a half a milliamp is enough to hurt. A transformer is a cheap investment that CAN'T be avoided.
if you use a grounded plug, the ground wire (green) goes to the chassis. if the system pops a fuse then it had mains voltage levels on the chassis. a 2 prong plug is more dangerous as the chassis could be hot or neutral depending on the orientation of the plug.
if you use a grounded plug, the ground wire (green) goes to the chassis. if the system pops a fuse then it had mains voltage levels on the chassis. a 2 prong plug is more dangerous as the chassis could be hot or neutral depending on the orientation of the plug.
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anatech,
I am confused by your "Ground loop control". I have never been a fan of using a resistor to connect from the IEC ground to the chassis. Anything that can be burned out by an amplifier malfunction should not be able to lift / disconnect the chassis to ground connection. The wire should be large enough to withstand any fault current, including a short from Hot, or from the input fuse. Using a resistor is not a good idea there. You are relying on the mains power panel fuse or circuit breaker to keep the house from burning down. (and in the case of a ground fault interrupter to protect you).
I have worked in conjunction with various companies and UL on what works, what makes sense, and what passes UL and CSA for safety.
My amplifiers IEC connector Hot terminal connects to a fast blow fuse in series with a slow blow fuse, and only after that to a power switch, and then on to the power transformer primary. The other end of the primary is connected to Neutral. Traveling to a friends with your amplifier? Then check his power outlets before plugging in.
I have converted all my old amplifiers to use the IEC connector, and to have direct connection from IEC ground to the amplifier chassis. The only old amplifiers I will use have real power transformers with real isolation.
Some amplifiers do not connect the common terminal of the output transformer secondary to the chassis, and to ground. Floating the secondary is a bad idea.
Yes, some feedback schemes do not connect the common terminal to chassis and ground, but in that case, either the 4, 8, or 16 Ohm tap IS connected to chassis and ground.
I have seen 2 output transformer failure modes that would otherwise have been unsafe: 1. The primary (think B+) was shorted to the secondary. 2. The primary (think B+) was shorted to the laminations that are metallically connected to the chassis.
What happens when the power transformer hot end of the primary winding shorts to the laminations ? (it will be very bad if there is no direct chassis to ground connection).
I subscribe to the surviving spouse syndrome theory, do it wrong and there will be a surviving spouse.
I am confused by your "Ground loop control". I have never been a fan of using a resistor to connect from the IEC ground to the chassis. Anything that can be burned out by an amplifier malfunction should not be able to lift / disconnect the chassis to ground connection. The wire should be large enough to withstand any fault current, including a short from Hot, or from the input fuse. Using a resistor is not a good idea there. You are relying on the mains power panel fuse or circuit breaker to keep the house from burning down. (and in the case of a ground fault interrupter to protect you).
I have worked in conjunction with various companies and UL on what works, what makes sense, and what passes UL and CSA for safety.
My amplifiers IEC connector Hot terminal connects to a fast blow fuse in series with a slow blow fuse, and only after that to a power switch, and then on to the power transformer primary. The other end of the primary is connected to Neutral. Traveling to a friends with your amplifier? Then check his power outlets before plugging in.
I have converted all my old amplifiers to use the IEC connector, and to have direct connection from IEC ground to the amplifier chassis. The only old amplifiers I will use have real power transformers with real isolation.
Some amplifiers do not connect the common terminal of the output transformer secondary to the chassis, and to ground. Floating the secondary is a bad idea.
Yes, some feedback schemes do not connect the common terminal to chassis and ground, but in that case, either the 4, 8, or 16 Ohm tap IS connected to chassis and ground.
I have seen 2 output transformer failure modes that would otherwise have been unsafe: 1. The primary (think B+) was shorted to the secondary. 2. The primary (think B+) was shorted to the laminations that are metallically connected to the chassis.
What happens when the power transformer hot end of the primary winding shorts to the laminations ? (it will be very bad if there is no direct chassis to ground connection).
I subscribe to the surviving spouse syndrome theory, do it wrong and there will be a surviving spouse.
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the IEC ground pin connects directly to chassis metal frames usually at one of the screws used to fix that inlet, this completes the safety aspect...
the psu ground is another matter and may not connect to chassis directly but thru a resistor where signal currents is low as in input jacks...
this is what i practice, worked for me too...
the psu ground is another matter and may not connect to chassis directly but thru a resistor where signal currents is low as in input jacks...
this is what i practice, worked for me too...
