I am working on a few projects concurrently and this is 100% true. Unfortunately, i am having to split buys from mouser, digikey, parts express, and other component OEMs directly. Racking up the shipping charges along the way.
I have used a 15V dual supply transformer. After rectification and under load it falls to +-12V. Works great as well.😉
My Whammy has the 22V transformer with the LED reference and the opamp is seeing about 16V under load.
If I wanted to bring that down to 15V (or just under), is the recommendation to short R9 and R13? Or is there a preference to work out the math for the voltage divider via R9,R10 & R13,R14 (if that's even possible to hit with my transformer)?
If I did the "naked reg" config, I need to remove D5 & D6, but retain C8 & C10, correct?
If I wanted to bring that down to 15V (or just under), is the recommendation to short R9 and R13? Or is there a preference to work out the math for the voltage divider via R9,R10 & R13,R14 (if that's even possible to hit with my transformer)?
If I did the "naked reg" config, I need to remove D5 & D6, but retain C8 & C10, correct?
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another option to increase the resistance of CRCRC resistors ... Led + capacitor reduces the noise level in the regulator.
15V AC after rectification should be 15 x 1.41 = 21.15 VDC, was that a typo - did you mean 21V?
Naked reg you leave the diodes in and just wire link for R9/R13 to connect gnd pin to gnd. Nothing else, do this if you want to use LDOVR or Sparkos regs etc.
Well, I only have these Dale 10ohm 1/4W resistors lying around. While I've heard these Vishay Dale resistors tend to be under spec'd, it's probably not smart to try with 1/4W in the CRCRC positions. 
If I'm going to place a parts order, I should probably try and calculate this out, huh.
If I'm going to place a parts order, I should probably try and calculate this out, huh.
Dropping more voltage in the raw supply is not the answer - the regulators are going to attempt to regulate to their set voltage of 15V+Vfwd of the LED. Even if you drop 2-3 volts there, it’s still more than 16.5, and the regs will regulate.
“Naked regulators” is the answer. Remove parts and add jumper until it looks like this -
“Naked regulators” is the answer. Remove parts and add jumper until it looks like this -
Thanks, 6L6. I'll give the naked regs a shot, and if the [inaudible] noise bothers me, I'll look into discrete regs to compensate. $$$
Working backwards from the LED build, it seems I'd only have to remove the LEDs, and add the jumpers, right? Or do I need to remove the capacitors as well (looking at your picture)?
Working backwards from the LED build, it seems I'd only have to remove the LEDs, and add the jumpers, right? Or do I need to remove the capacitors as well (looking at your picture)?
6L6 is absolutely right, I forgot that then the regulator must be changed to a lower voltage ... and then it probably doesn't matter if the heat remains on the resistors or on the regulator
Opa1611 is the single channel version of opa1612, so you'll need 2 of them on an adapter. Plenty of people report that they really like opa1612, so it should work ok
If your OP amp is pulling a little bit of current (like the burson V6), you could increase R35/R36 to increase the voltage drop to the OP amp.
I am actually testing with the Burson V6. I'm also testing dual AD825 on a Brown Dog adapter (sounds great so far on naked regs -- seems a tad more organic/warmer). I wonder if increasing R35/R36 with the LED config is preferential compared to naked regs (without a discrete reg)..?
One of the things that people don’t understand is that in the real world, regulators are really inexpensive solutions, and big caps, filter resistors, and oversized transformers are breathtakingly expensive... The real job on noise is being done by the CRCRC, which is comparatively so expensive that you never see it outside of specialist audio. The regs are there merely for voltage stability.
At least with the burson it would be. Yoy get significant voltagedrop with that current draw. The AD OP amp do not draw the same amount of current, so voltagedrop will be a lot less. But it also handles higher voltage if my memmory serves me right. +/-18V?
Another reason why I love this site... always learn something new. 🙂
I'm going to run naked regulators (which is currently just below 15V under load), and get along with that for the V6's.
On the builds for my brothers, I'm going to just go LED config and run OPA2134 (which can handle +/-18V). I don't suspect they'll ever really dive into rolling botique opamps 😛
Thanks again all for the help.
Hello all,
I thought that I had everything pretty well figured out, but some recent posts have raised a few questions that I would like clarified. I have been gathering my parts for about nine weeks now. I will be using an 18V transformer with Sparkos regulators. I am also planning to use a Burson V6 discreet OP amp.
What is the preferred regulator configuration for my specific build? I thought that the LED reference would be best, but maybe I should go “naked.” Some members have mentioned increasing R35 & R36 to increase the voltage drop at the OP amp. Is this advisable? If so, what is the recommended value for R35/R36? And finally, what about gain and bias? Should I stick with the “stock” values?
Thanks to everyone that can share their knowledge/opinions!
I thought that I had everything pretty well figured out, but some recent posts have raised a few questions that I would like clarified. I have been gathering my parts for about nine weeks now. I will be using an 18V transformer with Sparkos regulators. I am also planning to use a Burson V6 discreet OP amp.
What is the preferred regulator configuration for my specific build? I thought that the LED reference would be best, but maybe I should go “naked.” Some members have mentioned increasing R35 & R36 to increase the voltage drop at the OP amp. Is this advisable? If so, what is the recommended value for R35/R36? And finally, what about gain and bias? Should I stick with the “stock” values?
Thanks to everyone that can share their knowledge/opinions!
Serendipitous timing lol. You can learn from my same questions above. 🙂
If you're going to use discrete regulators and opamps, you'll probably be best going with the "naked regulators" config and leaving everything else as described in the build guide. This should give you 15V for the Burson V6, and take full advantage of the SparkOS regulators.
If you're going to use discrete regulators and opamps, you'll probably be best going with the "naked regulators" config and leaving everything else as described in the build guide. This should give you 15V for the Burson V6, and take full advantage of the SparkOS regulators.