Salas hotrodded blue DCB1 build

Jump to Latest
#3,862
Measured voltage drops across the current setting resistors are OK, do DC mV offset measurement across each audio output also. To post a picture press the "Go Advanced" button under the reply frame and use the "Manage Attachments" menu.
 
#3,863

Attachments

  • DSC00754.jpg
    DSC00754.jpg
    580.4 KB · Views: 342
#3,864
Looks very well put together. But don't run it for more than minutes without sinking on a metal surface or real sinks at this current setting. Don't forget it needs insulation pads on the MOSFETS backs when you will do the sinking. To know DC offset you just need the DMM on DCmV range with black probe on center pin of the out Molex and red probe to L, then to R.
 
#3,866
You got no DCmV range on the DMM I assume. Its still low enough an indication even if possibly rough. Concludes that the relay makes contact, the buffer circuits are alive, and the outputs are safe for connection to an audio system.
 
#3,868
I would like to thank Salas, Tea-Bag, Wushuliu, Nezblu and the other contributors to this forum for their assistance in getting me to this stage. I am certain I will have more questions when it comes to wiring etc. so i will be in touch. Thanks again.
Mark
 
#3,871
Andrew,
So sources such as cd/dvd which are high level and can drive many amps directly have no need of a buffer. These sources would merely need an attenuator to reduce volume to a tolerable level. Low level sources like phono will make use of the buffer?
Overall, it's the craziest thing, but I'm not certain I know what I built or how to use it properly. Please explain so even a non audio person can understand.
 
Last edited:
#3,872
Taken from the group buy thread, when the topic diverged to CLC prefiltering:

Salas said:
Any you may find among a range of available chokes in your budget frame that has as much parasitic resistance for as much voltage you need to drop. 7-10VDC Vin to DCB1 reg higher than its 10VDC output must be left. Find a free utility named Duncan PSUD2 and simulate all your parameters. For load use your DCB1 current setting. For possible further questions on this matter, better continue in the DCB1 thread. Its too long a specialized discussion for the GB thread.
Click to expand...

To use the choke, the boards would have to be modified so that the choke could sit between the two 4700 uF caps. ie. cut the trace.

As for DCR, most any air core chokes intended for speaker use, should do the job. Like maybe an 2 mH ERSE with 18 AWG wiring.

Would this interfere with the output impedance of the power supply?
 
#3,878
mbain said:
Could you please elaborate on what you used and how you assembled it.
Click to expand...

Its a typical implementation. From input RCA to pot, to DCB1 in. You use the DCB1 as a pot buffer for all of your sources. You will need a switch before the pot if you have more than one source. Any relevant configuration copied from switching sources and wiring a pot in front of say a valve preamp will do. We normally use up to 25K pot for faster rise time with the JFET type found in the DCB1.
 
#3,880
That is a 10K input amp, yes? For driving it as an impedance its good. But I see 17dB gain in that amp which means it won't help go much loud without extra gain in the preamp if the source isn't strong and the speakers aren't sensitive. Any buffer is a unity gain stage. Will play averagely loud but will not bring it to full with a phono as source for example. With a DAC, OK.
 
You must log in or register to reply here.
Top Bottom