Salas hotrodded blue DCB1 build - Page 216 - diyAudio
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Old 23rd August 2012, 01:39 AM   #2151
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Quote:
Originally Posted by Salas View Post
Those with 0Vgs towards the audio part of the board nearer to 5 Leds each. Use thermal paste and check them well for good insulation pads and good but not overt tightness.
Ok, makes sense as I think those were the two that had gotten a little loose. Thanks Salas.
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Old 23rd August 2012, 01:40 AM   #2152
Salas is offline Salas  Greece
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Let us know, I hope the sinking is enough for 1A yes? 1A means 20W dissipation per rail constantly for DCB1 usual voltages across the power semis.
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Old 23rd August 2012, 01:45 AM   #2153
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I will. It may not be enough actually. I am going to back down to 600ma or so until I figure out a proper solution.
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Old 23rd August 2012, 01:55 AM   #2154
syklab is offline syklab  Hong Kong
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Originally Posted by wushuliu View Post
I will. It may not be enough actually. I am going to back down to 600ma or so until I figure out a proper solution.
Hi,
What are you using for the current setting resistor?

Thanks
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Old 23rd August 2012, 01:58 AM   #2155
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1R
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Old 23rd August 2012, 02:11 PM   #2156
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Salas,

what toroid would be preferable if I go for 1.2-1.5A version?
-80VA 2x15V
-100VA 2x12V
-100VA 2x17V

I would personally stay with 80VA toroid as it would be easier to install in the case I found.

Also would these outer heatsinks be enough for 1.5A version?

Tea-Bag,
got the board, thank you very much!
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Old 23rd August 2012, 03:48 PM   #2157
AndrewT is offline AndrewT  Scotland
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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.
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Last edited by AndrewT; 23rd August 2012 at 03:51 PM.
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Old 23rd August 2012, 04:19 PM   #2158
palmito is offline palmito  United States
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For people who are running their dcb1 at 1Adc or higher, is there a marked improvement in subjective sound quality from running the board at 1Adc (and above) versus ~600mA?
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Old 23rd August 2012, 05:04 PM   #2159
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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.
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Old 24th August 2012, 07:17 AM   #2160
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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?

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.
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