Hey Woods aficionados, does anyone know if Walter added the phase switch later to the MI 100-8 or did he drop it toward the end? I'm checking one out that has no phase switch or stereo/mono switch?
Enjoy the benefits of a premium membership!
Upgrade Account
-
TalkBass has been independent since 1998. Add your voice.
Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
Join free Log in
Want zero display ads or expanded classifieds tools? Compare plans.
Double Bass Early Walter Woods MI Amps? No Phase or Stereo Switch?
- Thread starter dylanjohnson
- Start date
Dylan,
I’ve never seen one but, that doesn’t mean that it’s anything unusual, there are so many varations on Walter's amps that it's impossible to keep track. When I purchased one of the early two channel version of the MI-100-8 in 1979,
that year's line had a single channel with a boost switch (that never appeared on any other amp) a four channel that he built for the Syndrum, a two channel, and a 225 watt single and dual channel and a version with
the 8 pin power jack for an Alembic bass. Those DPDT switches were part of the signature sound of a MI-100-8 because they boosted or cut the bass or treble response. Very effective and simpe equilization.
My WW ElectrAcoustic amp does not have a phase switch, so before I acquired the FDeck HPF, I made a speaker cable that was wired Phase Reversed. (I make all of my own speaker cabs and cables, and always use a Double Banana Plug for the connection.)
It was a quick and easy way to reverse the phase of my signal chain.
There is an online interview with bassist/engineer Steve Rodby that opened up my tiny brain (and ears) to the importance of "phase" in the DB amplification process.
Thanks.
It was a quick and easy way to reverse the phase of my signal chain.
There is an online interview with bassist/engineer Steve Rodby that opened up my tiny brain (and ears) to the importance of "phase" in the DB amplification process.
Thanks.
@Don Kasper, I'd love to hear that if you remember the video. I'm speaking specifically of these early MI series amps. It looks like the early ones did not have the switches, but who knows with Walter! Great idea for switching phase!
I think this link will take you toward the interview/podcast.
Thanks.
Link Removed
I’m not entirely sure that’s the case, I had two different MI series amps. My first was a MI-100-8 built in 1980. At that time according to Walter’s sales brochure he offered four different amps the MI-100-8, MI 225-8, a power amp and the single channel MI-100-8. All of those amps had phase and “stereo/mono switches” That switch requires a separate amp to run in stereo. There was also a boost switch on the single channel that apparently ganged the two preamps in the chain. I bought a two channel MI-400-8 in 1992 it had the same switches. Post 1993 Walter started changing the preamps. The amp someone here on TB dubbed the “Slider” because it had variable bandwidth controls that worked with each of the tone controls. At that point the switches started to disappear.
This is a hare to see picture from an old thread we did of a stereo version of the slider. The top controls are marked B vari, M vari, and T vari.
This is a hare to see picture from an old thread we did of a stereo version of the slider. The top controls are marked B vari, M vari, and T vari.
Last edited:
This is the amp that posed the question. It isn't a slider, but might be one of the later era ones before Walter changed the design.
Interesting, now that I see this amp I seem to remember that he did just eliminate the Phase Switch on the MI-100-8's, but for some reason he put it back on my MI-400-8 that was built in
1992 Here's a picture of that amp. The manufacturing date is stamped into the cooling fins. on the top side of the amp.
1992 Here's a picture of that amp. The manufacturing date is stamped into the cooling fins. on the top side of the amp.
I think you meant the Sweeper.
Also the Sweeper was part of the MI-200-8 line that also included a 2 channel preamp model of which I owned 2 of. I still have the brochure, I'll scan and post later. It was around '95 that he phased these out and went to the Electracoustic which also included a 2200 watt model that I also owned, at least briefly til he recalled it due a design flaw that would cause it to catch fire. He only made 5 of those.
Last edited:
Actually I think it's more like a late 70's going by the switches and the black panel screws, well before he built the MI-200-8 models that included the Sweeper.
FYI/TMI - my earlier post regarding "phase" was in reference to the speaker "phase" issue, i.e., addressing if the speaker cone first moves OUT or IN. Was Walter's Phase Switch used for STEREO capabilities and applications on his products?
These are 2 different issues, as I understand them.
My (simple) understanding of "phase" is that the bass/pickup and the speaker can be In or Out of phase with one another - one setting usually sounds better than the other. IME.
2 Stereo channels can be In or Out of Phase with one another, I think. (I have no experience in this realm.)
Note: IANAEE - I am not an Electrical Engineer.
TY.
These are 2 different issues, as I understand them.
My (simple) understanding of "phase" is that the bass/pickup and the speaker can be In or Out of phase with one another - one setting usually sounds better than the other. IME.
2 Stereo channels can be In or Out of Phase with one another, I think. (I have no experience in this realm.)
Note: IANAEE - I am not an Electrical Engineer.
TY.
Couple more. One of these tells which models had the phase or stereo switch.
Yeah, the switches are like the ones on the original Min Amp. Thanks for the brochures! I've never seen those ones.
It would be neat to make a thread of documentation from Walter for reference. I've seen lots of brochures and manuals for different amps over the years in different threads here on TB.
I was thinking the same thing. We actually did that, it's called Walter Woods History and development, but we didn't get very far and when I checked it recently all the pictures we posted were deleted, I assume because as threads get older the photos
take up a lot of server space, so they remove them somehow. If we really want to do it right we need to create a Talkbass Wiki like they did for Ampeg, but that's a big undertaking.
I'd be willing to host a google drive folder that everyone could access. I've already started it.
I just went through several pages of that thread and could find no deleted photos.
Walter Woods Amps History and Development
That is the exact amp I have. And it is called "Sweeper", according to WW's handwritten headline on the users manual (one yellow A4 paper printed on both sides).
I have an addendum sheet for my 2-Channel MI 400-8. Regarding the PHASE switch it says "The Switch marked "PHASE" is for use with two pickups or stereo instruments. It has the same effect as the phase switch on a guitar and is electrically the same as reversing the wires from one of the pickups. For single pickups, the "in" position is preferred"
