I don't know how many you have, but usually the VU meters are used to monitor the outputs (unless you want to monitor the individual channels but that gets pretty pricey, not to mention taking up a lot of room), you can follow the direction given here to build one.
I have infinite room + the gauges are already acquired. I'm using a 4U front-panel that I can build off the back as much as i need. I have 1-VU Gauge + 2-Current Gauges. *I read I need to use a "Shunt" for meters measuring current of higher levels than they can handle. Here is an article I found in making my own (Shouldn't be too-hard as all it is a low-resistance high-current component to hand the meter off of).
*I got my design drawn up.
EF86 Mic Pre (REDD47)
-> LA-2A Compressor
-> Pultec-style EQ
*Choice of EQ Post or Pre the Dynamics
**got my transformers -- but will probably sell the units I got them out of + just buy the Sowter 99XX series made particularly for this build (REDD47).
***I would going use the Output Transformer after the EQ + Dynamics -- I shouldn't have any issue w/ that should I?
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..see that wasn't too hard..
...simple & straight-forward up until here:
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Here are the items that I wish to add that start to make the design confusing:
****I wanted to have the choice of single-ended OR push-pull output. The output is normal Line-Level, not a Voice-Coil. The PP would be done in 1-envelope/tube a ELL80 just need a PI.
*****I like the idea of a balanced gain stage +/or the idea of using an interstate transformer to go from PP-plates to PP-grids. BUT am happy w/ what is mentioned above^ the SE+PP option. For the reason I want the option of both harmonics on the Final-Stage to the Line Output.
...let's leave it at that for now + I'll attach a schematic or at least a box-diagram for u guys to check-out.
Thanks:]
An externally hosted image should be here but it was not working when we last tested it.
So this is a single-channel strip?
So you want them all in-line but with the EQ switchable pre or post the LA-2A? Usually, the compressor is run in the side-chain, i.e., fx-send and return, is that what you have in mind?
An impedance matching transformer might be needed, but it depends what comes after the channel strip, what is it driving? A tape machine, a soundcard, or power amp?
Jazbo:
Yes. Single Channel -- Mono
Yes. In line w/ EQ Pre or Post.
Yes. On ability to have a Sidechain-input for the compressor. *(people have different definitions of sidechaining. My understanding of the world is to have an input that Fires the Compressor such as an external track's Kick-Drum). I would love to hear your take on SC because I know it has different application/definition to different people.
It will be driving a Computer Soundcard/ Interface such as the PRE SONUS FP10 FIREBOX *(1-Meg load, line-level at either -10dbu or +4dbu-fs -- a soundcard).
Yes. Single Channel -- Mono
Yes. In line w/ EQ Pre or Post.
Yes. On ability to have a Sidechain-input for the compressor. *(people have different definitions of sidechaining. My understanding of the world is to have an input that Fires the Compressor such as an external track's Kick-Drum). I would love to hear your take on SC because I know it has different application/definition to different people.
It will be driving a Computer Soundcard/ Interface such as the PRE SONUS FP10 FIREBOX *(1-Meg load, line-level at either -10dbu or +4dbu-fs -- a soundcard).
Jazbo are my values for impedance correct? I square the turns ratio & that is my Impedance at the tested frequency I used? (ie.@1khz).
Or an I missing something -- seems almost too easy.
Some of the #'s I got, for example the UTC HA-100X input transformer I got Z=100ohms @1khz.
Or an I missing something -- seems almost too easy.
Some of the #'s I got, for example the UTC HA-100X input transformer I got Z=100ohms @1khz.
Here are my Impedance #'s for the Altec TMB-156 transfo:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
That's the impedance ratio, not the actual impedance. If the transformer has a turns ratio of 10:1, then it's impedance ratio is 100:1, so whatever impedance you put across the secondary will appear 100 times larger when looking into the primary. So if you attach 10 ohms to the secondary it will appear as 1000 ohms at the primary (although the reactance of the primary inductance sets the upper limit on how high it can go).
OHH, Impedance RATIO. Got-it😉 Thank-you so much Merlin:") glad to see u here helping out -- hope I didn't bother u too much w/ all those ADHD e-mails 😛
This wouldn't be of any use at the Output would it? Since we (me) are trying to retain all the Sonics/transients/harmonics & use Gain Reduction + Dynamics to control the volume -- a clipper is irrelevant correct?
An externally hosted image should be here but it was not working when we last tested it.
