Pioneer SA-500/TX-500 Project

[F1nut]

What do you do with some old gear you forgot you had? Restore and upgrade it, of course.

Neither the SA-500 or TX-500 had been used in a very long time and after powering up I could hear they were in need of work. Checking a few caps I found them way out of tolerance, so I replaced all the caps in both using a selection of Elna Silmic and Cerafine. One of the emitter resistors in the SA-500 was cracking, so all 4 were replaced. Some of the semi-conductors needed replacing in both as well. Of course, most of the pots were dirty, so they all got a good cleaning. Things were sounding better now. Intrigued, I decided to make a few upgrades, which I'll just list.

* Replaced the very odd stock binding posts with new 5 ways using black FR4 as a mounting plate.
* Replaced the stock power cords with shielded 16 gauge as there was no room to mount an IEC on either piece.
* Applied Dynamat Extreme to the top and bottom covers.
* Removed the SA-500 speaker On/Off switch from the circuit, making a direct connection from the amp board to the outputs with upgraded wire.
* Upgraded the wire between the pre amp board and the amp board.
* Removed the connections to the switched/unswitched outlets.
* Replaced all the RCA jacks with gold plated copper versions and spaced them further apart to allow the use of modern day interconnects. Again, I used black FR4 as the mounting plates.
* Replaced the SA-500 power light with a diffused blue LED.
* Replaced the TX-500 dial lights with diffused white LED's and the FM Stereo light with a diffused blue LED. Since the tuning meter is an off white plastic, clear blue LED's were used to back light it resulting in a diffused appearance, which matches well with the other blue diffused LED's.

I'm still toying with the idea of replacing the volume control with a motorized version allowing remote control, but since these have ended up in a guest bedroom, we'll see about that.

Thanks to Don (will make just about any LED you want, contact at deh12110@yahoo.com) for his help with the LED's and to Mark for his help with the semi-conductors. Those were two areas I had limited knowledge of, but have learned a lot more about both since I started this project.

I have to say for a little 10wpc integrated amp it sounds a lot better than I ever thought it could, has a kind of tube amp sound....nice! The tuner isn't bad either

Pic 1 - the original RCA's and power cord, I already upgraded the binding posts.
Pic 2 - view of the upgraded RCA's and power cords.
Pic 3 - close up of the new RCA's and mounting board.
Pic 4 - the original lights.
Pic 5 - with the new lights....ah, much better.

 

[Noodle]

:tresbon:

 

[F1nut]

Following up on this project. I've made some more modifications including adding remote controlled volume, a larger filter cap and better binding posts to the SA-500 with new feet and IEC's on both pieces.

I love having remote controlled volume now.

 

[jemilroy]

IMPRESSIVE! you turned old into new. Not sure if I will go that far..bought a Pioneer TX500a cheap when I started getting into vintage 2 years ago...($15)..thought "i'll easily find it's match..in Omaha"..no lights so opened it up and saw fuses WTF?. 2 years later found a SX 500a..lots of experience and am restoring..(including new lamps!).Nothing feels as good as giving new life..new sound to something from our past...that I could not afford.
Again..beyond impressive rebuild..dynamax..is that for sound and heat protection? Does it make a difference? (never used).

 

[F1nut]

IMPRESSIVE! you turned old into new. Not sure if I will go that far..bought a Pioneer TX500a cheap when I started getting into vintage 2 years ago...($15)..thought "i'll easily find it's match..in Omaha"..no lights so opened it up and saw fuses WTF?. 2 years later found a SX 500a..lots of experience and am restoring..(including new lamps!).Nothing feels as good as giving new life..new sound to something from our past...that I could not afford.
Again..beyond impressive rebuild..dynamax..is that for sound and heat protection? Does it make a difference? (never used).

Looking good. I see you changed the SA-500A's power light to a blue one like I did. It's much better than the original yellow/orange.

The Dynamat Xtreme is a damping material, it's not for heat protection.

 

[JKirkpatrick]

Beautiful work

 

[F1nut]

Thank you, sir.

 

[alexbau]

Following up on this project. I've made some more modifications including adding remote controlled volume, a larger filter cap and better binding posts to the SA-500 with new feet and IEC's on both pieces.

I love having remote controlled volume now.


View attachment 856995
View attachment 856999
View attachment 857002

Hi F1nut, what kind of light (LED or similar) shoul I search to change my dead light on my SA500a? Thanks in advance!

- Alex

 

[F1nut]

He'll get you set up.

https://sites.google.com/site/dgwojocom/

 

[alexbau]

He'll get you set up.

https://sites.google.com/site/dgwojocom/

Thank you very much!! I'm going to write him. I'll let you know. thanks again.

- Alex

 

[madders]

Wow looks really impressive!

When you changed the power cable to the kettle plug socket, did you ground the earth pin?

Do you have any more details about how you did the volume control? Suprised there's not more people doing this. Is it infrared?

 

[F1nut]

Wow looks really impressive!

When you changed the power cable to the kettle plug socket, did you ground the earth pin?