My B+ secondary center tap connects directly to the first filter cap negative (whether it is cap input or choke input). Then from there it connects directly to the chassis. That makes for a very short ground loop of secondary, rectifiers, capacitor. After that, the ground connection of the first cap connects to chassis ground and any other B+ filter caps negative terminals. This second ground connection becomes the central ground of the amp for signal and B+. This method reduces ground loop noise.
The RCA input connectors use insulating washers where they are mounted on the chassis, but the outside connection (signal ground) connects directly through a wire to the amp's central ground. Again, I do not use any semi-isolating resistor here.
It works for me.
The RCA input connectors use insulating washers where they are mounted on the chassis, but the outside connection (signal ground) connects directly through a wire to the amp's central ground. Again, I do not use any semi-isolating resistor here.
It works for me.
The same method can be used for bridge rectifiers, connect the bridge negative directly to the first capacitor negative terminal with the shortest wires possible to and from the secondary, to and from the bridge, and to the first capacitive negative terminal, and likewise from the bridge + out to the first capacitor positive terminal. This constitutes an aperture of a magnetic loop, and also of a ground loop. Smaller is less likely to interfere. Then connect from there to the other filter cap negatives and to the amp's central ground and chassis of the amp.
If you locate the aperture in the wrong place, and wrong magnetic orientation, it may transmit magnetically to another circuit or part (like directly under an output transformer that is in the same field orientation).
Attention to details pays off.
If you locate the aperture in the wrong place, and wrong magnetic orientation, it may transmit magnetically to another circuit or part (like directly under an output transformer that is in the same field orientation).
Attention to details pays off.
Hi 6A3sUMMER,
If you read my post again, I was pretty direct about the ground being bonded directly to the chassis securely. That is inline with what the safety organizations are saying.
The audio common can safely float, but it should be referenced to safety ground. Because no current normally flows in this circuit connection, the use of a resistor is both safe and effective. Many commercial brands design their amplifiers (in this case) exactly the way I have described it.
Lightning can and will blow traces open and conductors apart. I have seen this many times. Losing a resistor is cheap compared to the other damage I mentioned.
-Chris
If you read my post again, I was pretty direct about the ground being bonded directly to the chassis securely. That is inline with what the safety organizations are saying.
The audio common can safely float, but it should be referenced to safety ground. Because no current normally flows in this circuit connection, the use of a resistor is both safe and effective. Many commercial brands design their amplifiers (in this case) exactly the way I have described it.
Lightning can and will blow traces open and conductors apart. I have seen this many times. Losing a resistor is cheap compared to the other damage I mentioned.
-Chris
Many of my amplifiers are quite old.
But they have been modified to use the latest safety techniques that can be applied.
Reduce shock hazard.
Reduce fire hazard.
Make them sound good.
Keep it the way it was?
Shock hazard
Fire hazard
Sounds bad
No thanks!
I use the old power transformers, but I use them at lower currents than they were originally designed for. Just a good way to use an old transformer, they run cooler.
But they have been modified to use the latest safety techniques that can be applied.
Reduce shock hazard.
Reduce fire hazard.
Make them sound good.
Keep it the way it was?
Shock hazard
Fire hazard
Sounds bad
No thanks!
I use the old power transformers, but I use them at lower currents than they were originally designed for. Just a good way to use an old transformer, they run cooler.
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Hi 6A3sUMMER,
By changing things at this fundamental level you may be forcing a ground loop.
I restore and rebuild lots of old 2 wire equipment, and have for over 40 years. There is a proper way to do this, and often changing the AC cord to 3 wire will cause basic problems. Everything from "it won't plug into the preamp anymore" to electrical noise that you created with that 3 wire cord. True, no shock hazard, but I check the leakage before I release anything back into service.
If there aren't customer units, I guess you are simply destroying the old sets you come across for the transformers.
-Chris
You aren't listening at all. There isn't a shock hazard when you restore a power transformer type appliance. Normally there isn't exposed metal with these things.
By changing things at this fundamental level you may be forcing a ground loop.
I restore and rebuild lots of old 2 wire equipment, and have for over 40 years. There is a proper way to do this, and often changing the AC cord to 3 wire will cause basic problems. Everything from "it won't plug into the preamp anymore" to electrical noise that you created with that 3 wire cord. True, no shock hazard, but I check the leakage before I release anything back into service.
