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Calling All Yamahas. Time to Post Your Pics

H.Huester said:
Minor detail: All worked well the last time I ran the C-4. I received my LEDs, pulled the case and front panel, and disconnected the bad bulb at the power switch. Plugged the unit back in to figure out which LED lead goes to the red & white wires, and I now have no power at any of the bulbs. I used to hear a relay click 3-5 seconds after I push the power switch - now I hear nothing. I cycled the power switch a number of times and checked for power at the switched outlets - all good. Checked the four fuses by the power transformer - all are good. What should I be looking for next?
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did you figure this out? Did you start a new thread? If yes, send me the link.

the short version is: If your power source for the light bulbs is somehow shared with the RC timer for the relay time delay, there might be an adjustment that needs to happen on the RC timer to account for the difference of current required for the LEDs vs the old incandescent bulbs. Typically you would just have a screwed up timing with maybe a pop in the speakers. But...it can get more complicated.
Start a new thread or send a link tot he one you have already opened...if you are still in need of help.
 
rottalpha said:
did you figure this out? Did you start a new thread? If yes, send me the link.

the short version is: If your power source for the light bulbs is somehow shared with the RC timer for the relay time delay, there might be an adjustment that needs to happen on the RC timer to account for the difference of current required for the LEDs vs the old incandescent bulbs. Typically you would just have a screwed up timing with maybe a pop in the speakers. But...it can get more complicated.
Start a new thread or send a link tot he one you have already opened...if you are still in need of help.
Click to expand...
H

Thread 'C-4 went south'

All worked yesterday - the last time I ran the C-4. I had a power button light burnt out - it's happened before and I planned to swap bulbs for LEDs. I pulled the case and front panel, and removed the bad bulb at the power switch. Plugged the unit back in to figure out which LED lead goes to the red & white wires, and I now have no power at any of the bulbs. I used to hear a relay click 3-5 seconds after I push the power switch - now I hear nothing. I cycled the power switch a number of times and checked for power at the switched outlets - all good. Checked the four fuses by the power...
 
rottalpha said:
did you figure this out? Did you start a new thread? If yes, send me the link.

the short version is: If your power source for the light bulbs is somehow shared with the RC timer for the relay time delay, there might be an adjustment that needs to happen on the RC timer to account for the difference of current required for the LEDs vs the old incandescent bulbs. Typically you would just have a screwed up timing with maybe a pop in the speakers. But...it can get more complicated.
Start a new thread or send a link tot he one you have already opened...if you are still in need of help.
Click to expand...
No, it quickly went beyond my skill set, or my desire to learn enough to address it myself. I swapped in a spare preamp to carry me through, and took the C-4 up to Denver for someone with a “particular set of skills” to troubleshoot & repair it.
 
H.Huester said:
No, it quickly went beyond my skill set, or my desire to learn enough to address it myself. I swapped in a spare preamp to carry me through, and took the C-4 up to Denver for someone with a “particular set of skills” to troubleshoot & repair it.
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I see. In most cases that is actually the optimal solutions. We ALL need to learn from you!

Let us know how when she comes back.
 
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Sparkplug said:
Nothing sounds like a B-2 …

The beast is back in service after some major overhaul. Also many thanks to @rottalpha for guidance during some sticky situations during final testing, everything is right on the money. :thumbsup:

Another major overhaul coming right up … :biggrin:

View attachment 3782555

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Glad to see another world class amp given another life.
One minor callout:
Did you set your DC offset with the fan ON or with the fan OFF ;)
 
rottalpha said:
Did you set your DC offset with the fan ON or with the fan OFF ;)
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Rudimentary Watson … that fan has never seen the inside of my lab. It’s an afterthought that works really well after all is done and dusted.

The biggest game changers for me have been using the LSK389a’s and the Nichicons, DC Offsets are rock solid. So much so that after sitting at zero mV for too long, I started wondering, is this thing working? Then suddenly there was a flicker of -0.1mV and back to 0 … :rflmao:
 
Sparkplug said:
Rudimentary Watson … that fan has never seen the inside of my lab. It’s an afterthought that works really well after all is done and dusted.

The biggest game changers for me have been using the LSK389a’s and the Nichicons, DC Offsets are rock solid. So much so that after sitting at zero mV for too long, I started wondering, is this thing working? Then suddenly there was a flicker of -0.1mV and back to 0 … :rflmao:
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that is how a single die, dual jfet rollz :biggrin:
 
808_state said:
I think I'm going to need some background info on the beastly dual power supply looking thing sitting beneath the tube/cathode looking thing. This is a deceptively understated (awesome) picture.
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I remember Nick talking about them before, some kind of High powered Tube amps or something .

I remember looking them up and they are highly regarded and $$$$

Athanasios
 
Nashou66 said:
I remember Nick talking about them before, some kind of High powered Tube amps or something .

I remember looking them up and they are highly regarded and $$$$

Athanasios
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Cool! I hope his local power company sends him a Christmas gift each year ; )

Seeing random awesome things like this and the continuous stream of beautiful Yamaha gear (my top and forever favorite) is why I keep coming back to this thread.
 
808_state said:
I think I'm going to need some background info on the beastly dual power supply looking thing
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Yes indeed and thanks for your interest. They're a pair of Krohn-Hite UF-101 ultra low distortion mono block amplifiers from the 1950's that I've enjoyed for years.
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They were lovingly restored and listened to, first through a pair of QUAD ESL-57's and then a pair of ESL-63"s that recently took a hissy fit. At that time I also had a wonderful pair of McIntosh MC-240's but I favoured the K-H's so the MC's moved on for someone else to enjoy. That being said, to my ears both were sonic masterpieces in their own right.

Sadly, these days the UF's don't get a lot of listening to since they played better with the ESL's than they do with the NS-1KM's and due to my love for my V-FET sonics so they'll be moving on soon too ...
sitting beneath the tube/cathode looking thing.
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Another rescued relic from the past.
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It's the Transmitter output tube from the first local AM radio station here back in the day. The filament still lights up but there's 0 trans conductance left in it. Hand made in the 1930's and still makes a nice shelf trophy and conversation piece.
This is a deceptively understated (awesome) picture.
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:)
Seeing random awesome things like this and the continuous stream of beautiful Yamaha gear (my top and forever favorite) is why I keep coming back to this thread.
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Understood and appreciated!
:thumbsup:
 
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So amidst a parts hunt for my CDX-2000 (currently at a standstill...), I happened upon this little CDX-500u. An auction site rescue in rough shape when I got it but appeared to be barely used. Repair guy went through it this week and he remarked about laughing to himself at how well the laser measured and how clean it was inside, just a bad ground lug on one of the outputs and a couple disintegrated belts. He cleaned it up and wow, it sounds fresh and beautiful, not fatiguing in any way. Still in love with the Yamaha sound!

IMG20260703144806.jpg

After this I've got a repaired CDX-900u to try out as well...
 
808_state said:
So amidst a parts hunt for my CDX-2000 (currently at a standstill...), I happened upon this little CDX-500u. An auction site rescue in rough shape when I got it but appeared to be barely used. Repair guy went through it this week and he remarked about laughing to himself at how well the laser measured and how clean it was inside, just a bad ground lug on one of the outputs and a couple disintegrated belts. He cleaned it up and wow, it sounds fresh and beautiful, not fatiguing in any way. Still in love with the Yamaha sound!

View attachment 3794453

After this I've got a repaired CDX-900u to try out as well...
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What an amazing phono preamp! I had the chance to listen to one, but I couldn't afford to buy it.
 
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