For you tube amplifer guys Fisher 200!

[bmw2800cs]

Ending about 10 years ago I used to go to garage sales looking for old tube amplifiers. Once in a while someone would say they have something stowed away and they would call me if they found it, I would give them my phone number. Well from a garage sale in 2009 someone called me yesterday, he wanted to get rid of something because he was moving. I guess I have a new project Massive transformers, bigger than any Mcintosh that I've ever seen!

 

[Stevehose]

Very cool, bring it to someone with a variac so you don't blow it up when plugging it in. Likely needing a re-cap and resistors check/replacement. Does he have another hiding away? Does it have original EL-34 power tubes? As you probably know, the stenciling on these comes off very easily so clean with nothing more than a slightly damp cloth. Pics of the tubes sans cage?

 

[bmw2800cs]

Very cool, bring it to someone with a variac so you don't blow it up when plugging it in. Likely needing a re-cap and resistors check/replacement. Does he have another hiding away? Does it have original EL-34 power tubes? As you probably know, the stenciling on these comes off very easily so clean with nothing more than a slightly damp cloth. Pics of the tubes sans cage?

Thanks Steve! I have a variac - I'll bring it up over about 4 days - does that sound like the right amount of time? I've had good luck with capacitors/resistors when I use the variac. I'll check on the El34's and take a pic without the cage! No other units hiding. I have a pair of heathkit wm-5's, pair of Ampex 621's. I used to have a HK Citation V.

 

[bluecoupe30!]

Looks like a new rabbit hole. We all seem to find such things....

 

[bmw2800cs]

Looks like a new rabbit hole. We all seem to find such things....

It's surprising, I've found a lot of old iron - st70's, Citation 5, assorted Fisher and lesser brand tube receivers, pre-amps, tuners. MOST of them after being brought up on the variac just worked.

 

[deQuincey]

It's surprising, I've found a lot of old iron - st70's, Citation 5, assorted Fisher and lesser brand tube receivers, pre-amps, tuners. MOST of them after being brought up on the variac just worked.

i beg your pardon, what is a variac ?

Nice fish !

 

[bmw2800cs]

i beg your pardon, what is a variac ?

Nice fish !

It's a variable transformer. I only know the basics:
These old amplifiers have electrolitic capacitors, if the amp isn't turned on for an extended period of time they become fragile. The variac has a 110 wall socket on it, you plug the amp into the variac and you slowly (over many days) run current through the amp. Starting at a very low voltage (I start at about 10 volts) and progressively over many days bring it up to 110 (I do 10 volt increments).

 

[deQuincey]

It's a variable transformer. I only know the basics:
These old amplifiers have electrolitic capacitors, if the amp isn't turned on for an extended period of time they become fragile. The variac has a 110 wall socket on it, you plug the amp into the variac and you slowly (over many days) run current through the amp. Starting at a very low voltage (I start at about 10 volts) and progressively over many days bring it up to 110 (I do 10 volt increments).

oooohhh

that is super sexy

i heard about dead capacitors, never heard about the cure

question is , once you do the variac "cure", are the capacitors good enough for normal use ?

is there any turn-off time lapse known for capacitors to say that they have become dead ? or even fragile ?

 

[bmw2800cs]

oooohhh

that is super sexy

i heard about dead capacitors, never heard about the cure

question is , once you do the variac "cure", are the capacitors good enough for normal use ?

is there any turn-off time lapse known for capacitors to say that they have become dead ? or even fragile ?

Since I haven't ever replaced the caps on an amp/preamp/tuner I'm extra careful (wouldn't know how to do it). If it was my amp and I hadn't used it for say 2 years I'd bring it up. Maybe someone else can comment. If I brought something up over 4 days I'd treat it as it was good enough for normal use. If the caps failed I'd assume they were too far gone.

If anyone else can correct any of my responses, feel free. I'm not an expert, I've replaced tubes and brought them up - that's all

 

[deQuincey]

Since I haven't ever replaced the caps on an amp/preamp/tuner I'm extra careful (wouldn't know how to do it). If it was my amp and I hadn't used it for say 2 years I'd bring it up. Maybe someone else can comment. If I brought something up over 4 days I'd treat it as it was good enough for normal use. If the caps failed I'd assume they were too far gone.