If you pull those (why??), do your customers pay for new transformers, or do they lose their unit? Most times the old transformers are fine, and news flash, they normally operated at higher temperatures - by design. A new transformer to replace the one you pulled will also run warm to hot if it is the same size and mounting. You would be much further ahead to leave the transformers in the units and order the exact ones you need for your projects.
If there aren't customer units, I guess you are simply destroying the old sets you come across for the transformers.
-Chris
anatech,
I guess I missed the fact that you did state using a direct connection to the chassis.
I believe a direct lighting hit may not allow any practical method to prevent a serious amplifier failure.
But a product with a lightning induced 2kV pulse on the power line might just survive. However, if the pulse happens to be differential between say a CD player and a power amp, with the loop consisting of a common power outlet, two power cords, and RCA cables for signals, that loop may easily open the ground loop eliminator resistor. Part of that equation of 'works or fails' is the reverse transfer function of a coaxial or other cable (the RCA phono cable, XLR cable, or similar). The induced voltage in the signal wire(s) as a result of the induced current in the ground wire can be quite a problem. And depending on the terminations at both ends, can really clean out the circuits at one, the other, or both ends. Think something similar to EMP, only smaller.
Some commercial products seem to need ground loop eliminator resistors. I never found them to be necessary in any of my Hi Fi setups.
I guess I missed the fact that you did state using a direct connection to the chassis.
I believe a direct lighting hit may not allow any practical method to prevent a serious amplifier failure.
But a product with a lightning induced 2kV pulse on the power line might just survive. However, if the pulse happens to be differential between say a CD player and a power amp, with the loop consisting of a common power outlet, two power cords, and RCA cables for signals, that loop may easily open the ground loop eliminator resistor. Part of that equation of 'works or fails' is the reverse transfer function of a coaxial or other cable (the RCA phono cable, XLR cable, or similar). The induced voltage in the signal wire(s) as a result of the induced current in the ground wire can be quite a problem. And depending on the terminations at both ends, can really clean out the circuits at one, the other, or both ends. Think something similar to EMP, only smaller.
Some commercial products seem to need ground loop eliminator resistors. I never found them to be necessary in any of my Hi Fi setups.
Is the chassis of a 2 wire Dyna Stereo 70 chassis exposed to the customer, even with the painted metal cage over the top? Is the plug polarized? Is there leakage current from the chassis to ground? Can those old transformers (power and output) short to the chassis? Would any old Dyna Stereo 70 meet today's UL and CSA safety standards? I live in 2018, not 1959.
How about the old Hallicrafters SX40 that had the power transformer overheat and fail?
I do not sell amplifiers to customers. I use the old transformers, I do not 'pull them out'. I am sorry that I 'destroy' old amplifiers.
My power amps work with any number of preamps and direct connected signal sources, phono preamps, with or without passive volume controls, etc. What ground loop?
I am so glad I never saw a souped up 1932 Ford with a V8 and automatic transmission.
How about the old Hallicrafters SX40 that had the power transformer overheat and fail?
I do not sell amplifiers to customers. I use the old transformers, I do not 'pull them out'. I am sorry that I 'destroy' old amplifiers.
My power amps work with any number of preamps and direct connected signal sources, phono preamps, with or without passive volume controls, etc. What ground loop?
I am so glad I never saw a souped up 1932 Ford with a V8 and automatic transmission.
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I'm not sure it can safely float. If there is a fault which causes the circuit to have mains voltage on it the connection to safety ground can cause the fuse to blow.
Shouldn't audio common be referenced to the chassis for EMI suppression?
A power transformer mounted on a steel chassis transmits magnetic fields across the chassis. A filter choke on a steel chassis does the same. It also causes a small voltage differential across/along the chassis.
Even a power transformer or a filter choke on an aluminum chassis will cause a small voltage differential across/along the chassis.
These small differential voltages can enter the circuit if you use more than one grounding point on the chassis. Hum is a difficult thing to prevent. Some multiple ground connections at different points on the chassis may be allowed, but "your mileage may vary".
Find and use a technique that works for you and stick to it, until you find a combination of amplifiers and signal sources that no longer works for you.
That is why I connect the safety ground and central circuit ground to a single point on the chassis. Then I insulate the RCA input jacks from the chassis with insulating washers, but that requires me to use wires to connect the RCA input jack grounds to the central ground.
Getting an amplifier to have less than 100uV hum and noise at the 8 Ohm output terminals requires such attention to details. Sometimes I can not easily get the hum and noise to less than 300 or 400uV, but I sometimes stop trying to get it lower than that.
