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Help Motorola hs 696c tube amp

R

robsrockin

Member
Hi all,Greetings from Jacksonville,Fl.I am very new to this site and to tube amps.I hope I'm doing this correctly.I have this motorola hs-696c amp that I can't power up.I did read a previous thread about needing to jumper the pre-amp interconnect to add a power switch.This is not something that I know how to do so my question is,can someone tell me how to do this or maybe have a print on how it's done that can be posted?I also need to know if this amp should turn on when plugged in or if it needs to be told to turn on.Any assistance would be appreciated.I do know enough about tube amps to know that if I do this wrong I could set my hair on fire and I really would like to keep what little i have left on my head.Thanks for any help I get.robsrockin1@yahoo.com
 
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Are you using the preamp with this or just the basic HS-696C amp? There is an 8-pin socket on the HS-696C that is used to connect to the preamp and the power is switched from there. I've attached a part of the PS schematic that someone once posted here. Assuming you're not using the preamp then 120VAC power comes in to the amp with the black/hot connected to pin 5 and the white/return to pin 3. The Power transformer input winding should be connected to pin 1 and pin 3. If that is the case in your amp, then you would need to jumper across pin 1 to pin 5 to power the amp. I would suggest adding an On/Off switch into this (mounted on the side or top of the chassis) and also add a fuse (again a fuse-holder to the side of the chassis or you can use an inline fuse underneath).
 

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Thank you for your quick reply to my post.I am just using the amp and that print you sent me will be very helpful.You know it seems like I recall seeing your name from the previous post that I was reading about this amp,I think the guy that had that amp calls himself Fast Eddie, the amp was painted red and was very nice on the eyes.Thanks again Bud,Robert.
 
Tinkerbelle said:
Are you using the preamp with this or just the basic HS-696C amp? There is an 8-pin socket on the HS-696C that is used to connect to the preamp and the power is switched from there. I've attached a part of the PS schematic that someone once posted here. Assuming you're not using the preamp then 120VAC power comes in to the amp with the black/hot connected to pin 5 and the white/return to pin 3. The Power transformer input winding should be connected to pin 1 and pin 3. If that is the case in your amp, then you would need to jumper across pin 1 to pin 5 to power the amp. I would suggest adding an On/Off switch into this (mounted on the side or top of the chassis) and also add a fuse (again a fuse-holder to the side of the chassis or you can use an inline fuse underneath).
Click to expand...

Damn girl, you never cease to amaze me with your knowledge base.:thmbsp:
 
Is this thread still alive? I'm looking at one of these amps with the preamp. Have yours turned out to be nice sounding units?
Thanks,
 
The Motorola is a good little unit; EL84/6BQ5 tubes are very nice sounding tubes IMO.
 
I have a Motorola amp sounds great.....they fly under the radar and are not as expensive as the Magnavox console pulls. However I have never heard a Maggie tube amp so maybe those sound better. I have said it many times but if you have a three channel setup with the bass on a single 6BQ5 tube use a Bose accoustimass passive sub for the bottem end sounds great.
 
I was gifted one of these amps and would like to do the same thing..use it without the preamp. In addition to jumping the power supply, don't the signal pins in that socket also need to be jumped? And if so, can anyone elaborate on the specifics? Thanks!
 
monkeeboy20 said:
I was gifted one of these amps and would like to do the same thing..use it without the preamp. In addition to jumping the power supply, don't the signal pins in that socket also need to be jumped? And if so, can anyone elaborate on the specifics? Thanks!
Click to expand...
There are two incoming RCAs on board for audio signals from the preamp. It is assumed that your separate preamp will have its own power and indicator.
 
bacinani said:
What are some quick upgrades to these Motorola Console amps. Are the OPT worth replacing?
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They perform pretty good as-is. I did modify one with some PACO SA-40 iron because the original OPTs were non-operational and that turned out great but lots of choices there. You can easily add new speaker terminals, power switch/indication, fuse, etc. as well as relocate everything including the input RCAs for interface cable convenience and add a good looking wood base or case if you want.
 
Ok, I'm back again with more questions.

I want to remove the 8 pin plug from this unit ( and use a seperate preamp)
I have all but 1 set of the secondary leads accounted for, so to speak. The final set, the green ones, go to the plug and then have 2 wires each that go to the 12ax7's. In looking at the schematic, one wire goes to the filaments and the other goes to the filament center tap. So my question is this:

Do both filament leads go on the same green secondary lead and then the 2 center tap leads go on the other. OR do they stay the way they are now, with 1 filament and 1 center tap per secondary lead? Here's a photo



Thanks!

John
 

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monkeeboy20 said:
Do both filament leads go on the same green secondary lead and then the 2 center tap leads go on the other. OR do they stay the way they are now, with 1 filament and 1 center tap per secondary lead? Here's a photo
Click to expand...

A 12AX7 has a 12.6V heater with a 6.3V center tap. In order to use the 6.3V heater connection, the both ends of the 12.6V heaters are tied together and 6.3V is impressed between the tied ends and the center tap.

You can view how the things are connected in the following thread.

Good luck.
 
I stumbled on this old thread after working on one I've had sitting on a shelf for a long time.....Brought it up slow and all looked good.....then went ahead and added a three pronged power cord, fuse and a switch (and jumper). Man, this little thing is old, ugly but sure can sing! A bit of a sleeper in my opinion.
 

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Cool and yes they do sing nicely. I have 1 rebuilt and it looks old and nasty. I used a house ground to the frame and ground green wire to plug with a lifted ground for the amp. I also used USSR era paper in oil caps and orange drop caps in mine along with bigger electrolytics in the amp. I rebuilt and use the RR tape preamp which has some great clean gain.to it. I am sure others will chime in and yes, it is vary much worth the effort to rebuild if inclined. I have another on the shelf waiting to be rebuilt. I am going to mount it in an old wood GE phono radio box. It came with the Stereophonic and Motorola Emblems and they will look really cool on that wood box with the preamp mounted where the radio glass was above them. It will be a gift to my son in law when he graduates from law school along with some Altec 9849 speakers. Mini 19's. I have a year and a bit to get it done.
 
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