Salas hotrodded blue DCB1 build

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#2,642
Salas said:
*If someone is perfectionist about matching the Verf LED gangs of 5, the best maniac party trick is to use a *12V battery, connect gate and source together in the specific 2SK170s that are going to feed those strings (those Jfets above 1R), feed (+) to the drain, connect g&s node to LEDS string, return string's other end to (-), and swap between enough glow bugs until you got 2 total across 5 LEDS Voltage matches, each to its own Jfet. For the cherry on the cake set DVM that measures diode drop (some got it) and find 2 Vbe matched BC550 & 560.
Practical benefit? Next to nothing. Aesthetic ritualistic benefit? Priceless.😀

*9V,1.5V,1.5V batteries in series that are common types, maybe already in remote controls on the coffee table, will do for 12V total. And don't post pics from the parking space tapping on the car's stuff.🙂
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I might think sometimes that you shouldnt tell thise maniac partytricks because one day someone might take you seriously Salas. Ofcourse I'm just posting those pix educationally to what could happen if someone really took you seriously.




Staffan
 
#2,644
Salas said:
Good choices.

If you really got space in the box, I would recommend 4 monstrous 2.2uF Russian capacitors to make two 4.4uF pairs bypassing each pair with 0.1uF monstrous Russian Teflon. I believe they exceed the German silver in oil type even when in that config for far far less.
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Salas

I replaced obbligato premium gold 4.7 uF with K75 only 2.2 uF (no place for other 2.2 uF) bypassed FT-3 0.1 In my coupling application - I get enough bass do you recommend to use other 2.2 cap with FT-3 0.1
there are imrovement In highs but I think that the sound Is somehow aggresive and In your face - can that effect be fixed when caps get burned In
 
#2,645
That combination is smooth, weighty, and transparent in my experience. What is the amp and speakers you play music with? To better quantify the caps signature to your liking and system tonal synergy let the K75 play alone, just lift one link to each FT-3. What are the perceived changes? K75 alone is rather rounder and darker. If the tone is still upfront you may need match your former uF value first to say for sure.
 
#2,649
There is gain then. Which is good for F5 on your speakers. OK do the K75 alone test first. Some combination should work best for you. Do you see space for your Obbli plus the K75 in your box for another experiment with higher coupling uF value?
 
#2,653
I can't hear burn in for non electrolytics. Never could. Maybe you got a resonance with leads in the bypass. Using wires? Try 0.1-0.22R in series with the FT-3 bypass before one leg meeting the respective K75's leg.
 
#2,657
Salas said:
It won't. Their transconductance is near enough.
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Thanks Salas. I soldered them in yesterday along with some other stuff. When I came to the filtercaps I noticed that I had got 25 V filtercaps on the GB, which made me a little worried since there is going to be around 21ish VDC camelbacks straight into them.

So, as a big box of heatsinks also arrived yesterday, I came up with the idea of leaving the rectifiers out of the cards and make a centralized one, followed by a pre C-R (2 big caps and 8 separate 5-10 R resistors, one for each rail, sending fairly smoothed DC to the double 4700 uF caps as last separate C's.

What DC is to be aimed at over the last filterlyts (b4 the 10 R current setting resistor)?

Staffan
 
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#2,659
Phew. Drilling and threading 32 M3s pulls me to the dark side. It took almost 3 sixpacks and in the end I was almost in to the ethyl alcohol. But now sits here 4 stuffed boards.

I did some measures feeding them 1 by 1 by the trafo and two 5R6 ( closer to 5R5 actually) on the rectified plus and minus.


Im gonna try make a chart. First column is card, 1, second card 2 etc:

Voltage drop 5R5:.....0,988/1,260.......0,910/1,183......0,979/1,194.....0,975/1,188

Makes current mA:....180/229.............165/215...........178/217..........177/216

Vout buffer (-/+):.....10,01/9,98........10,11/10,09........10,08/10,04...10,07/10,05

First is negative rail, second is positive on all above.

DC offset L/R mA:......0,3/1,1...............0,7/1,6............0,04/2,8.........1,5/2,2

So, positive takes more current then negative but outputs slightly less Vout.

What does the Jedi Council say. Am I still with the rebels or should I go talk to the man in the mask (I.e. do you think I should plug it in)?

Staffan
 
#2,660
Jedi says the force is with you. The photon swords are functioning safely. Main CCS differences are due to PMOS/NMOS Vgs differences. Offsets are great. Due to big sinks are used you can experiment at a point to know if more hot rod rocks your planet better or not. 25% smaller setter for positive can give more balanced CCS with the benefit of hindsight if for newer current level test.

P.S. They give more for 5R6 usually. Maybe the VA is low and the input DC dropped?
 
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