes square pins, proper capacitors and the insulation sheet. The 6A rectifiers are simply 6A axial with higher than 400 VDC PIV.
I get units in where folks have installed Ebay kits, or their own unsuitable Frankenstein assemblies. There are some who do it right of course. So you know, Carver service only sold these complete, never a bare PCB. How the PCB is made is important, as are how the pins are installed, soldered and finished. My favorite botch job is some radial caps with the leads stuck into the power supply PCB. What were they thinking ???? The worst examples of those use no name capacitors, or fakes of good brands. Guess where they shopped?
I have improved these amplifiers, but this is not a component swap deal and no job for anyone inexperienced. You really do not want to attempt "op amp rolling". These can oscillate easily and with the amount of power available the resulting damage could be severe. Similar to building a race engine. You don't just bolt parts in. The higher power the amplifier (or engine), the more impressively things can go wrong.
I get units in where folks have installed Ebay kits, or their own unsuitable Frankenstein assemblies. There are some who do it right of course. So you know, Carver service only sold these complete, never a bare PCB. How the PCB is made is important, as are how the pins are installed, soldered and finished. My favorite botch job is some radial caps with the leads stuck into the power supply PCB. What were they thinking ???? The worst examples of those use no name capacitors, or fakes of good brands. Guess where they shopped?
I have improved these amplifiers, but this is not a component swap deal and no job for anyone inexperienced. You really do not want to attempt "op amp rolling". These can oscillate easily and with the amount of power available the resulting damage could be severe. Similar to building a race engine. You don't just bolt parts in. The higher power the amplifier (or engine), the more impressively things can go wrong.
I agree here with Anatech.
It can be improved for sure, materials available today might be better, especially op amps. I've done it. But honestly I really don't advice doing it. It is looking for trouble. Carver designed his amps to work, to survive and to be able to take abuse. Changing things and you will compromise it. It means some serious work, experience and good equipment to do so. My thaughts exactly that where there is a lot of energy available it will also cause plenty of spectacular damage.
My advice is the same. Leave it how it is. There is no such thing like "manual how to make audiophile mods" to Carver.
Please don't get me wrong, I don't want to be rude or anything just I know what might happen and also I'm speaking from experience. Been there, done that.
Cheers
It can be improved for sure, materials available today might be better, especially op amps. I've done it. But honestly I really don't advice doing it. It is looking for trouble. Carver designed his amps to work, to survive and to be able to take abuse. Changing things and you will compromise it. It means some serious work, experience and good equipment to do so. My thaughts exactly that where there is a lot of energy available it will also cause plenty of spectacular damage.
My advice is the same. Leave it how it is. There is no such thing like "manual how to make audiophile mods" to Carver.
Please don't get me wrong, I don't want to be rude or anything just I know what might happen and also I'm speaking from experience. Been there, done that.
Cheers
I understand but in reality i already have to change out 4 transistors that are obsolete, a few burnt resistors, a rectifier, etc replacing them with somwthing that i hope makes it behave properly with guidence from you folks.
There is nothing wrong with upgrading the amp with modern parts that are better that were not available when it was built if has any sort of meaningful impact.
There is nothing wrong with upgrading the amp with modern parts that are better that were not available when it was built if has any sort of meaningful impact.
I totally understand you. I claim those amps are not rare and modifying is not destroying some valuabke original super rare piece of equipment.
What I'm saying is with swapping op amp or those vas transistors you risk to cause nasty oscillation and amp will self destroy or even worse went into oscillation at high frequency under load and maybe blow your nice tweeters or something. Because those amps are old, components have drifted, material used is a little bit different from batch to batch it would be really hard to sughest what to do and where the problem would be. My amp might be behaving well and your might be oscillating and so on. You know what I mean, and from that power supply there is roughly 1500W available and that will do plenty of damage. Because of this unpredictable situation I would not dare even suggest what to do, what to modify. Nobody would be able to help you if something would go wrong.