That works for me in my systems and with my loudspeakers. I have found far worse on some commercial products.
As I said earlier, EMI is a complex thing. There are radiated emissions (magnetic and electrostatic fields), conducted differential emissions, and conducted common mode emissions.
It is true that "Grounds are Commonly Misunderstood". (seriously, and pun intended too). A wire does not simply connect two points together such that the voltage is constant at both ends of the wire. A wire is an inductor. How good is a 3 foot power cord at connecting the input and output ends with zero volts drop along the inductance of the wire, especially when the EMI may be from the fast rise and fall of a CD player's power supply 50kHz switcher, and all its harmonic series? Can 50kHz beat with 44kHz or higher frequency from a CD player clock; or how about some of the harmonics of those two signals. Will that fall into the audible audio band? Could Murphy's Law be in effect? Is this just an inner layer of the onion, or has it ever appeared in one of your setups?
Even a power transformer or a filter choke on an aluminum chassis will cause a small voltage differential across/along the chassis.
These small differential voltages can enter the circuit if you use more than one grounding point on the chassis. Hum is a difficult thing to prevent. Some multiple ground connections at different points on the chassis may be allowed, but "your mileage may vary".
Find and use a technique that works for you and stick to it, until you find a combination of amplifiers and signal sources that no longer works for you.
That is why I connect the safety ground and central circuit ground to a single point on the chassis. Then I insulate the RCA input jacks from the chassis with insulating washers, but that requires me to use wires to connect the RCA input jack grounds to the central ground.
Getting an amplifier to have less than 100uV hum and noise at the 8 Ohm output terminals requires such attention to details. Sometimes I can not easily get the hum and noise to less than 300 or 400uV, but I sometimes stop trying to get it lower than that.
That works for me in my systems and with my loudspeakers. I have found far worse on some commercial products.
As I said earlier, EMI is a complex thing. There are radiated emissions (magnetic and electrostatic fields), conducted differential emissions, and conducted common mode emissions.
It is true that "Grounds are Commonly Misunderstood". (seriously, and pun intended too). A wire does not simply connect two points together such that the voltage is constant at both ends of the wire. A wire is an inductor. How good is a 3 foot power cord at connecting the input and output ends with zero volts drop along the inductance of the wire, especially when the EMI may be from the fast rise and fall of a CD player's power supply 50kHz switcher, and all its harmonic series? Can 50kHz beat with 44kHz or higher frequency from a CD player clock; or how about some of the harmonics of those two signals. Will that fall into the audible audio band? Could Murphy's Law be in effect? Is this just an inner layer of the onion, or has it ever appeared in one of your setups?
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Hi 6A3sUMMER,
We all know the answers to your questions, restate them as points instead of questions. Now, you may live in these times, but you are not doing the owner of this equipment any favors by grounding the chassis. As for living in 1959, yes, I was alive then and my current favorite tube amplifier was sold during that year. I have rebuilt it in 2-wire mode, as it should be. In fact, I am designing a new amplifier inspired by that amplifier. It will use a 3 wire cord, but will be designed for that from the start.
For current regulations, you need to either design a double insulated device, or ground the chassis directly to the safety ground. I have said this already, so you still are not reading posts very carefully. Take your time and try not to be so fired up over everything.
Hi DF96,
Thank you. Exactly.
Yes, and if there is a problem the user can easily get a shock. But that is the nature of that type of equipment. However, the normal connection to the AC supply to the chassis is typically a high voltage capacitor. That's why we replace them with a modern one that is more reliable.
We all know the answers to your questions, restate them as points instead of questions. Now, you may live in these times, but you are not doing the owner of this equipment any favors by grounding the chassis. As for living in 1959, yes, I was alive then and my current favorite tube amplifier was sold during that year. I have rebuilt it in 2-wire mode, as it should be. In fact, I am designing a new amplifier inspired by that amplifier. It will use a 3 wire cord, but will be designed for that from the start.
For current regulations, you need to either design a double insulated device, or ground the chassis directly to the safety ground. I have said this already, so you still are not reading posts very carefully. Take your time and try not to be so fired up over everything.
This failure has killed people in the recent past, HAMs who know better in fact. But then, this is why the standards have changed. Equipment built before the date are exempt from the standards, but you still have to check for leakage currents.
