First off, thanks for all the comments on this board -- you guys have all helped me tremendously through the years for all kinds of issues!Short version:
I need a stereo Y-cable for speaker-level loads, anybody know of a cable manufacturer that makes those? Cabinet has a single, TRS 3-conductor input jack. I’ve looked but haven’t found any matches for a rather odd question. Apologies if this is answered somewhere and I just missed it but I’m hoping to get some help from you signal wiring guru’s. I’ve scoured the internet but have yet to find anything similar. Long version follows.
I’m using a Triaxis/2:90
into a 16-ohm Marshall 1960 Classic 4x12 cabinet
with 16-ohm 25-watt greenbacks. That cab has been re-wired as an 8-ohm stereo cabinet
so it works fine with the 2:90 or my Mesa 20/20. Since the cab has only a single input jack, I’m currently using 2 speaker cables from the 2:90’s left and right channels and running that into a simply Y-cable, basically an insert cable per the engineer that re-wired the cab. The Y-cable has 2 female mono TS inputs to a single TRS male output.
I’ve been a little worried about some sounds I’ve been hearing from my amps so I started doing some research into speaker-level wiring vs. instrument-level cables. I asked some cable manufacturers about getting me a speaker-level
Y-cable but they’re not familiar with anything like this. The connections have been this way for 15+ years without any obvious issues but I decided to look for a REAL speaker-level Y-cable. The cable manufacturers I spoke to were really helpful but had no idea how this type of setup was configured, nor did they have any type of what they termed "3-conductor" speaker wire. Makes sense, but is this all that unique? Maybe so...
I started questioning whether or not I was saying something wrong and I couldn’t remember how the engineer had re-wired the cab. So I finally opened it up to figure out the mystery -- it's using a single stereo input jack so I borrowed some ideas from a few sites to create my own drawing of the jack and the wiring to help explain things (mostly for my own sanity).
As for the original wiring, fortunately I'd kept a drawing from 1998, no idea how I found that but I pulled out an old box with connectors and diagrams and I'd saved a sketch of the BEFORE setup. Again, the cabinet is a standard Marshall 4x12 16-ohm cabinet that was previously wired up as in this first image (16-Ohm Mono), that is, if my drawing is correct. I think that's called Series / Parallel
but again I'm not a wiring expert. If image is missing the URL should work:https://app.box.com/s/kmk6vvcps86dhg5ga4w52ik4p8qzryvg
The stereo amp I use had no 16-ohm out so by re-wiring the cabinet the way he did, the engineer was able to achieve an 8-ohm stereo cabinet. I remember us talking about re-wiring but we didn't want to cut the wood and change the single input jack to a wider "dual input" so I guess he used a single TRS jack in a creative way -- I think it's basically configured internally like a Y-cable as well where the TRS jack has split the signals -- there's a small image of what I believe was done in the top right of the first image below. He used the TIP and RING connectors to drive the positive speaker posts and wired the SLEEVE connector to all the negative posts on each of the 4 speakers like in this image. Again, if image is missing the URL should work:https://app.box.com/s/zijywhevpm8t8kcs2ep7dzce0w0mdfp9
After the change, I run two normal speaker cables (nice, big 12 gauge), one from the Right and one from the Left 8-ohm 2:90 outputs (picture on bottom right) into a simple insert Y-cable to transforms the two TS male 1/4" speaker cable inputs to a single TRS 1/4" male output used to plug into the speaker cabinet's single TRS input jack. It's absolutely is working as a stereo rig -- I have clear left channel and right channel separation through the top and bottom left and top and bottom right. It's nice and loud and there seems to be no obvious signal dropoff.
But it's that "simple insert cable
" that causes me concern. I'm worried about running it like that using the "insert" Y-cable rather than real speaker cables built for large amp loads. Given that it seems to work today, do you all have any concerns other than my own that this setup work be OK long term?
BTW, I also have a Mesa 2x12 that I've used with both the 2:90 and the 20/20 but I'd like to use this Marshall 4x12 as well. Any other options without trying to re-wire again? Other thoughts or concerns on how this thing is wired up?