Hi guys, It´s been a while since I posted here. I´m investigating the different schems and layouts of the ODS (what a mess!! ) and slowly making my own schem, with the idea of building my own, not really a clone of a particular one, but just one with the features I think will be the most useful for me, and adapting it to the materials I can get. Looking at different schems, I see a functional difference in the master volume: in the #183, the master is always active (in clean and in OD) while in the #101 HRM, when the OD is active, the master is not in the signal path (there it´s called "clean master"). I believe that the second example is functionally better, since the clean and OD masters are truly independent. Or is there something I´m not seeing? The other difference is that one has switches while the other has relays for switching, but that shouldn´t be the reason for the different functionality, right?
The separate master approach is peculiar to ODS HRM's, I believe. Functionally, you'd like to control the relative volume of clean and OD as well as the overall volume. This can be done by controling both independently, or by controling one independently and both together. I don't see much difference, but I'd also be interested in comments from those who have used both systems.
I prefer separate master approach... especially when using D-lator with your amp. D-lator can be used as a master volume for clean and OD at the same time.
mcinku wrote:I prefer separate master approach... especially when using D-lator with your amp. D-lator can be used as a master volume for clean and OD at the same time.
The same is true with the non-HRM set-up- the D'lator's recover out is directly feeding the power amp either way. The separate masters will give you both independently and both together via the D'lator... that's one more knob than you need, though.
OK, I continued to develop my schem, and I´m including a built in Dumblelator, so that gives me another two level-controlling pots... things get more complicated. How do you guys who use the dumblelator manage your levels, with so many knobs? Do you leave the Dumblelator knobs alone and just use the masters?
Mostro wrote:OK, I continued to develop my schem, and I´m including a built in Dumblelator, so that gives me another two level-controlling pots... things get more complicated. How do you guys who use the dumblelator manage your levels, with so many knobs? Do you leave the Dumblelator knobs alone and just use the masters?
I typically set the masters at about 12:00 then adjust the dumblator drive control so that the input of the effect unit (right now it's a quadraverb) is high, but not clipping then adjust the return for overall volume level.
Back to the different functionality. I believe it's more about placing the correct impedance loading on PI input as well as the output of the clean and od stages. Without the HRM treble pot (250k) the 1M master places the incorrect load on the od side. Using a ratio control before the master allows a better match. HAD used 100k to 250k on the ratio. At least that's my understanding.
I've built several of each and haven't found it made much difference in my playing style. I think that is mostly because I don't have a big difference in volume in clean or OD. It's my PAB that gives me the SPL kick. OD just raunches that up a bit. I also have a tendency not to mess with the dials much though so YMMV.
My next build will have a built-in D'lator and the plan right now is to use the circuit with a single MV that is reduced to a voltage divider on the board and using the Return as the overall master. Structo started this thread a couple weeks back on that subject:
If you go with the dual masters, be sure to put enough of a load after V2b. One the schematic I've used there is a 1meg resistor after the coupler going into a 1ma pot with a 180k resistor across it.
I think that if you do want to use the D'lator for a master volume you should use the circuit that has the Send and Return and Output as the Master.
Put the Send and Return on the back panel by the loop jacks and use the fixed divider for the Master volume as talked about in that thread then use the Output pot on the front panel as the Master volume for the amp.
That is basically how I do it with my external D'lator.
I leave the Pre-gain volume and Master volume at about 1:00 and use the Output of the D'lator to control overall volume.
OK. So, make the master a fixed voltage divider and use the loop´s return level as a front panel master. How´s that work at managing gain structure throughout the amp? Does it limit it´s performance at some settings?
Errrrrr, I added a loop on/off switch, so I can´t eliminate the master or I´ll have no final control over level, won´t I? Or the clean vol and OD drive and vol will be enough to control my levels? Or should I leave the loop always online (no on/off switch)?
This is not so easy! But a good learning experience. As soon as I finish the schem I´ll post it so you can see and critique/suggest.
) and slowly making my own schem, with the idea of building my own, not really a clone of a particular one, but just one with the features I think will be the most useful for me, and adapting it to the materials I can get. Looking at different schems, I see a functional difference in the master volume: in the #183, the master is always active (in clean and in OD) while in the #101 HRM, when the OD is active, the master is not in the signal path (there it´s called "clean master"). I believe that the second example is functionally better, since the clean and OD masters are truly independent. Or is there something I´m not seeing? The other difference is that one has switches while the other has relays for switching, but that shouldn´t be the reason for the different functionality, right?
