So i have 2 of these old peecker sound TVA 1800 amps. Bought back in 1997, have been used till 2002. and then they sat in a warehouse untill 2013 when i put them back to use again.
When i have been restoring them i did not much other then a decent dust cleanup and replacing the power on/off switches.
Since then they have done about 20 parties and a few live shows, they have mostly been pushing 4 18inch 8ohm drivers and a few times some rcf event 6000 boxes (so 4 ohm loads). Never had a problem, they work perfect, sound nice and since i had a chance to compare... they wipe the floor with a 6 year old yamahas p7000s when talking about subs.
However, they are 18 years old, all the small capacitors in the amp seem just fine, no bloating, no leaking. But the main 4 power supply capacitors are kendeil 22000uf 120V capacitors and i can se really small dried up leaks on top of them. They are not bloated or something similar, but are probably going to reach the end of their lifetime in near future.
No i will post some pictures and ask, if i want to recap my amp, would that include replacing all the small capacitors that exist in the entire amplifier or would that mean replacing just the main 4 big power supply capacitors?
How can i test if the capacitors are in bad condition and need a replacement?
The amps do work really fine, but should i expect event more power after replacing these 18 year old capacitors?
Here are some pictures of the amp and the big capacitors:
http://i30.photobucket.com/albums/c316/athlon-64/IMG_2486_zpstbnxhx8d.jpg
http://i30.photobucket.com/albums/c316/athlon-64/IMG_2507_zpsmc56iglm.jpg
http://i30.photobucket.com/albums/c316/athlon-64/IMG_2512_zpsw4al51u1.jpg
http://i30.photobucket.com/albums/c316/athlon-64/IMG_2518_zpszmmz3fsg.jpg
http://i30.photobucket.com/albums/c316/athlon-64/IMG_2485_zpsnvbfwtdh.jpg
When i have been restoring them i did not much other then a decent dust cleanup and replacing the power on/off switches.
Since then they have done about 20 parties and a few live shows, they have mostly been pushing 4 18inch 8ohm drivers and a few times some rcf event 6000 boxes (so 4 ohm loads). Never had a problem, they work perfect, sound nice and since i had a chance to compare... they wipe the floor with a 6 year old yamahas p7000s when talking about subs.
However, they are 18 years old, all the small capacitors in the amp seem just fine, no bloating, no leaking. But the main 4 power supply capacitors are kendeil 22000uf 120V capacitors and i can se really small dried up leaks on top of them. They are not bloated or something similar, but are probably going to reach the end of their lifetime in near future.
No i will post some pictures and ask, if i want to recap my amp, would that include replacing all the small capacitors that exist in the entire amplifier or would that mean replacing just the main 4 big power supply capacitors?
How can i test if the capacitors are in bad condition and need a replacement?
The amps do work really fine, but should i expect event more power after replacing these 18 year old capacitors?
Here are some pictures of the amp and the big capacitors:
http://i30.photobucket.com/albums/c316/athlon-64/IMG_2486_zpstbnxhx8d.jpg
http://i30.photobucket.com/albums/c316/athlon-64/IMG_2507_zpsmc56iglm.jpg
http://i30.photobucket.com/albums/c316/athlon-64/IMG_2512_zpsw4al51u1.jpg
http://i30.photobucket.com/albums/c316/athlon-64/IMG_2518_zpszmmz3fsg.jpg
http://i30.photobucket.com/albums/c316/athlon-64/IMG_2485_zpsnvbfwtdh.jpg
You could measure the ripple voltage when the amp is working quite gently and compare that to when working really hard.
I would expect the ripple to increase significantly when working hard.
But I have no guideline figures for you.
Maybe some more experienced PA operators could advise.
Worn out or heat damaged capacitor/s will perform worse.
I would expect the ripple to increase significantly when working hard.
But I have no guideline figures for you.
Maybe some more experienced PA operators could advise.
Worn out or heat damaged capacitor/s will perform worse.
E-caps can and do dry out and lose function. On the other hand, caps are much better in recent history than they were say in the 1960s. But think of it this way, if you install a 5-year battery in your car, and after 5 years it still starts the car reliably every time, would you replace the battery anyway just because of its age?
If the amp is working well, and seems not to suffer, why not allow the caps to age gracefully? I regularly see old Peavey CS800 amps of 30-35 years of age, and the similar can caps in those are still working great.
If the amp is working well, and seems not to suffer, why not allow the caps to age gracefully? I regularly see old Peavey CS800 amps of 30-35 years of age, and the similar can caps in those are still working great.
I understand. I mean it's not a huge problem replacing them but 22000uf 120v caps are not exactly cheap.
I will do some testings in order to check their condition.
