Salas hotrodded blue DCB1 build - Page 382 - diyAudio
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Old 21st February 2014, 11:02 PM   #3811
Salas is offline Salas  Greece
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Quote:
Originally Posted by Scorpion View Post
Thanks Salas, that clear things up a lot.

Btw, I was thinking about using big Siemens/Epcos Sikorel 125°C or SIC-SAFCO Felsic Capax in the PSU for their very high quality, reliability, excellent sound and very low ESR... but since both models are screw-terminal types, I guess I would end up with increased resistance (from routing wires from caps to board). Is there any way to counteract or to lower this effect ?

Of course, I would keep wire lenghts to a minimum and keep your advice to max capacitance of 10 000uf X2 per side B+ B-

I was thinking about using very high voltage caps (350v) because the higher the voltage the lower the ESR...Also had the idea to link big 200uf @350V SCR aluminum metallized polypropylene caps as "current drawing caps" to the Sikorel or SIC-SAFCO in order to lower ESR even further (big SCR have ESR OF 1,3 !!!).

In fact, would like to imitate the way PSU are built by Audiomat (known for the excellence of their PSU and their exquisite sound quality). My source is composed of Audiomat D1 drive and Maestro 2 DAC....love them both. Had Audiomat Opera Reference before and loved it too.

Would it be feasible/logical in the DCB1 context ? I am willing to build the aluminum enclosure to allow required space to fit the hig caps.

Please see the following links for Audiomat:
6moons audio reviews: Audiomat Opéra Référence
AUDIOMAT MAESTRO REFERENCE | Convertisseurs | Audiomat
Audiomat Récital MKIV

The following link for SCR (look for PC20000AL capacitor when from pdf file at bottom of page:
AC capacitors with aluminium enclosure | SCR

The following for SIC-SAFCO Felsic Capax (pdf file...look for 10000uf @350-450V):
Screw terminals

And for Epcos Sikorel (pdf 125°C):
EPCOS - Capacitors with Screw Terminals - Aluminum Electrolytic Capacitors - Capacitors - Product Catalog - Technical Parameter - Product Search - Products - Home


Sorry if there are some mistakes here and there as english is not my first language (french is).

Regards

Scorpion
Big PSU capacitor components and parallels will null the relative PCB arrangement for the snap in ones and will necessarily introduce cabling. It will be an outside from PCB arrangement and I can't predict its impact. Naturally it will work but if its worth the trouble you will be the one to judge since I only used snap in on board as everybody here without an exemption that I can remember. Side to side square profile cables can be better for inter cap and to board connections with less inductive impedance than loose wide ones.
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Old 22nd February 2014, 08:32 AM   #3812
AndrewT is offline AndrewT  Scotland
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I mentioned that one of my DCB1 boards had rCRC fitted ON THE BOARD.
You did not pick up on that.
It clearly shows less ripple being fed to the regulator.
But I cannot hear any difference in the sound output.
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Old 22nd February 2014, 11:59 AM   #3813
mantha3 is offline mantha3  United States
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I'm powering an LED lit power switch off of the LED position on the PCB with the arrow pointed to it. I am going to not run this LED power switch off of this spot now. Do I need to put a PCB LED in this spot or can I just leave this LED spot empty without issue?

Click the image to open in full size.
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Old 22nd February 2014, 12:34 PM   #3814
Salas is offline Salas  Greece
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You can leave it unpopulated without issue.
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Old 22nd February 2014, 01:18 PM   #3815
mantha3 is offline mantha3  United States
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Thank you Salas

I can't tell you how much I appreciate your time in helping me along the way. My DCB1 is 6 months old and kicks A$$
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Old 22nd February 2014, 03:42 PM   #3816
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Quote:
Originally Posted by AndrewT View Post
I mentioned that one of my DCB1 boards had rCRC fitted ON THE BOARD.
You did not pick up on that.
It clearly shows less ripple being fed to the regulator.
But I cannot hear any difference in the sound output.
Thanks for your answer Andrew T. You are right, I did not pick up on that. With so many posts, I guess I missed/skipped that part.

Btw, excuse my ignorance but what is a rCRC ?

Since you said you didn't hear differences in sound from less ripple to regulator, I am wondering if I might not be complicating stuff for nothing i.e going trough the hassles of building an external PSU with top specs like super low ESR...but also introducing higher inductive impedance from these extra cables, as pointed out by Salas.

Again, thank you for your time.

Sincere regards.

Scorpion
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Old 22nd February 2014, 05:42 PM   #3817
AndrewT is offline AndrewT  Scotland
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The regulator makes a pretty good job of isolating the amplifier/buffer from the changes/interference coming in from the mains.

For that reason one should not expect a good regulator to show a big improvement by improving the quality of the DC coming from the smoothing & rectifier.

An lm317 is a poor regulator especially at HF and this generally shows a big measurable improvement when less ripple is fed to the chip. So big that it is usually audible.

I would not expect that to happen with the DCB1. But the experiment was worthwhile.

RC is a filter.
rC is a filter.
rCRC is a cascaded filter.
The r is the transformer and wiring and rectifier resistance.
The first C is the first smoothing capacitor.
The R is the added resistor between the two capacitors.
The last C is the main supply of transient current to feed changes in current demand.
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Last edited by AndrewT; 22nd February 2014 at 05:45 PM.
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Old 26th February 2014, 01:30 PM   #3818
ghiglie is offline ghiglie  Italy
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Hello,
I'm planning this build starting from an old kit a friend forgot on a shelf. I admit... I'm totally noob! I tried to scan this thread, but I couldn't find an answer.
I'd use a 16Vx2 trafo, used in commond with the volume/input selector board. Is it enough for a slightly hotrodded build?
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Old 26th February 2014, 01:33 PM   #3819
Salas is offline Salas  Greece
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If it is 30-50VA also.
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Old 26th February 2014, 04:02 PM   #3820
ghiglie is offline ghiglie  Italy
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Thanks Salas. There are lots of builds around the net, with many different implementations - very interesting but sometimes confusing for DIY n00bs.
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