Updating, not replacing, my older amp?

[Razz]

So I own a fantastic older ATI 1505. It's a solid and a very clean amp. Still runs perfectly and sounds amazing but it is very old. I don't even know how old actually. I want to keep it good to go in the future if and when I need it. I understand that some parts will degrade over time. Can I bring this in for replacement parts that will eventually fail???
Like replacing your tires?


rammis.. you there?

 

[Deleted member 133]

Not rammis here. Not even close. But...

I've had a number of (old) amps into the shop over the years - once or twice because something was definitely wrong, but mostly just to make sure everything's ok - and they never had a problem with parts. Mostly NAD, and ("conventional") Carver, and Phase Linear, maybe SAE, and... usually change a few transistors or what have you, adjust a few things, and you're good for another 20 years.

Jeff

 

[heeman]

If the amp is not powered on from time to time, the risk is that the Electrolytic Capacitors could dry out. Main concerning is the main filtering (bulk) caps in the front end of the power supply. Other filtering caps are suspect to dry up as well.

But, our resident expert must chime in.........

 

[Randy]

I have an old Pioneer M25 (I think) that hasn't been used in years that I fear I may have this issue with if I ever decide to fire it up.

My ATI 1505 gets used enough that I don't worry so much about it.

@Razz I think the shipping getting that thing back and forth to the service center may be more than the service itself. LOL. ATI= amplifier beast mode!

 

[Razz]

@Razz I think the shipping getting that thing back and forth to the service center may be more than the service itself. LOL. ATI= amplifier beast mode!

ATI=TRUE BEAST
Luckily it's just a 40 min road trip. I've been there twice now. Last time I just showed up there they sent me in the back and I met the owner, then after 5 mins I realized rammis was sitting in an office right next to me. He gave me the cool kids tour! Sorry Jeff, you're not on that list.

 

[MakeMineVinyl]

Aside from occasionally checking / adjusting the bias on the output transistors, there is really no maintenance to do on a power amp. Semiconductors, including transistors, diodes, and ICs do not wear out unless there is a problem elsewhere in the circuit which presents them with voltages/conditions outside of their design limits. Other components like resistors and non-electrolytic capacitors also do not wear out.

Electrolytic capacitors can dry out and loose their capacity to be a capacitor after a couple to several decades depending on how the amplifier was used. If the amplifier was always kept in a well ventilated area away from excess heat and never abused, these capacitors can last many decades - I have amplifiers which I bought in the early 1970s and one before that which have never had an electrolytic capacitor go bad or degrade. If the amplifier is in an enclosed space where the heat can get really high (to where it is uncomfortable to keep your fingers on the heatsinks), then the life of the capacitors can be shortened <= 15 years or so. ATI typically uses capacitors rated for 105 degrees C verses the 85 degrees C rating commonly used. This means that they will last much longer in a hotter environment (like next to heatsinks).

Your ATI 1505 amp is probably 10-15 years old, just like my ATI 1504. It is good practice to plug in and run any unused or little used amplifier (or any other electronic component) for about half an hour or so approximately once or twice a year to make sure that the main smoothing capacitors stay fully formed.

The thing is, even assuming we here at the factory had replacement capacitors still in stock for the main DC smoothing storage capacitors, they also would be 10-15 years old and during that time would have never seen any use. If these capacitors ever need replacement, they should be purchased from fresh stock (assuming they are even made anymore) from sources like Digikey. Likewise, semiconductors have a remarkably short manufacturing lifetime; ironically it is much, much easier to find brand new vacuum tubes which are still being manufactured for audio designs from the 1930s and 1940s, like the 300B tube!