There is no fear of sudden capacitor explosion or similar things? Since they have not event started to get bloated. There are just some dried out sticky leaks on top of them.
I will do some testings in order to check their condition.
There is no fear of sudden capacitor explosion or similar things? Since they have not event started to get bloated. There are just some dried out sticky leaks on top of them.
Computer grade caps won't get bloated. They are heavily potted inside with a little air space at the top. If they do vent it will be through the rubber seal at the top - and you'll know about it. A little "dried out sticky stuff" on the top may have come from the environment. All kinds of crap gets inside these amplifiers - look at all the dust. Most of the time they just dry out and lose capacity and when that happens the P7000's will stomp them. Right now I'd guess the caps are good.
wrong analogy.
If the battery is critical to operation, then a good designer will determine what worst case life one would expect from a well maintained battery and design into the maintenance documentation when to replace the battery. That's why very few planes fall out of the sky.
If the component is not life critical, one can choose to carry on using the equipment until a component fails and destroys the remainder beyond repair.
Well i agree with "if it works well dont fix it" but i could get more out of those amps i would invest in new capacitors. However i probably can"t and they won"t detonate just because they are old so i think it"s best simply keeping them while they work great. I will do some testings to see their condition and then write here again. First they have a techno party to run this saturday
Andrew, then please propose a better analogy that suggests we don't automatically replace something because of the calendar, that being my point. In my humble experience, filter caps mostly just dry out and perform less and less. They don't usually fail in a manner that does damage to the rest of the circuit. The amp will get hummy, not smoky.
In fact, my wife's car started first time, every time with its battery for 12 years. I finally replaced that battery a couple weeks ago because it finally started showing signs of weakness. Had I replaced it at the end of calendar life, I would have discarded seven years of service. That is why that battery analogy came to mind.
In fact, my wife's car started first time, every time with its battery for 12 years. I finally replaced that battery a couple weeks ago because it finally started showing signs of weakness. Had I replaced it at the end of calendar life, I would have discarded seven years of service. That is why that battery analogy came to mind.
I gave some information on alternatives to doing nothing until failure happens.
Use some thought and follow a sensible maintenance regime.
Using your battery:
ask your servicer to check the battery at each service. Tools that report on battery health have been available for more than half a century.
Don't wait till a "critical to operation" item fails.
decide what the risks are.
decide what options are available to mitigate the risks.
Amplifier capacitor:
what happens if the capacitor fails?
Is that failure critical to operation/repair?
are others critically dependent on a "no failure" outcome?
Is letting the capacitor fail acceptable, or would a maintenance regime to more suitable?
Think about it, don't just do nothing.
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You forgot:
A maintenance routine may well kill your amplifier - "if it ain't broke don't try and fix it"
However, there are certain problems, in certain items, that would certainly benefit from a regular replacement schedule - but randomly replacing capacitors on items that don't fall in that category is probably a poor idea.
I've done a LOT of preventative maintenance over the years, on TV's VCR's etc. - but that's based on knowing EXACTLY what tends to fail, and if it's not been replaced recently, then replace it while you've got it apart.
With capacitors of that size and cost being used professionally, it might be useful to invest in an ESR capacitance meter like the Peak esr70: Peak Capacitance and Equivalent Series Resistance Meter | ESR70 | Peak
Then you can also check the little caps.
The consumer grade gear I work on, the e-caps are trash by 15-20 years. Computer parts and TV remotes, they have special caps that fail in 1 to 5 years. All this talk of modern caps being automatically good - I could show you a horror show from modern consumer grade gear.
There are 10000 hour e-caps, there are 500 hour e-caps, the vendors will sell what the manufacturer wants.
For specs on ESR of your caps, look at new ones. Old ones drying out go high ESR.
When an amp has hum, low power into resistor load, frequency response is not flat, I replace all the e-caps. Life is too short to spend it taking the case off over and over again, IMHO. Power is (v^2)/R where v is measured by an analog meter, not a DVM. DVM make random numbers on music in my experience, except perhaps the Fluke RMS capable models, and those don't go above 5000 hz according to spec. Analog meters will read RF oscillation as power if you have that problem. R is the load impedance.
Then you can also check the little caps.
The consumer grade gear I work on, the e-caps are trash by 15-20 years. Computer parts and TV remotes, they have special caps that fail in 1 to 5 years. All this talk of modern caps being automatically good - I could show you a horror show from modern consumer grade gear.
There are 10000 hour e-caps, there are 500 hour e-caps, the vendors will sell what the manufacturer wants.
For specs on ESR of your caps, look at new ones. Old ones drying out go high ESR.
