Reviving Vintage Audio

[walter duque]

I have (2) Threshold Stasis III Mono Blocks, (2) H&K Mono Blocks, (2) Sony Pre-Amps, (2) Sony Power amps, 1 VSP Steightwire Pre-Amp and (2) VSP Gold Edition Poweramps. Some of this equipment I have not used for 20-30 years. My question is how do I properly revive this equiment. I was told by a friend of mine not to plug it directly into 110 Volts, that I should use a Voltage Regulator and start off at 10 Volts and every day increase the Voltage by 10 till I hit 110 Volts to avoid blowing them. Is this correct?

 

[Alex2507]

I would just PM TLS Guy directly with an invitation to participate in this thread. It beats waiting for him to spot the thread. PENG would be another member to get a written invite.

 

[lsiberian]

I would just PM TLS Guy directly with an invitation to participate in this thread. It beats waiting for him to spot the thread. PENG would be another member to get a written invite.

I feel like I learn something every time TLS Guy posts.

 

[chris357]

the forum audiokarma seems to be really vintage oriented that might be another place to look aswell

 

[Alex2507]

I feel like I learn something every time TLS Guy posts.

Unlike when reading one of my posts, huh?
Even I get dumber after reading one of my posts.

 

[Adam]

Unlike when reading one of my posts, huh?
Even I get dumber after reading one of my posts.

I get a little bit more street smart when I read your posts. More book stupid, sure...but more street smart.

 

[adwilk]

street smart.

Sesame Street smart?

 

[adwilk]

Unlike when reading one of my posts, huh?
Even I get dumber after reading one of my posts.

To be completely honest, I have to look stuff up almost every time I read one of your posts.... Most of the time, I wish I hadn't.

 

[Alex2507]

I get a little bit more street smart when I read your posts. More book stupid, sure...but more street smart.

LOL! That's excellent.

To be completely honest, I have to look stuff up almost every time I read one of your posts.... Most of the time, I wish I hadn't.

You mean like why liberals are better than conservatives?

Seriously, thanks for the laughs.

Edit: Now quit thread jacking my new best friend's thread.

 

[audiofox]

I have (2) Threshold Stasis III Mono Blocks, (2) H&K Mono Blocks, (2) Sony Pre-Amps, (2) Sony Power amps, 1 VSP Steightwire Pre-Amp and (2) VSP Gold Edition Poweramps. Some of this equipment I have not used for 20-30 years. My question is how do I properly revive this equiment. I was told by a friend of mine not to plug it directly into 110 Volts, that I should use a Voltage Regulator and start off at 10 Volts and every day increase the Voltage by 10 till I hit 110 Volts to avoid blowing them. Is this correct?

A current surge (ie, inrush current), not high voltage, would be a more probable failure mode, which is also why most modern solid state power amplifiers (and receivers) have a built-in delay to prevent the surge from damaging the power supply (which will most likely fail before the failure affects the components on the DC side of the PS). A good visual inspection would definitely be in order if the units have not seen any power for 20-30 years. If your components have fuses, you could change them out during the inspection (along with any other obvious problems) to give yourself some extra insurance, but if there are old components in the power supply that are close to failing and are not visually suspect, no power-up scheme will prevent that from happening forever. If you get lucky the first time, you will just push the problem down the road so to speak, unless you never turn the unit off again! Also, if you have a brownout/blackout or other AC power issues, you will not be able to control the voltage ramp up/down, so it's better to just go for it and hope for the best.

 

[TLS Guy]

I just got back to Rochester Kent last evening after traveling from the Isle of Man. yesterday. I left the port of Douglas on the Ben-my-Chree at 8.45 Am yesterday, and docked at the port of Heysham, 9 miles west of Lancaster at 12.15 PM. I drove the 320 miles back to Rochester Kent. I got held up twice by accidents, as people don't know how to drive in big highways here. They drive far too close and traffic is dense everywhere 24 hours a day.

Anyhow, when firing up an old piece of equipment that has not been used for many years, you should fire it up on a Variac, which is the common brand of Variable voltage transformers that are made for the purpose..

You don't need to take days over it. I just advance it gradually, with the case open and instruments attached to make sure it comes up properly.

It can be dangerous to put the power on suddenly as smoothing caps can explode on old tube equipment and cause injury.

Slowly putting on the power will help the caps repolarize correctly. They often need changing though.