If you take these transformers out of equipment that was repairable, you are destroying equipment needlessly. I truly have a deep dislike for people who do things like that. Don't be so silly, repair the repairable ones and enjoy them, or sell them on before you hack them. Take your transformers from lost causes, or buy them new like everyone else. I think it is a crime to wreck a piece of equipment just for the power transformer and maybe outputs. I have a couple stereo units that will be broken down, but they were serviced by idiots and destroyed, cosmetically and electrically. Anything else I run into are repaired or moved down the line before I sink time into them.
You're either lucky or you build them correctly. More trouble with ground loops occur with three wire grounded equipment than two wire types. I know because I get old equipment in for hum problems, many that were converted to three wire that didn't hum before. You tell me.
Hi DF96,
Thank you. Exactly.
This has been a very informative thread for me, in fact much of it over my head, it appears that being a tech replacing bad components is very different then actually knowing design, I have been replacing bad components without this knowledge of safety, and I been buying replacement power cords from antique wire supply, but the plugs are not polarized. They are cloth wire so the look is authentic, but now I am ordering a lot of polarized 2 prong plugs to rewire them with. Thanks to all of you
anatech,
I can see you are an expert restorer, that is to be commended. I have a very good long term friend who also is expert at restoring all the way back to the TRF era. But he does new design, and everything else in-between.
This site has restorers, modifiers, upgraders, those who re-design amplifiers, those who build kits, and those who design from scratch (that does not even describe all the types who read and post on these vacuum tube threads). It is a very good thing to have all of those persons, we all can learn something, and can have multiple ways to have amplifiers that we enjoy.
How rigid do we need to be in our particular expertise and philosophy of how to work on old amplifiers? Under the 100% Restore Only criteria, I wonder if anybody should use plastic coupling caps. Should they hunt for and use the old leaky Black Beauty caps that so often go leaky with age (or carefully remove the outer plastic from the Black Beauty and insert a new paper capacitor inside). And then they can replace the 'new'/restored almost Black Beauty paper capacitor after time when it goes leaky.
The Dyna Stereo 70 used a 2 wire non polarized power cord. There was no capacitor from either the neutral nor the hot wire to the chassis (and no way to tell which wire was which). There was no capacitor across the primary power switch. The only capacitance to the chassis was from the power transformer, filter choke, output transformers, and the ceramic capacitors connecting ground capacitively to the center taps of the two 6.3V filament secondaries.
By the way, the Dyna Stereo 70 was not ever a hot chassis (unless one of the transformers, chokes, or wiring shorted to the chassis). There are hot chassis, grounded chassis, and a 3rd class that is neither hot nor grounded.
I am sorry for the questions again, but here goes: If the Dyna Stereo 70 is restored to original, how often do I need to check the leakage currents to the chassis? And which way should I plug the 2 wire into a modern 3 wire outlet? Will the leakage current be the same for each way I plug it in?
All my other vacuum tube amplifiers started life with similar 2 wire power cords. They are now modified for 3 wire power cords. They also did not, and still do not have any capacitor connected to the chassis. and there is no resistor connected from hot, neutral, or power ground to the chassis. the chassis is connected directly to the power ground, and inputs and outputs are connected by wire to the chassis.
Since my house, and other places I take old amplifiers to have 3 wire grounded outlets, I think it is safer to have the chassis of a Dyna ST70 grounded. And that goes for many other amplifiers with old transformers. Of course any capacitive currents from power transformer are conducted to ground (and yes, could potentially create a ground loop).
As I said, I have even seen a brand new transformer shorted from primary to secondary, and a brand new transformer shorted from primary to laminations. And then there are the other transformers that have shorted after decades of good service.
For me, safety first. Ground loops second. I will cross the ground loop bridge when I get one that needs fixing.
One of the most dangerous places I worked was on board a US naval destroyer. "grounded" metal was everywhere (Power system 'ground'). And 110V was statistically the highest rate killer of sailers that died by electrocution.
There is probably some old equipment that nobody should be using without either special modification, or that now has a chassis or other exposed metal covered, or grounded. An electrocution of a person that used an old electric hand drill is an example of what not to do when working under a house on wet ground. That is why the new drills have to meet a new standard, double insulated that you mentioned.
I can see you are an expert restorer, that is to be commended. I have a very good long term friend who also is expert at restoring all the way back to the TRF era. But he does new design, and everything else in-between.
This site has restorers, modifiers, upgraders, those who re-design amplifiers, those who build kits, and those who design from scratch (that does not even describe all the types who read and post on these vacuum tube threads). It is a very good thing to have all of those persons, we all can learn something, and can have multiple ways to have amplifiers that we enjoy.