When an amp has hum, low power into resistor load, frequency response is not flat, I replace all the e-caps. Life is too short to spend it taking the case off over and over again, IMHO. Power is (v^2)/R where v is measured by an analog meter, not a DVM. DVM make random numbers on music in my experience, except perhaps the Fluke RMS capable models, and those don't go above 5000 hz according to spec. Analog meters will read RF oscillation as power if you have that problem. R is the load impedance.
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You don't need any special equipment. Test the amp for power at 20 Hz. If the big caps are good it will still put out full power. That is, whatever rated FTC 20-20k is. If it puts out less power than it used to, they are losing capacity. That may take decades.
The little PCB mounted caps don't last anywhere near as long as the big cans do. At lower temps than 85C and lower ripple currents than full rated they will last many times their "rated" life. Big amps of yesteryear using those big can caps lasted decades. The push in more recent years to use cheap PCB mount caps (which have lower rated ripple currents and cannot dissipate heat as effectively) result in amps that need recapping a whole lot sooner.
The little PCB mounted caps don't last anywhere near as long as the big cans do. At lower temps than 85C and lower ripple currents than full rated they will last many times their "rated" life. Big amps of yesteryear using those big can caps lasted decades. The push in more recent years to use cheap PCB mount caps (which have lower rated ripple currents and cannot dissipate heat as effectively) result in amps that need recapping a whole lot sooner.
Yes well, these big caps, in the position they have in the amp, don't get any warm air near them. They are in a dead cold section of the amp. The other side witch is separated by a metal plate has got power modules that get hot.
Also, you think my bigger concern should be the small capacitors on the PCB of power modules?
Electrolytic caps only are failure prone. Pressure seals can be gum rubber (short life) or silicon or epoxy (long life)
Since about 1967, film caps have been extremely reliable. Learn to read the difference. Electrolytics have a plus on one end, a minus in balls pointing at one lead, or the letters "NP" after the voltage rating for non-polar ones.
Disc caps (ceramic) have been reliable since WWII if the paint completely covered the metal. Variable, but reliable.
I've seen a number of DVM produce random numbers on music. Come behind my organ & I'll show you on the reverb output jack.
I don't have a radio (signal source) that produces 20 hz; too many pros with lots of test gear are responding . A $20 Radio Shack 5000 ohms/volt analog meter with a 50 v scale is perfect for measuring output power, but they don't sell them anymore. All that is available around here is $25 1000 ohms/volt analog meters sold in the auto repair department. That is probably better than a dvm. I use a Simpson 260-6XLPM meter for music readings but that was $187 in 1989. More like $280 now. Any music with constant volume is fine for power readings. My music includes 5000-15000 hz in addition to 20-5000 hz. I really don't see the point of buying a $180 flukemeter with digits that produce all 8's in your eyes when the volume changes. The pointer on an analog meter moves slowly up & down and can be followed. Scopes are nice but usually broken, in my experience. "PC scopes" don't have earth isolated ground - hence they are not safe for debugging possibly buggy amps in my book.
Since about 1967, film caps have been extremely reliable. Learn to read the difference. Electrolytics have a plus on one end, a minus in balls pointing at one lead, or the letters "NP" after the voltage rating for non-polar ones.
Disc caps (ceramic) have been reliable since WWII if the paint completely covered the metal. Variable, but reliable.
I've seen a number of DVM produce random numbers on music. Come behind my organ & I'll show you on the reverb output jack.
I don't have a radio (signal source) that produces 20 hz; too many pros with lots of test gear are responding . A $20 Radio Shack 5000 ohms/volt analog meter with a 50 v scale is perfect for measuring output power, but they don't sell them anymore. All that is available around here is $25 1000 ohms/volt analog meters sold in the auto repair department. That is probably better than a dvm. I use a Simpson 260-6XLPM meter for music readings but that was $187 in 1989. More like $280 now. Any music with constant volume is fine for power readings. My music includes 5000-15000 hz in addition to 20-5000 hz. I really don't see the point of buying a $180 flukemeter with digits that produce all 8's in your eyes when the volume changes. The pointer on an analog meter moves slowly up & down and can be followed. Scopes are nice but usually broken, in my experience. "PC scopes" don't have earth isolated ground - hence they are not safe for debugging possibly buggy amps in my book.
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My friend explained me that we can test them by seeing how high their resistance has got.
He told me that as they get older their resistance will rise witch will cause voltage drops for electricity getting trough them and will also couse them to get warmer and dry out even faster.
All 4 of them, when we put 10V trough them, caused only a 50mV voltage drop witch is normal and insignificant. Also when the amp is running they charge up to 107V.
He told me that as they get older their resistance will rise witch will cause voltage drops for electricity getting trough them and will also couse them to get warmer and dry out even faster.
All 4 of them, when we put 10V trough them, caused only a 50mV voltage drop witch is normal and insignificant. Also when the amp is running they charge up to 107V.
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