Found this -- it's a breakdown of the different stages of the LA-2A. Very helpful for me to understand the circuit to be able to incorporate it😉
I'd like to attach the schematics for the DISA + Collins Tube Limiters, but then I'd end up attaching the Fairchild + every single dynamic unit in between lol
Question: I only need 1-input + 1-output transformer for my entire channel strip correct -- at the front-end + balanced output -- correct? So my 3-seperate designs/modules (Pre, Comp, Eq) can be linked together at their high-Impedance inputs+outputs -- ie. Remove the input + output transformers. Right? This is because they all are high-immpedancd designs w/ balanced low-Impedance transformation-stages (transformers) at their beginnings + ends... Right?
Yes, if you plan to have them all in one strip then you do not need the the transformers in between. My comment on the side chain does not seem to apply in your case, since it's "all-in-one".
Jazbo, I decided to add a SC input. But regardless, Jaz help me understand this:
So on the LA-2A breakdown diagram I attached ^above^ one of the Gain Stages is labeled: "SIDECHAIN AMPLIFIER" + thee other "MAKE-UP GAIN CIRCUIT". I know the word sidechain is being used in the same context here -- but I do not understand the design or purpose in this specific application. I know sidechain means to control/trigger one thing w/ another... But in this instance I do not understand it as there is no external gear or signal -- unless it's calling it Sudechainng because one component of the system is controling another component of the system... And I'm just looking into it too-deeply (too-much) as I do w/ everything in my life (specially my hobbies, loves + fears). But since I don't believe this is a board nor a thread on Life-Coaching.. I won't mix thee two😉
But Ya, sidechaining to me is triggering a signal via another such as compressing a synth via kick-drum. In this instance I imagine 2-different signals running parallel that are then mixed together? As in "New York" compresion when u split 1 signal into 2 running parellel + compress + the other dry -- then mixing the 2 signals together.
But ya, the Diagram says Sidechain Amplifier -- so I'm guessing its internal. 1-component controlling/triggering another.
So on the LA-2A breakdown diagram I attached ^above^ one of the Gain Stages is labeled: "SIDECHAIN AMPLIFIER" + thee other "MAKE-UP GAIN CIRCUIT". I know the word sidechain is being used in the same context here -- but I do not understand the design or purpose in this specific application. I know sidechain means to control/trigger one thing w/ another... But in this instance I do not understand it as there is no external gear or signal -- unless it's calling it Sudechainng because one component of the system is controling another component of the system... And I'm just looking into it too-deeply (too-much) as I do w/ everything in my life (specially my hobbies, loves + fears). But since I don't believe this is a board nor a thread on Life-Coaching.. I won't mix thee two😉
But Ya, sidechaining to me is triggering a signal via another such as compressing a synth via kick-drum. In this instance I imagine 2-different signals running parallel that are then mixed together? As in "New York" compresion when u split 1 signal into 2 running parellel + compress + the other dry -- then mixing the 2 signals together.
But ya, the Diagram says Sidechain Amplifier -- so I'm guessing its internal. 1-component controlling/triggering another.
Found this -- it's a breakdown of the different stages of the LA-2A. Very helpful for me to understand the circuit to be able to incorporate it😉
I'd like to attach the schematics for the DISA + Collins Tube Limiters, but then I'd end up attaching the Fairchild + every single dynamic unit in between lol
For me a "side chain" is just a fany name for effect send/return in the channel strip, but inside the LA2A schematic posted above, it has a different meaning, but why not just called it an "Attenuator Drive Amplifier" which is the term that Tektronix used to describe its function. Calling it a "side-chain amplifier" simply muddy things up even more...🙄
I started out making things out of salvaged parts back in the 60's because that was all that was available to a kid that wanted to play with electricity. Fortunately the local trash dump was full of TV's, radios and HiFi sets with plenty of tubes, transformers, and other good parts. Back then these parts were only a few years old, and INTENDED for consumer grade audio applications.
I had amassed a large collection of stuff, and managed to fix up a good shortwave radio and TV for myself, but I wanted to build SOMETHING! Armed with a cursory knowledge of electronics, a huge collection of parts, and dozens of schematics from the magazines of the day, I tried to build simple guitar and stereo amps with limited success. I could build what I thought were two identical amps, one would "work" and the other would sound terrible or just smoke. Hey the parts were free, and I was a curious kid, so I just made another......
A local ham radio guy gave me some excellent advice. Make ONE good project, get it working really good, then use it as a "benchmark" to test your ideas and parts out. He helped me make a good working guitar amp with two or three tubes (I don't remember now). It was point to point style on a piece of pine with the layout drawn in ink so that I could always put it back together. I kept the "golden parts" separated for use only in this amp so I could always get it back to the original state.