If anyone else can correct any of my responses, feel free. I'm not an expert, I've replaced tubes and brought them up - that's all

thank you

replaced tubes ?
dont you need to set bias ?

 

[bmw2800cs]

thank you

replaced tubes ?
dont you need to set bias ?

I've replaced a few tubes, one amp a Citation V I replaced all the tubes - these are hifi amps. It sounds like you know a lot more than me I have never set the bias. I'll have a look at the video, thanks!

 

[Stevehose]

Vintage capacitors will fail after time regardless if they have been used or not. So even if you find an NOS vintage amp and plan to use it, it should have the capacitors and resistors changed. If a certain capacitor or resistor fails then bye-bye to the irreplaceable transformer. Yes it can also affect bias but that will just blow up a tube (also a problem if it's a rare tube) if a resistor leaks. Not to mention tone is affected by out of spec components.

 

[Sean Haas]

Audio shop near me has a collection of this stuff (Mc, Fisher, etc.) on the shelf but just for display. Curious, how do these sound?

 

[Stevehose]

To me they sound “warm” which is very relaxing as I don’t listen to music loud anymore. Think classical, jazz, and Sinatra. They are not audiophile level by today’s standards but of course were back in the day. The build quality was military worthy as were the components. The knobs are very heavy and satisfying to use. The romance includes the visual of the tubes glowing and the fragrance of 1950’s and 60’s heated components filling the room. I am into the vintage stuff because they evoke a bygone era, much like our coupes do.

 

[bmw2800cs]

To me they sound “warm” which is very relaxing as I don’t listen to music loud anymore. Think classical, jazz, and Sinatra. They are not audiophile level by today’s standards but of course were back in the day. The build quality was military worthy as were the components. The knobs are very heavy and satisfying to use. The romance includes the visual of the tubes glowing and the fragrance of 1950’s and 60’s heated components filling the room. I am into the vintage stuff because they evoke a bygone era, much like our coupes do.

Agree with all of it and to add to it even in the 80s when my hearing was quite good and I would spend hours in audio shops with compo ends including Mark Levinson, Naim, Willson Audio Watt etc I found high quality vintage
tube amps with good speakers very satisfying. Maybe a pair of mc-30s with spica tc-50s.

 

[Sean Haas]

Kind of what I figured. I can appreciate that - was always intrigued by some of those audio show demos where they fire up the old western electric giant horn speaker setups with NOS tube amps. I've seen a couple people run those Disney Fantasia theater systems which was a rack of tube amps running the first multi-channel surround type system. Cool what people came up with using fairly limited tech. http://www.widescreenmuseum.com/sound/fantasound1.htm

 

[Ohmess]

Vintage capacitors will fail after time regardless if they have been used or not. So even if you find an NOS vintage amp and plan to use it, it should have the capacitors and resistors changed. If a certain capacitor or resistor fails then bye-bye to the irreplaceable transformer. Yes it can also affect bias but that will just blow up a tube (also a problem if it's a rare tube) if a resistor leaks. Not to mention tone is affected by out of spec components.

I did numerous replacement capacitors and resistors on the Electohome projector I used to have hanging from the ceiling in my basement. New Japanese capacitors made a huge difference. Its delicate soldering, but not hard.

 

[bmw2800cs]

I did numerous replacement capacitors and resistors on the Electohome projector I used to have hanging from the ceiling in my basement. New Japanese capacitors made a huge difference. Its delicate soldering, but not hard.

How do you know which replacement capacitor to buy. i assume there are markings on the old ones or do you find a schematic?

 

[Stevehose]

How do you know which replacement capacitor to buy. i assume there are markings on the old ones or do you find a schematic?

Both. Just match the type and voltage rating (or higher), there are various pice/quality levels of parts. If you post on Audiokarma the experts there will tell you exactly what to buy and where.

 

[Ohmess]

How do you know which replacement capacitor to buy. i assume there are markings on the old ones or do you find a schematic?

There are specifications on the capacitors. See here: https://www.engineering.com/story/how-to-interpret-capacitor-markings.

And when stumped, I could consult the folks at AVForums.

That said, I also added as an overlay country of manufacture. I found much better quality in the Japanese capacitors. Purchases were from one of three places: Mouser, Newark or Digikey.