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Walter Woods Amps History and Development

#821
I don't have any experience with WW's two channel amps with a Mix switch (the Super I had did not have that feature on it). Let us know how that goes, thanks.

Do those cascade the two preamps, or is it like a channel select switch that would run the two channels in parallel when set to Mix?
 
#823
Hopefully this will help someone keep these legendary old amps going. Also you can see how the mix switch works on the MI100.

After Christmas I’ll post pics of my old 79’ green light WW I refurbished with a bridged hypex amp/psu @1000w.

I sold my blue light ultra many moons ago to fund an overseas holiday when they were going for crazy $.
 

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#824
barneybass said:
Hopefully this will help someone keep these legendary old amps going. Also you can see how the mix switch works on the MI100.

After Christmas I’ll post pics of my old 79’ green light WW I refurbished with a bridged hypex amp/psu @1000w.

I sold my blue light ultra many moons ago to fund an overseas holiday when they were going for crazy $.
Click to expand...
Is that schematic from an actual unit? It doesn't match what I have, starting with the gain blocks.
 
#828
i have one of these amps with the mix switch. its only got one channel for the eq, so its really a one channel amp i guess. 2 imputs though. when you use input one, and mix switch is not engaged, the gain stages appear to be in parallel, with mix engaged, the seem to be feeding into each other and you can get very rich harmonics, to downright distortion. also, on this amp, the mid control acts like a volume. mid all the way down = no sound. i know that's normal for a fender tone stack, but i didnt think this amp was based around that...
 
#829
barneybass said:
Hopefully this will help someone keep these legendary old amps going. Also you can see how the mix switch works on the MI100.

After Christmas I’ll post pics of my old 79’ green light WW I refurbished with a bridged hypex amp/psu @1000w.

I sold my blue light ultra many moons ago to fund an overseas holiday when they were going for crazy $.
Click to expand...

That's a great idea! Keep the classic tone of the pre-amp and simple swap the power amp. Hypex are some of the best class-d amp modules around. Are you using the SMPS for the Hypex also for the pre-amp?
 
#830
barneybass said:
Hopefully this will help someone keep these legendary old amps going. Also you can see how the mix switch works on the MI100.

After Christmas I’ll post pics of my old 79’ green light WW I refurbished with a bridged hypex amp/psu @1000w.

I sold my blue light ultra many moons ago to fund an overseas holiday when they were going for crazy $.
Click to expand...

Great,
I still have my Electroacoustic Ultra, although I rarely use it. Could the same "upgrade" be possible for the Electroacoustic's. Mines fine at present, just thinking
about the future. Aftermarket sales of Walters amps have cooled off quite a bit.
 
#831
Jeff Scott said:
I don't have any experience with WW's two channel amps with a Mix switch (the Super I had did not have that feature on it). Let us know how that goes, thanks.

Do those cascade the two preamps, or is it like a channel select switch that would run the two channels in parallel when set to Mix?
Click to expand...

I think it's a channel select switch. I fooled around with it yesterday and I didn't hear either a change in tone or gain! I used to run it in "mix" when I had 2 basses plugged in (one was a fretless). Interesting that I have the original 2 page manual and there is no mention of the mix switch or its uses. I also have the original schematic tucked inside the amp. If you have a bass plugged in to channel 1 and have the switch set to channel 2, you get no sound.
 
#834
Ric Vice said:
Great,
I still have my Electroacoustic Ultra, although I rarely use it. Could the same "upgrade" be possible for the Electroacoustic's. Mines fine at present, just thinking
about the future. Aftermarket sales of Walters amps have cooled off quite a bit.
Click to expand...
What "upgrade"? Why?
 
#836
Ric Vice said:
Great,
I still have my Electroacoustic Ultra, although I rarely use it. Could the same "upgrade" be possible for the Electroacoustic's. Mines fine at present, just thinking
about the future. Aftermarket sales of Walters amps have cooled off quite a bit.
Click to expand...
What "upgrade"? Why?
 
#837
byacey said:
I can't think of any other good reason why he wouldn't include a value for those particular resistors, if all the others are marked on the schematic. Perhaps he selectively biased it to add a little bit of distortion.
Click to expand...
The value is provided, it’s different than what was posted. There’s no notes about trimming this value and because there is adequate headroom there’s really no reason to bother.
 
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#839
Re the mix switch, there are probably variations out there. If you have an early amp they needs repair your tech will be able to verify if the above schematic is the same as yours or not.

I used the hypex NC502 which has an auxiliary psu which powers the WW preamp and a small interface pcb.

Interface pcb designed by the tech who generously released his work above to help others.
 
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#840
I would love to attach a mi-100 preamp to a hyphex power amp. I’m always looking for another mi-400 so I have a backup of my current rig, but i don’t think I will see another one of these anytime soon. Did you do this work yourself? Do you know of anyone who could do custom work like this on a mi-100 @barneybass ?
 

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