Do you have any more details about how you did the volume control? Suprised there's not more people doing this. Is it infrared?

Thank you.

I'm fairly certain I did not because the original wasn't. The Furutech IEC socket is only available with the ground pin, which is why you see it.

That's a long story that almost didn't happen due to trouble finding a power source for it. The remote controlled volume pot was obtained from Bent Audio and came with the eye and remote. The original Pioneer pot is a split volume/balance control and I wanted to retain the balance control, which in retrospect I shouldn't have because I never use it. Anyway, in order to make this all work I had to tap into the back of the original pot shaft then Loctite a threaded stud into it. This allowed me to use a shaft extension between it and the location of the new motorized pot. You see, I'm only using the motor to turn the shaft, which in turn moves the original pot. The power for the motor would have been simple if I could have tapped off the amp power, but the voltages were not even close, so I found a step down converter small enough to mount inside, but the ones I tried were junk and didn't work. Reluctantly, I had to use an outboard brick power source, which in the long run worked out better because it's completely out of any internal circuit.

Yes, it is infared. The eye is located where the mute button used to be. No loss there as it was a piece of junk.

That's the short version.

BTW, if anyone needs some custom heavy duty "L" bracket volume pot mounts I have plenty of extras, which are way better than anything you can buy on the open market.

 

[madders]

Hi F1nut, thanks for replying. It's very interesting.

I wonder if it's any safer to have the chassis ground connected to the house earth? I was always told that applicances are safer when they are earthed, or at least double insulated.

So you didn't need a new volume pot, just a motor connected to the original pot. If you had used the new pot that came with the motor (if that's the easier option), could you easily connect the orignal volume knob? I thought you might have got power from the lighting circuit, espeically if it now uses lower voltage LEDs? Now you mentioned it, I can see on the picture, the IR receiver is where the mute botton was. I didn't notice it at all before, it doesn't look out of place.

All the new RCAs look great too. I'm guessing you had to at least drill new holes in the chassis for the screws to mount them? Did you need to cut away the chassis completely behind those mounting places? Or did everything fit through the holes left where the old RCAs were?

 

[F1nut]

Safer from what? There's all kinds of gear old and new that are chassis grounded, not earth grounded.

Yes, I could have replaced the original pot with the new and made it work, but as previously stated, I wanted to retain the balance control.

I forget the specifics, but there was no suitable tap for power to the new pot.

There was a lot of modification required for the new RCA jacks and a whole host of other stuff. I used black FR4 for mounting panels on the rear. I also used it in various areas inside.

 

[Dr. Ears]

What do you do with some old gear you forgot you had? Restore and upgrade it, of course.

Neither the SA-500 or TX-500 had been used in a very long time and after powering up I could hear they were in need of work. Checking a few caps I found them way out of tolerance, so I replaced all the caps in both using a selection of Elna Silmic and Cerafine. One of the emitter resistors in the SA-500 was cracking, so all 4 were replaced. Some of the semi-conductors needed replacing in both as well. Of course, most of the pots were dirty, so they all got a good cleaning. Things were sounding better now. Intrigued, I decided to make a few upgrades, which I'll just list.

* Replaced the very odd stock binding posts with new 5 ways using black FR4 as a mounting plate.
* Replaced the stock power cords with shielded 16 gauge as there was no room to mount an IEC on either piece.
* Applied Dynamat Extreme to the top and bottom covers.
* Removed the SA-500 speaker On/Off switch from the circuit, making a direct connection from the amp board to the outputs with upgraded wire.
* Upgraded the wire between the pre amp board and the amp board.
* Removed the connections to the switched/unswitched outlets.
* Replaced all the RCA jacks with gold plated copper versions and spaced them further apart to allow the use of modern day interconnects. Again, I used black FR4 as the mounting plates.
* Replaced the SA-500 power light with a diffused blue LED.
* Replaced the TX-500 dial lights with diffused white LED's and the FM Stereo light with a diffused blue LED. Since the tuning meter is an off white plastic, clear blue LED's were used to back light it resulting in a diffused appearance, which matches well with the other blue diffused LED's.

I'm still toying with the idea of replacing the volume control with a motorized version allowing remote control, but since these have ended up in a guest bedroom, we'll see about that.

Thanks to Don (will make just about any LED you want, contact at deh12110@yahoo.com) for his help with the LED's and to Mark for his help with the semi-conductors. Those were two areas I had limited knowledge of, but have learned a lot more about both since I started this project.

I have to say for a little 10wpc integrated amp it sounds a lot better than I ever thought it could, has a kind of tube amp sound....nice! The tuner isn't bad either

Pic 1 - the original RCA's and power cord, I already upgraded the binding posts.
Pic 2 - view of the upgraded RCA's and power cords.
Pic 3 - close up of the new RCA's and mounting board.
Pic 4 - the original lights.
Pic 5 - with the new lights....ah, much better.

I love the sound of my original SA-510, I wish I knew how to upgrade it the way that you did!