This turned out to be excellent advice. I now had a working guitar amp that I could test my parts. One by one I went through my collection of "output transformers" and found some that worked better than others, and some that didn't work at all......I didn't quite understand that "impedance matching" thing yet. I also learned that for reasons that I didn't yet understand (load lines and impedance again) the big fat tubes (6DQ6) didn't work as well as the skinny ones (6BQ6).....which one do you think a kid wanting to make a guitar amp used????? Within a year I was making cigar box guitar amps for my friends.
My advice would be, to figure our which channel strip (or whatever) you want, get the schematic, and buy the necessary parts to copy it EXACTLY as designed. Make it work, document it, then start swapping in your parts, ONE AT A TIME, to figure out what works and what doesn't in your project.
The choke shown in the bottom of the last picture in post #7 came out of an old HP audio oscillator. The power transformer from the oscillator is good for a 35 watt guitar amp. Depending on model, it came with 6CW5's or 6K6's, 6AU6's and possibly an Amperex Bugle Boy 5AR4 (newer ones had SS diodes). All of this is useful stuff, as is the stainless steel hardware, and as you show, the knobs.
I had amassed a large collection of stuff, and managed to fix up a good shortwave radio and TV for myself, but I wanted to build SOMETHING! Armed with a cursory knowledge of electronics, a huge collection of parts, and dozens of schematics from the magazines of the day, I tried to build simple guitar and stereo amps with limited success. I could build what I thought were two identical amps, one would "work" and the other would sound terrible or just smoke. Hey the parts were free, and I was a curious kid, so I just made another......
A local ham radio guy gave me some excellent advice. Make ONE good project, get it working really good, then use it as a "benchmark" to test your ideas and parts out. He helped me make a good working guitar amp with two or three tubes (I don't remember now). It was point to point style on a piece of pine with the layout drawn in ink so that I could always put it back together. I kept the "golden parts" separated for use only in this amp so I could always get it back to the original state.
This turned out to be excellent advice. I now had a working guitar amp that I could test my parts. One by one I went through my collection of "output transformers" and found some that worked better than others, and some that didn't work at all......I didn't quite understand that "impedance matching" thing yet. I also learned that for reasons that I didn't yet understand (load lines and impedance again) the big fat tubes (6DQ6) didn't work as well as the skinny ones (6BQ6).....which one do you think a kid wanting to make a guitar amp used????? Within a year I was making cigar box guitar amps for my friends.
My advice would be, to figure our which channel strip (or whatever) you want, get the schematic, and buy the necessary parts to copy it EXACTLY as designed. Make it work, document it, then start swapping in your parts, ONE AT A TIME, to figure out what works and what doesn't in your project.
The choke shown in the bottom of the last picture in post #7 came out of an old HP audio oscillator. The power transformer from the oscillator is good for a 35 watt guitar amp. Depending on model, it came with 6CW5's or 6K6's, 6AU6's and possibly an Amperex Bugle Boy 5AR4 (newer ones had SS diodes). All of this is useful stuff, as is the stainless steel hardware, and as you show, the knobs.
Great input -- i have about 90% of what you said implemented in-mind.
i have picked a Mic Pre = ef86 REDD47
picked an Compressor = LA-2A
picked an eq/s = Pultec EPQ-1A + MEQ-5
the eq's + compressor will be switchable & option to be Pre or Post
I have all parts for the Mic Pre, LA-2A + Pultec EQ's
EXCEPT: Opto Cell.
ill start drawing out a Box-Diagram of the single-flow & the added do-da's i wish to implement/add.
Thanks guys! & tubular.com :")
—±2∏Øthee.
Signalchain😀one
*forgot to add:
the serrate modules will be interconnected via their high-z connections (no transformers other than interstage/s) Input & Output Transfo will be a the front-end & rear
**lastly their will be 2-seperate (if not 3) final gain stages:
SSRP
Push-Pull
Discrete
***after build I'm going to add the Pete Millet Mic Pre + Neve N72 clone
once they are all all assembled I'm gonna find my fav combo, keep that, then re-build all the other universe into individual units just to have for back-up
now I can have these ALL as individual units -- however that is A LOT more iron than i have available atm,
peace.
*forgot to add:
the serrate modules will be interconnected via their high-z connections (no transformers other than interstage/s) Input & Output Transfo will be a the front-end & rear
**lastly their will be 2-seperate (if not 3) final gain stages:
SSRP
Push-Pull
Discrete
***after build I'm going to add the Pete Millet Mic Pre + Neve N72 clone
once they are all all assembled I'm gonna find my fav combo, keep that, then re-build all the other universe into individual units just to have for back-up
now I can have these ALL as individual units -- however that is A LOT more iron than i have available atm,
peace.
You can get Vactrols from Mouser I believe, about $5 each......I got these to experiment with. They vary a bit more from part to part than Vactrols, but they work......
Electronic Goldmine - Audio Opto Coupler
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