PS decoupling caps in Gainclone - Page 2

huy5005 · 13th January 2009, 12:23 AM

Try with 20hz tone, measure the supply rail voltage if you have voltage fluctuation, then your need larger cap or larger power supply or regulated power supply which provides enough current for the amp.

raypalmer · 13th January 2009, 04:06 AM

Has anyone found any significant improvement jumping from the 1500 Panny FC caps to a higher value panny fc? 3300 etc....

ClaveFremen · 13th January 2009, 06:37 AM

Quote:

Originally posted by huy5005
Try with 20hz tone, measure the supply rail voltage if you have voltage fluctuation, then your need larger cap or larger power supply or regulated power supply which provides enough current for the amp.

Interesting!

Nice Idea the 20Hz Tone but 10000uf +100uf isn't enough?

(see photos from first post)

Next test session I would give it a try!

Quote:

Originally posted by raypalmer
Has anyone found any significant improvement jumping from the 1500 Panny FC caps to a higher value panny fc? 3300 etc....

Aren't you referring to values of Peter Daniel's kits'reservoir/smoothing caps?

Mine is from BrianGT so reservoir/smoothing caps are 10000uF!

Or you refer to 100uF PS decoupling caps?

ClaveFremen · 14th January 2009, 11:29 PM

Quote:

Originally posted by mikesnowdon
I think I will build a diy amp from scratch soon and Im quite keen on the chipamp.com kits. How does yours compare to other amps you have tried?

Quote:

Originally posted by ClaveFremen

Answering you question:

well, it maybe sounds a little better than my modded marantz receiver (in this moment it is still the pre) but I have to swap back speakers to the Marantz to say for sure!

Well, yesterday I branched again my Marantz receiver to the front speakers...

The difference is HUGE: the Marantz is bit more polite with highs (a bit of harshness less) but soundstage is a lot smaller, particularly in depth, basses are less controlled, channel separation is in another league (thanks dual-mono!!) and there is quite less dynamic.

Conclusions:

- My Gainclone is a big improvement over the power amp section of my Marantz receiver.
- Small values bypass of good electrolythics isn't always the best thing after sliced bread...in this case they're a detriment of sound quality.

mikesnowdon · 15th January 2009, 04:07 PM

Hi Dario.

Were the different caps you tried all the same value's?

ClaveFremen · 15th January 2009, 04:37 PM

Quote:

Originally posted by mikesnowdon
Hi Dario.

Were the different caps you tried all the same value's?

Yes.

100uF 50V for the Elcos and 0,1uf for film bypasses.

I've ordered some Wimas MKP2 0,1uF from Germany. I think they will arrive at the end of next week.

I want to try some different bypass caps... MMKs and Epcos were not good there.

If someone had good results with others 0,5mm led spacing bypass caps not too costly I would try them.

huy5005 · 16th January 2009, 09:13 PM

Do you have voltage fluctuation at the supply rail?

For the cap, i tried with so many different caps. The larger cap will make the beauty of mid and high disappear. In fact, Panasonic FC 1500 cap is a good choice when you have a large transformer (larger cap doesn't help the bass though for my case). I think the bass issue is the problem of amp and speaker matching. if you want, you can try Carolsm snubbed power supply which i found that it is excellent with small transformer and picky speakers. Don't forget to check Peter's threads 'cause he has done so many experiments perhaps,, drop him a line

ClaveFremen · 16th January 2009, 10:26 PM

Quote:

Originally posted by huy5005
Do you have voltage fluctuation at the supply rail?

For the cap, i tried with so many different caps. The larger cap will make the beauty of mid and high disappear. In fact, Panasonic FC 1500 cap is a good choice when you have a large transformer (larger cap doesn't help the bass though for my case). I think the bass issue is the problem of amp and speaker matching. if you want, you can try Carolsm snubbed power supply which i found that it is excellent with small transformer and picky speakers. Don't forget to check Peter's threads 'cause he has done so many experiments perhaps,, drop him a line

I've measured voltage fluctuations with a 20Hz sine tone and voltage varies from 33.16 and 33.19 Volts on V+, hence with 0.03 Volts variations (V- the same).

To me it seems OK, isn't it?

Your Gainclone is a kit from Peter Daniels or similar?

I asked you because mine is from BrianGT and includes Snubberized CarlosFM PS, Zobel Network, 10000uF smothing caps and 100uF Decoupling caps on chip rails.

huy5005 · 16th January 2009, 10:50 PM

That's very good. My kit is from Daniel.

With the 50% volume of sine 20hz from my sound card, my voltage drop down 1.50 volts V+ to gnd.

ClaveFremen · 16th January 2009, 11:28 PM

Quote:

Originally posted by huy5005
With the 50% volume of sine 20hz from my sound card, my voltage drop down 1.50 volts V+ to gnd.

Seems to me that we're talkink about different things

I've played the 20Hz tone and measured how V+ to gnd varies reproducing the tone.

With no music or tones V+ to gnd measures (V+ to gnd) 34.99 Volts, so it's a voltage drop of 1.80 Volts

I suspect you were talking about the second measure, isn't it?

13th January 2009, 04:06 AM	#12
raypalmer diyAudio Member Join Date: Dec 2008 Location: Burlington	Has anyone found any significant improvement jumping from the 1500 Panny FC caps to a higher value panny fc? 3300 etc.... __________________ Wherever you go there you are.

15th January 2009, 04:07 PM	#15
mikesnowdon diyAudio Member Join Date: Aug 2007	Hi Dario. Were the different caps you tried all the same value's? __________________ www.drugfreeworld.org

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13th January 2009, 12:23 AM	#11
huy5005 diyAudio Member Join Date: Dec 2007	Try with 20hz tone, measure the supply rail voltage if you have voltage fluctuation, then your need larger cap or larger power supply or regulated power supply which provides enough current for the amp.

16th January 2009, 09:13 PM	#17
huy5005 diyAudio Member Join Date: Dec 2007	Do you have voltage fluctuation at the supply rail? For the cap, i tried with so many different caps. The larger cap will make the beauty of mid and high disappear. In fact, Panasonic FC 1500 cap is a good choice when you have a large transformer (larger cap doesn't help the bass though for my case). I think the bass issue is the problem of amp and speaker matching. if you want, you can try Carolsm snubbed power supply which i found that it is excellent with small transformer and picky speakers. Don't forget to check Peter's threads 'cause he has done so many experiments perhaps,, drop him a line

16th January 2009, 10:50 PM	#19
huy5005 diyAudio Member Join Date: Dec 2007	That's very good. My kit is from Daniel. With the 50% volume of sine 20hz from my sound card, my voltage drop down 1.50 volts V+ to gnd.