Hi Jeff - I recently acquired one of these for very cheap and was thrilled to find your videos. I was hopeful you might have some additional details on the components you used here and in your other 1682 video? Cool stuff!
I purchased an used Proteus/1 and it works great midied to my Korg Krome for great Hammond B3 emulation playing Gospel Quartet. Stay Safe and Blessed 🎹🎤🎵🎶🎼🎼🎶🎵🎵🎵🎶🎼✝️🙏🏿😎💯💯💯
Do you still use these? I have a different Biamp board (I bought it from the person who commented on your other video, haha) that features input transformers and is surprisingly quiet! I was thinking of trying to do some simple modifications to open up the hi end a little more and maybe make the EQ more useable. It's a 4-band fixed eq, and I only find the low (80hz) and hi-mid (3k) to be useful on most sources. The Hi (12.5k) EQ works sometimes but seems to introduce mild hiss no matter what mic I'm using. Looks like the power external supply was rebuilt in the past 10ish years. Here is a link to the schematic if you have any interest in looking! No worries if not! Thanks! cdn.biamp.com/software/docs/default-source/downloads/42_series_schematic.pdf?sfvrsn=0
if you have the protologic add-on inside the proteus 1 - then there is no demo-song function anymore. it only works with original and unchanged proteus 1.
you know any background info on biamp? about to go pick up a 24 channel mixing console and cant find anything about the company online other than they were based in portland OR.
They were a low-budget sound equipment company. I don't know their time span but likely started in the '70s and continued through the '80s. Their stuff mostly doesn't sound great but I think the 8802/1282/1682 series may have sounded better than the rest. That line at least had input transformers. Anything that old would at least need the electrolytic capacitors changed since they deteriorate with age. This video is about upgrading the channel strips with higher quality tone capacitors, and doing some extra mods to make them sound more desirable for recording. They are a good candidate for upgrades since they have the basic foundations of a good sounding console, and it is very cheap to buy a used one, and if you are handy with a soldering iron, they're cheap to upgrade as described. I will be putting these channel strips into a rack for my studio, and they will be running on a nicer power supply than the original Biamp mixer they came from. I plan to mod the mic preamp section soon and post a before/after vid for that, although I expect less of an impact than the tone control upgrades.
The bottom counter is just an up-counter driven by a clock. The mess to the right is the reset-detect circuit. When the bottom counter value matches the top counter value, a reset pulse is sent to the bottom counter to reset to zero. The 4 bits on the bottom counter output are intended to drive an R-2R ladder to provide a stepped voltage (staircase wave) for a transistor curve tracer. The top counter is just to set the number of steps in the count cycle. Clicking on the blue reference nodes triggers the top counter to count up or count down. The simulation software does a BCD-to-7-segment conversion internally to the LED displays. To build the circuit in reality would require 7-segment driver ICs.
Can't say I generated a schematic for this when it was built. It was on a breadboard socket and no longer is assembled. However, see my video of the digital counter schematic, which was the start of the plans to build a permanent unit. The up/down toggle would adjust the number of traces. The sweep was via a Wavetek 142, and its sync output would trigger the counter. The counter connected to an R-2R network for D/A conversion to a stepped voltage. The voltage was applied through a 100K or higher resistor to the transistor base, which sufficiently approximates a stepped current source for small-signal transistors. The circuit surrounding the transistor is similar to the simple manually-swept-base-current type circuits on the Web. The Wavetek 142 was set for sawtooth output and drives the scope trace horizontal sweep as well as the sweep voltage to the transistor collector.
Very interesting circuit. There must be more to it, but I can’t find anything other than what’s posted in your RU-vid vids. Can you possibly point to more information? Tks.
I've still got my E-mu Proteus MPS, purchased new back in the mid 90s (staff discount as I worked for Creative Labs who owned E-mu by that time). Over 20 years later and it still works perfectly. Different demo medley than the rack module, but to anyone that's owned a Proteus, unmistakable.
This is a very cool tracer! I just found a very simple circuit that will do a crude version of this too. You can check my channel if you want to see it, it has the circuit and everything.
The traces here are great. I would love to have a schematic of this curve also so I could replicate them. The poster of this video has done a great job.
