Salas hotrodded blue DCB1 build

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#1,561
buzzforb said:
The heatsink is overkill. I could probably mount directly to 1/16" bottom and be fine. Did it to try higher bias setting. Will try higher bias soon.

I am reminded of John Curl talking abbout how much time he put into his psu and regulatr section. This makes me a beliver.
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The sink ain't overkill if you will pass 1A CCS. I had used up to 2A in T-Amp, gets hot. Is your mains trafo capable? DCB1 is a combo thing ''tuned'' to its supply to my subjective liking, so yes, the audio-psu-pcb combo is not exactly a B1 in practice (subjective performance wise). Has its own traits and how you run its PSU lends a mark.
 
#1,562
I know it differs from B1 if for no other reason that it is symmetrical. This in itself is interestig, but add the shunt and you got something special. 1A is only 250 mA away and these babies are only lukewarm. In my BA output, I am running 3A and 25V rails on these same sinks. Trafo is cheapo RS at 12.6-0-12.6 and 2A. Quiet as mouse ar 750mA.
 
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#1,563
The supply is symmetrical so to avoid couplers, not the audio part, that one is the same SE thing. Passing the 1A line step by step the sink will prove OK to already have. Spending 10V @ 1.5A per rail is 15W per shunt Mosfet dissipation for instance, now add the CCS Mosfets at that current times their voltage drop In-out...
 
#1,565
buzzforb said:
1A is only 250 mA away and these babies are only lukewarm.
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now turn the input voltage up to match maximum mains supply voltage stated by your supplier.
Is the heatsink lukewarm?

Now accidentally short the output of the regulator and determine whether the CCS mosFET can survive and for how long.
Did you manage to turn off the power before you melted the CCS mosFET?

Now combine both those operational conditions to create the somewhat rare but conceivable worst case operational condition.
Did the CCS mosFET melt?

If the CCS mosFET did not survive, what would be the consequent damage downstream?
 
#1,566
Salas said:
The supply is symmetrical so to avoid couplers, not the audio part, that one is the same SE thing. Passing the 1A line step by step the sink will prove OK to already have. Spending 10V @ 1.5A per rail is 15W per shunt Mosfet dissipation for instance, now add the CCS Mosfets at that current times their voltage drop In-out...
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Understood. I meant to reference the PSU as being symmetrical. My fault. I can easily encase the heatsinks in a large enclosure if I like the higher bias more. I made a mistake in my calculations on current bias. IT is 400mA not 750. Vdrop on Rs is .815mV/2R =.408mA. I will be paralleling 2R 3W resistors next to get to about .8mA. If the difference is as noticable as the first jump, I can't wait.


Tea-Bag said:
Buzz, I would get a 100VA 15v Antek for a trafo. (IMO)
Some people ran into problems with the RS-trafo's if I remember earlier builds correctly.

Looks good.:smash:
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I plan to. These are just for setup, but have performed fine. I have Antek in all my poweramps and pre's.
 
#1,567
Hi! Any comments about my questions below? Looks like everyone is excited about the 750ma and huge heatsink and my post got buried quickly.. Sorry for the boring questions 😛

hsiaobig said:
Hi All,
My preamp just went dead recently and I'm considering building a DCB1 as my new preamp. I currently have a UCD400 power amp. Do you think a balanced DCB1->UCD400 would be a good combination? I have searched several threads but seemed not see this combination in any discussion... Please let me know if you think there might be any problem with them.
Also, I have an UCD softstart module that I plan to use on DCB1. Would there be any problem in doing so? Thanks a lot!
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#1,568
I certainly don't remember anybody showing such a combination here, so this rather explains why nobody answered. Its a 26dB gain balanced hi-power module, seems operating just like a normal balanced input amp. You may ask the guys who make it if it will have any issues with a minimal offset dc coupled buffer pre-amp.
 
#1,569
I have spent the last couple of hours listening at 650mA and then 1A. The improvement is not as great a leap as going from 20mA to 400, but is better. 650 was better but nuanced, 1A brought more of evrything. The best way i know to describe it would be to say that it seems like the music played with greater ease with each step up. Its as if i am adding gain, but of course this untrue. You get more music at the same volume level, with things getting smoother with more detail. I dont knoe if you would call thi sincreased dynamics or what, but it is there. Heatsink still dont get very warm, so they can be downsized and maintain control. Fets are sitting at 32C and sinks right above fet at 34C. I will be using this type reg on all my preamps based on what i am hearing. Phenominal Salas!:worship:
 
#1,571
Noob Help for Hyponotize DCB1 Black

Hi everyone

Sorry for noobie question here….
I just finish up the build Hypnotize Black version

But first three LEDS light up fine(both Channels) but second Five LEDS(both channels) not lit up and regulated voltage is +18.3V and 18.3V…(Im using Hammond 12-0-12 2AFor testing) seems like regulator does not work properly… using 10ohm resistors for current limiting…

I checked LEDs polarity several times… and others like TR and resistors too… Relay works fine

I checked each five LEDS banks and it lit up fine individually, but not lit up all five LEDS altogether.

I really appreciate any help
Thanks
John
 
#1,574
Maybe you miss 1 Ohm resistors or simply jumper links where it has a resistor symbol with ''1'' in it?
 

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#1,578
If your relay clicks, regulator voltages are around 10V each and the DC offset on output is good, I don't see any grounds for it had suffered possible damage. Let us know how it went and post a picture also if possible when it will test alright.
 
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