Again I'm telling you this from experience. I have modified Carver M400. I even re-wound mag coil fron 117V to 230V. I did all the things which would make Anatech hair to stand up. It took me long long hours to get things right and that's why I strongly suggest against such games.
If you would really like to explore Carver circuit probably right way would be to attack the project with LtSpace or something similar. After that probably best thing in hi-fi sense would be to draw new boards and build totally new amp from scratch. I would took out mag coil and would rather usenbig cap banks and big massive transformer. Schematic which I would follow would probably be PM1201 which was the latest and the last variation of this schematic. I think itnis the most refined one with emitter resistors in paralleled transistors and so on. To me that schematic makes sense.
Actually years ago I started doing exactly that. I have boardsnhalf drawn. But time is big limitation for me. You know, too many projects, day has only 24 hours and few of those you have to steal somehow to get a little bit of sleep.
Of course, we can discuss things, that's why we are here.
Best regards
What I'm saying is with swapping op amp or those vas transistors you risk to cause nasty oscillation and amp will self destroy or even worse went into oscillation at high frequency under load and maybe blow your nice tweeters or something. Because those amps are old, components have drifted, material used is a little bit different from batch to batch it would be really hard to sughest what to do and where the problem would be. My amp might be behaving well and your might be oscillating and so on. You know what I mean, and from that power supply there is roughly 1500W available and that will do plenty of damage. Because of this unpredictable situation I would not dare even suggest what to do, what to modify. Nobody would be able to help you if something would go wrong.
Again I'm telling you this from experience. I have modified Carver M400. I even re-wound mag coil fron 117V to 230V. I did all the things which would make Anatech hair to stand up. It took me long long hours to get things right and that's why I strongly suggest against such games.
If you would really like to explore Carver circuit probably right way would be to attack the project with LtSpace or something similar. After that probably best thing in hi-fi sense would be to draw new boards and build totally new amp from scratch. I would took out mag coil and would rather usenbig cap banks and big massive transformer. Schematic which I would follow would probably be PM1201 which was the latest and the last variation of this schematic. I think itnis the most refined one with emitter resistors in paralleled transistors and so on. To me that schematic makes sense.
Actually years ago I started doing exactly that. I have boardsnhalf drawn. But time is big limitation for me. You know, too many projects, day has only 24 hours and few of those you have to steal somehow to get a little bit of sleep.
Of course, we can discuss things, that's why we are here.
Best regards
P.s.
Even simulation would only take you half way there. See the boards there, see how relatively thin wires are all the way around, how wires are twisted, how on the board traces run long in parallel. Circuit might be stable in such enviroment with components they have used but it is delicate "ecosystem".
Cheers
Even simulation would only take you half way there. See the boards there, see how relatively thin wires are all the way around, how wires are twisted, how on the board traces run long in parallel. Circuit might be stable in such enviroment with components they have used but it is delicate "ecosystem".
Cheers
No man. Those are going to be just fine. PM1201 used those from factory. Those are relatively slow and it won't cause any trouble. And robust enough to be able to drive what's behind
You by chance got a part number for the 6A rectifier?
Filtering on Digikey only gives me thru hole options and no chasi mounts that look similar.
P1000 series should work.
Letter at the back is voltage rating. 600V is probably good choice. It is thicker one and you will have to stack them a little bit to fit.
Letter at the back is voltage rating. 600V is probably good choice. It is thicker one and you will have to stack them a little bit to fit.
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I must have misunderstood what you were telling me i should change out.
P1000 looks like a single diode.
I thiught you were talking about replacing the 125v square package 4 pin rectifier mounted to the chassi.
P1000 looks like a single diode.
I thiught you were talking about replacing the 125v square package 4 pin rectifier mounted to the chassi.
Ah...
Anatech and I were suggesting to replace those singke diodes which are just 3A ones. Those were later replaced by 6A or even 10A at some late production amps.