Potentiometers (volume controls and other pots) can and do get noisy over time. Sometimes this is due to DC leakage from an upstream DC blocking capacitor causing the carbon track on the pot to degrade; it is seldom just "dirt" on the track. Squirting "contact cleaner" inside a potentiometer is not a fix! For one thing, contact cleaner is meant for metal-to-metal contacts, and a potentiometer has one metal contact and the other is the carbon track. Contact cleaner will over time cause the carbon track to turn to goo and the situation will ultimately become worse. In any event, any quieting action of applying contact cleaner will be short lived, and the noise will just come back. The real fix is to replace the potentiometer and any upstream capacitors which have become leaky.

Another potential source of intermittent noise is the contacts sometimes used to plug one circuit board into another. These can get corroded over time if they are made from any other material than gold. The worst possible environment for an amplifier is in a room where somebody smokes; there will be thick deposits of crud on all the exposed contacts and other surfaces (not to mention the person's lungs). ATI typically does not use contacts like these to connect together circuit boards.

Bias current adjustments are not really needed unless the amplifier gets overly hot with no signal (uncomfortable to touch with your fingers). If the amp is getting overly hot (again, with no signal), it could be either a bias adjustment or could be some other component causing the bias current to become excessive. At the other extreme of no or very little bias current, crossover distortion will start to become a factor. You will seldom actually hear distortion from this source with most program material. If you feed a very low frequency like <100Hz at low level, you might hear a "raspy" quality riding on the low frequency tone which is most likely due to crossover distortion.

You can bring the amplifier down to the factory to be checked if you want (or if you simply want to visit beautiful downtown Montebello.....), but I would think you would get more benefit by just powering up the amp once or twice a year and calling it good.

 

[Randy]

Don't want to hijack Razz's original thread, but @rammisframmis I think we discussed this before but I have no idea where, did a search and netted no results.

So the Pioneer M25 I have laying around hasn't been used in years, is there anything I should do before trying it out?

 

[MakeMineVinyl]

Don't want to hijack Razz's original thread, but @rammisframmis I think we discussed this before but I have no idea where, did a search and netted no results.

So the Pioneer M25 I have laying around hasn't been used in years, is there anything I should do before trying it out?

For gear which has not been used in a decade or more, it is advisable to use a variac to gradually bring up the AC line voltage to the amp. However generally if it hasn't that long, you can just plug it in and turn it on; if the capacitors are on their way out, you'll sure know it soon enough.

I should note that any component which has digital processing components like any modern preamp, using a variac to bring up the AC line will play havoc with the booting procedure of the digital ICs, and the component might not function.

 

[heeman]

Don't want to hijack Razz's original thread, but @rammisframmis I think we discussed this before but I have no idea where, did a search and netted no results.

So the Pioneer M25 I have laying around hasn't been used in years, is there anything I should do before trying it out?

Throw it out and look forward!

 

[Randy]

For gear which has not been used in a decade or more, it is advisable to use a variac to gradually bring up the AC line voltage to the amp. However generally if it hasn't that long, you can just plug it in and turn it on; if the capacitors are on their way out, you'll sure know it soon enough.

I should note that any component which has digital processing components like any modern preamp, using a variac to bring up the AC line will play havoc with the booting procedure of the digital ICs, and the component might not function.

Yup, that was it. Now that you repeated it I remember that was what you told me before.

Thank you so much sir. Any idea where I can find one of these variac tings?

Throw it out and look forward!

Umm, it is a classic amplifier in what appears to be pristine condition (if it works that is), I hardly think I will throw it out.

 

[MakeMineVinyl]

Just Google "variac" and you will get several options on buying one. There are several power options, and you can get a 500 watt one for about $60.

 

[Deleted member 133]

Throw it out and look forward!

Isn't it time for that C4 upgrade?

 

[heeman]

I have an itch.....................

But very satisfied with what I have now, however there are improvements that can be made.

 

[Razz]

good stuff @rammisframmis thanks!
Sometimes I question why I keep my 1505 as I've replaced it with a 2007, but I just can't seam to let it go. It was such a nice upgrade coming from my old Denon 3806

 

[MatthewB]

Russ you ever want to toss that ancient amp away. I'm one state away and I'll pay for shipping.