How rigid do we need to be in our particular expertise and philosophy of how to work on old amplifiers? Under the 100% Restore Only criteria, I wonder if anybody should use plastic coupling caps. Should they hunt for and use the old leaky Black Beauty caps that so often go leaky with age (or carefully remove the outer plastic from the Black Beauty and insert a new paper capacitor inside). And then they can replace the 'new'/restored almost Black Beauty paper capacitor after time when it goes leaky.
The Dyna Stereo 70 used a 2 wire non polarized power cord. There was no capacitor from either the neutral nor the hot wire to the chassis (and no way to tell which wire was which). There was no capacitor across the primary power switch. The only capacitance to the chassis was from the power transformer, filter choke, output transformers, and the ceramic capacitors connecting ground capacitively to the center taps of the two 6.3V filament secondaries.
By the way, the Dyna Stereo 70 was not ever a hot chassis (unless one of the transformers, chokes, or wiring shorted to the chassis). There are hot chassis, grounded chassis, and a 3rd class that is neither hot nor grounded.
I am sorry for the questions again, but here goes: If the Dyna Stereo 70 is restored to original, how often do I need to check the leakage currents to the chassis? And which way should I plug the 2 wire into a modern 3 wire outlet? Will the leakage current be the same for each way I plug it in?
All my other vacuum tube amplifiers started life with similar 2 wire power cords. They are now modified for 3 wire power cords. They also did not, and still do not have any capacitor connected to the chassis. and there is no resistor connected from hot, neutral, or power ground to the chassis. the chassis is connected directly to the power ground, and inputs and outputs are connected by wire to the chassis.
Since my house, and other places I take old amplifiers to have 3 wire grounded outlets, I think it is safer to have the chassis of a Dyna ST70 grounded. And that goes for many other amplifiers with old transformers. Of course any capacitive currents from power transformer are conducted to ground (and yes, could potentially create a ground loop).
As I said, I have even seen a brand new transformer shorted from primary to secondary, and a brand new transformer shorted from primary to laminations. And then there are the other transformers that have shorted after decades of good service.
For me, safety first. Ground loops second. I will cross the ground loop bridge when I get one that needs fixing.
One of the most dangerous places I worked was on board a US naval destroyer. "grounded" metal was everywhere (Power system 'ground'). And 110V was statistically the highest rate killer of sailers that died by electrocution.
There is probably some old equipment that nobody should be using without either special modification, or that now has a chassis or other exposed metal covered, or grounded. An electrocution of a person that used an old electric hand drill is an example of what not to do when working under a house on wet ground. That is why the new drills have to meet a new standard, double insulated that you mentioned.
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Hi 6A3sUMMER,
Look, I have a real problem with anyone who destroys equipment that could be returned to service. Audio equipment, test equipment. If something has no value to you, give it to someone who does see value in it. That's all. With the way you feel about old transformers, they don't hold any value to you, so just pass on equipment or funnel it to someone who cares.
-Chris
Well, I did say you should use modern components that were much more reliable. That stands as my opinion on the subject.
... and was one of the least expensive kits you could buy in wide distribution. They aren't even good amplifiers compared to what else was out in the market back then. I'm surprised they neglected the capacitive coupling to the AC mains. Not surprised they didn't protect the power switch. I've rebuilt many, but without the satisfaction that comes from bringing a nice amplifier back into the living world.
Okay, but this isn't always true in my area where there are many old houses with audiophiles living in them. It is unusual to have a transformer short, but I have seen it a few times. I repair what is placed in front of me, whether its an AA5 set or an older McIntosh, Fisher or whatever. I'm not going to force my opinion on someone who has been using a piece of equipment. I will insist on a new power cord if the old one is damaged, especially if the ground pin has been cut off. That is a clear case where the law leaves me no wriggle room.
Okay.
Or cheap new ones apparently. I've never had a defective new transformer, but I don't buy inexpensive transformers that leave the factory untested, as yours apparently did.
Don't buy cheap transformers. I buy Hammond or another good name brand part when I have to.
Rare, and those have usually been overheated at some point.
We aren't on a ship. Just thought I'd mention that.
No doubt. You should see what musicians do to each other. That would impress you.
Look, I have a real problem with anyone who destroys equipment that could be returned to service. Audio equipment, test equipment. If something has no value to you, give it to someone who does see value in it. That's all. With the way you feel about old transformers, they don't hold any value to you, so just pass on equipment or funnel it to someone who cares.
-Chris
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