That square bridge rectifier I've also seen to fail. Maybe 2 times in some really badly blown amps which I've bought. That one anything same size same rating would do the job. You are after 25 or 35A one which should take anything from 400V up. 35A 1000V is probably common one and cheap.
I would buy some good one from good brand. Fairchild, ON, Vishay...such brands I would trust. No name generic ones, the cheapest ones out there I try to avoid. Like everything today. But it is really not that critical which part you buy. And I would even leave it alone if it's working. I would replace those 3A diodes for some bigger ones though. But even that if you are using it for home hi-fi I woukd maybe keave thise as they are. Be aware, replacing those diodes is kind of nasty job. There is no space, trafo wires are in the way ect.
Best regards, Taj
Anatech and I were suggesting to replace those singke diodes which are just 3A ones. Those were later replaced by 6A or even 10A at some late production amps.
That square bridge rectifier I've also seen to fail. Maybe 2 times in some really badly blown amps which I've bought. That one anything same size same rating would do the job. You are after 25 or 35A one which should take anything from 400V up. 35A 1000V is probably common one and cheap.
I would buy some good one from good brand. Fairchild, ON, Vishay...such brands I would trust. No name generic ones, the cheapest ones out there I try to avoid. Like everything today. But it is really not that critical which part you buy. And I would even leave it alone if it's working. I would replace those 3A diodes for some bigger ones though. But even that if you are using it for home hi-fi I woukd maybe keave thise as they are. Be aware, replacing those diodes is kind of nasty job. There is no space, trafo wires are in the way ect.
Best regards, Taj
I've never seen the 25A bridge rectifier fail except in one unit that was connected to 500 VAC (120VAC unit).
Yes, replace the 3A rectifier (singles) with 6A rectifiers. They are larger, so you mount the ones close to the board skipping the adjacent one, then mount the next two higher. Nice and neat. There is no need to install any higher current rating, and use normal rectifiers. Don't get fancy. Absolutely use good quality standard, known brands as Tajzmaj mentioned.
Yes, replace the 3A rectifier (singles) with 6A rectifiers. They are larger, so you mount the ones close to the board skipping the adjacent one, then mount the next two higher. Nice and neat. There is no need to install any higher current rating, and use normal rectifiers. Don't get fancy. Absolutely use good quality standard, known brands as Tajzmaj mentioned.
I have been spending some time going over the schematics just trying to familiarize myself with the layout try to understand what I can and learn what I don't understand, and I'm trying to figure out where the 12 volts are coming from.
Does anybody have the power supply schematic handy? Is the 12 volts being supplied from transistor 3055 that has the 50 volts connected to the collector and the output is 12 volts, or does that little circuit have 50 volts on The Collector and 12 volts on the emitter and the 12 volts is coming from somewhere else, and what is this little circuit doing?
Does anybody have the power supply schematic handy? Is the 12 volts being supplied from transistor 3055 that has the 50 volts connected to the collector and the output is 12 volts, or does that little circuit have 50 volts on The Collector and 12 volts on the emitter and the 12 volts is coming from somewhere else, and what is this little circuit doing?
It is dropped from low rails which are 50V at yout amp? I have only schematic for PM1.5 on hand and it is Q7 and Q8 with resistors and zeners which are around. That is where it is dropped to +-12V.
Yes thats the small circuit.
Yeah I wasn't sure if that was producing the 12 volts or if the 12 volts was being supplied to that other side as well coming from somewhere else. I was playing around with circuit simulation just trying to understand some stuff and the circuit simulation was not producing what I thought that circuit was doing.
Thank you for the clarification.
Yeah I wasn't sure if that was producing the 12 volts or if the 12 volts was being supplied to that other side as well coming from somewhere else. I was playing around with circuit simulation just trying to understand some stuff and the circuit simulation was not producing what I thought that circuit was doing.
Thank you for the clarification.