@ Beardman
If you need more top attack in your system try with a 10k log volume potentiometer.
Salas, does this come at the expense of losing some mid and lower or does it just highlight the top end more? Or does it make the entire presentation seem clearer? Love to try it out but thought I ask first.
Thanks, nash
Salas, I'd like to understand how Beardman says that the OPA 2134 makes the top end more clear. It would seem to me that any opamp used in the servo section would only be a negative the aim being to get as small a negative as possible.
nash
Several operational amp chips in the servo position can possibly leave a detectable trace of their "DNA" behind. Bit of their THD, IMD, load damping, and self noise as integrators in other words. Beardman prefers a chip residual with little more sense of sparkle in his full system but he also recognized that the BOM's AD823 does not alter the raw preamp's tone when he compared it VS empty socket. So he is not without a compass, he is just salting his food to his own taste. Maybe marrying better with his TKD pot. Some other members reported hearing nothing when changing proper offset resulting op-amps types there in the past though.
Salas, does this come at the expense of losing some mid and lower or does it just highlight the top end more? Or does it make the entire presentation seem clearer? Love to try it out but thought I ask first.
Thanks, nash
Makes the whole presentation tilt to leaner and faster. Can feel cleaner if the total audio system's in room sound is rather heavy but can feel anxious if the in room sound is rather dry.
@Salas, that means that as we discussed earlier in the thread for my build I will be reusing the Salas BiB PSU boards (+/-IRF) with a 23-0-23v 1A (dual secondaries) RCORE transformer. So I got a 150R 5W load resistor for the BiB psu boards to set the voltage to +/-17V DC for the DCG3. Am I correct in assuming that the DC output voltage for DCG3 should be fixed at +/-17V?
Thanks
manniraj, where did you get the R core from?
Thanks, nash
No matter DCSTB or BiB or other PSU its output has to be set at +/- 17V as noted in the DCG3 schematic.
Thanks Salas, but using a 0-23V*2 1A RCORE with BiB @ +/-17V DC output may be over rated! Do you think regulators on the BiB board have to drop the voltage to 17v and hence more heat dissipation?
If you can manage for large heat sinking on the BiB's CCS MOSFET it will like the large voltage drop to sounding bit cleaner. But its mainly a waste of energy and torturing that MOSFET. Drop voltage on a power resistor by using external rectification and external first reservoir making CRC to the BiB's reservoir skipping its own diodes or use a lower output transformer.
18V-0-18V
The unorthodox solution not to leave your nice R-Core jobless would be change the preamp not to change the supply.
So use an EA2-24NU relay, jumper the three LEDS positions on the DCG3, use 18V Za, OPA2604 U1 and give it +/-21V DC rails from your BiB shunt regs.
The unorthodox solution not to leave your nice R-Core jobless would be change the preamp not to change the supply.
So use an EA2-24NU relay, jumper the three LEDS positions on the DCG3, use 18V Za, OPA2604 U1 and give it +/-21V DC rails from your BiB shunt regs.
18V-0-18V
The unorthodox solution not to leave your nice R-Core jobless would be change the preamp not to change the supply.
So use an EA2-24NU relay, jumper the three LEDS positions on the DCG3, use 18V Za, OPA2604 U1 and give it +/-21V DC rails from your BiB shunt regs.
Thats asking too much from a non-techie like me to do I haven't got any clue of what you mentioned above with only understanding of using jumpers on the LEDs on the DCG3 board. Also if usng 18-0-18v does 1A current is sufficient?
Yep 1A rating is sufficient. If not for two transformers but for one shared between channels make it 1.75A
Something like this should be fine I think.
115V 230V 50W R Core Transformer 18V+18V 9V+9V for Audio Amplifier Preamps AMP DAC R Core-in Transformers from Home Improvement on Aliexpress.com | Alibaba Group
If you live in India try to buy Shilchar. Their R-Core is what the French Selectronic used to distribute under own brand name. Very good proven stuff. Should be cheaper domestically. Contact them they may tell you of retailers: Shilchar Technologies Ltd.
For +/- BiB reg you need four wire (two independent 18V secondaries) because BiB has two bridges between polarities.
DCSTB can work with either three wire 18-0-18 or with four wire 18+18 when connecting the middle wires together.
For +/- BiB reg you need four wire (two independent 18V secondaries) because BiB has two bridges between polarities.
DCSTB can work with either three wire 18-0-18 or with four wire 18+18 when connecting the middle wires together.
Thanks Salas, I never knew about this company making RCOREs but not sure if they do local retails sales 1 or 2 orders. I have mailed them lets see if they come back and agree, otherwise I will go ahead with Aliexpress as looking at the price of $25 including shipping the difference getting it locally or China more or less the same except if I am unlucky then the customs charges need to be borne extra. I have asked for couple of transformers with the following ratings, keeping in mind I may venture into dual mono psu's
0-230v Primary
0-18v @ 500mA
0-18v @ 500mA
Quantity of 2 with the same ratings RCORE.
0-230v Primary
0-18v @ 500mA
0-18v @ 500mA
Quantity of 2 with the same ratings RCORE.
They don't primarily categorize by current spec in the factories. They go by core sizes and secondary voltages to create a gamut of models. Then they test each voltage + VA combination and characterize it for current also. Because R-Core runs cool either ask Shilchar for two 40VA units if planning double mono or for one 70VA unit if planning for one common transformer and one common regulator between channels.
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