I will do some post on the the Isle of Man (Manx). I saw some fascinating stuff, including a guided tour of the Tinwald from my friend. I also documented the great wheel of Laxey (Lady Isabella). This is the largest water wheel in the world. Built in 1854. It develops 200 HP, and has what must be the worlds longest power take off to work a mine pump deep below the surface of the Earth. It still pumps 20,000 gallons of water every 8 hours so tourist can tour the old tin and copper mine. So renewable energy is nothing new!

 

[walter duque]

Thanks TLS GUY. I think I better take them do a shop and have them do it. Maybe I'll take one of the Sony's and just plug them in and see what happens. Now if something goes wrong is it possible that I get AC going to my speakers and destoy them?

 

[highfigh]

I have (2) Threshold Stasis III Mono Blocks, (2) H&K Mono Blocks, (2) Sony Pre-Amps, (2) Sony Power amps, 1 VSP Steightwire Pre-Amp and (2) VSP Gold Edition Poweramps. Some of this equipment I have not used for 20-30 years. My question is how do I properly revive this equiment. I was told by a friend of mine not to plug it directly into 110 Volts, that I should use a Voltage Regulator and start off at 10 Volts and every day increase the Voltage by 10 till I hit 110 Volts to avoid blowing them. Is this correct?

The slower ramp-up of voltage applies more to tube amps because the caps see much higher voltages, but the recommended starting point I have heard is closer to 60V and increase it by 10V/hour.

The first thing I would do is open them and do a visual inspection. If you see bulging caps or any signs of goo or crust at the base of a cap, replace the cap(s) before turning it on. Some of the caps may necessitate internal adjustments, too. Over time, some component values can change and it's important to make sure the bias and DC offset are correct.

Those amps were made after the voltage was increased to 120V, not 110V. Even mid-late '50s vintage schematics indicate 117V.

 

[highfigh]

Thanks TLS GUY. I think I better take them do a shop and have them do it. Maybe I'll take one of the Sony's and just plug them in and see what happens. Now if something goes wrong is it possible that I get AC going to my speakers and destoy them?

Possibly DC and yes, it would definitely destroy them if it's high enough, for a long enough time. I would turn the amp on with no speakers connected and use a multi-meter to measure across the speaker terminals for DC voltage. If it was a tube amp, it would need a normal load but since it's solid state, it doesn't.

 

[audiofox]

The slower ramp-up of voltage applies more to tube amps because the caps see much higher voltages, but the recommended starting point I have heard is closer to 60V and increase it by 10V/hour.

The first thing I would do is open them and do a visual inspection. If you see bulging caps or any signs of goo or crust at the base of a cap, replace the cap(s) before turning it on. Some of the caps may necessitate internal adjustments, too. Over time, some component values can change and it's important to make sure the bias and DC offset are correct.

Those amps were made after the voltage was increased to 120V, not 110V. Even mid-late '50s vintage schematics indicate 117V.

Agreed-power supplies in solid state electronics have step down transformers to reduce the voltage value, whereas tube power supplies do the opposite, since the tubes require higher (to much higher) voltages. That makes for a significant difference in the type of power supply capacitor used and their operating voltages (and their inherent failure risk). It's true that bipolar transistors may need their bias voltages tweaked, but that is unlikely to cause a failure, just unoptimized performance, since the cap value and power handling are pretty small.

 

[Rickster71]

I would set up the Variac in my office, because I didn't want to leave it unattended in the lab; and possibly set off the Halon.
I just didn't want to be 'that guy.'

I ended up replacing filters first. Old filter caps always seem to go bad; and twenty to thirty years old is up there for a cap. Even if their still sitting on a shelf.
The idea of pulling the cover and doing a visual, is a good idea.

 

[highfigh]

Agreed-power supplies in solid state electronics have step down transformers to reduce the voltage value, whereas tube power supplies do the opposite, since the tubes require higher (to much higher) voltages. That makes for a significant difference in the type of power supply capacitor used and their operating voltages (and their inherent failure risk). It's true that bipolar transistors may need their bias voltages tweaked, but that is unlikely to cause a failure, just unoptimized performance, since the cap value and power handling are pretty small.

Some of the tube stuff I usually deal with exceeds 500VDC, so those definitely qualify for using a Variac or light bulb-type current limiter, although the latter drops the voltage quite a bit without any adjustability.

Re: bias being wrong and transistors not a likely cause of failure- look into the R series of receivers from Sansui. They blew up so often/easily it was incredible. We used to joke that they put the output transistors in to protect the fuses. Their failures were due to the bias being too hot. We usually backed it off and really never saw them come back, other than when someone would short the speaker wires.