Salas hotrodded blue DCB1 build

diyAudio Chief Moderator
Joined 2002
Paid Member
Salas, if i want to adapt the power supply used in DCB1 for +/- 5V what changes i need to do ? The source used in RIAA preamp seem a bit simpler but is as effective as this one used in DCB1 ?
Sorry if i am a but offtopic but lost between your threads.

Adrian

You should use 2 leds and a diode instead of 5 leds and it will give you 5V if you must, but BIB is better for a general reg.
 
DCB1

Happy to report I have hooked it up to my second system and it is now statring the burn in process. Sounding pretty darn nice. :spin:

After burn in I will bring it in and take a listen on my main system. Then more than likely go to 600ma or more and upgrade to TX resistors. And report back.

At that point I will put in enclosure.

Nice project! Thanks Salas and Tea Bag
 
Member
Joined 2008
Paid Member
Not sure. What caught me first was a slight smell of burning after about 30 seconds. I actually got a few seconds of music then it cut out and that's when I checked and saw the leds were out. I did discover afterwards some of the fets had become a little loose - the bolts needing more tightening.

Which fets need replacing?
 
not the 12Vac.
the 17Vac may require so much heatsinking that the chassis packaging becomes unmanageable.
That leaves you with the 80VA 15+15Vac. The maximum continuous output current is ~ 1.3Adc
You will be running the transformer at it's full maximum rating continuously if you draw 1.3Adc from the rectifiers.

You will be overloading the transformer if you draw 1.4Adc or 1.5Adc from that 80VA transformer.

If you really want 1.4A to 1.5A from the CCS Shunt regulator, then I recommend a 160VA to 200VA, 15+15Vac transformer and enormous heatsinks to dissipate the current loading.
 
Last edited:
From Salas:
Stage 0 = circa 75-85mA Ecological and cool. Smart car territory, the twin 47R 1W marked on the Blue and no or mini sinks will do.

Stage 1 = circa 200mA. Boosted enough, all purpose, some logical sinks. Standard Blue HR, Golf GTI territory. 4W dissipation per rail. 10R 5W.

Stage 2 = circa 600mA. Increased grip and pull back, Porsche stuff. 12W dissipation per rail. Sinks like for a 30W class A/B amp. 3R3 5W.

Stage 3 = circa 2A. No holds sense, Enzo feel. 40W dissipation per rail. F5 size sinks & Tx. 1R 12W.
 
AndrewT

thank you!
I've finished reading the whole thread and found that you've already adviced using a transformer for hot rod version not more than 50% of it's nominal, could you please eleborate a bit why is that? What could be the consequences except additional heat if I try to draw a currnet of 2A from 2.66A toroid? :confused:

I've already done several projects where I used encapsulated square and toroid transformers up to 85% of their nominal ampere rating. The only problem I found is the heat - it raises up to 50 c...

will the case be able to cope with heating if I go for 1.3A? I have found the calculation earlier in the thread but actually do not understand all the parameters there.

palmito

not sure what page but it was reported here that there is an improvement if you go for >=1A version, though it's not so noticeable as if you go from 200 to 600mA.