KABOOM!
"I have some Elna Cerafine 100uF / 25V ROA series. Can I use those somewhere in my gainclone? Like bypassing the 1000uF standard caps I use...?"
I would not put 25V caps on a 35 Volt supply in less you put two in series with a 10K resistor divider to half the voltage across them. I tried 100uF Cerafines across some Nichicons and was pretty unhappy with the sound. I don't understand the cult following that the Cerafines have. A designer who's ears I trust descrided them as "Shouty". I found them grainy and veiled sounding sounding as supply bypass caps. The Black gate 100uF Stadard series sound like a completely different amp and were much so better at high frequency focus and dynamic contrast.
I think even the Panasonic FC might be an improvement over Cerafines.
"I have some Elna Cerafine 100uF / 25V ROA series. Can I use those somewhere in my gainclone? Like bypassing the 1000uF standard caps I use...?"
I would not put 25V caps on a 35 Volt supply in less you put two in series with a 10K resistor divider to half the voltage across them. I tried 100uF Cerafines across some Nichicons and was pretty unhappy with the sound. I don't understand the cult following that the Cerafines have. A designer who's ears I trust descrided them as "Shouty". I found them grainy and veiled sounding sounding as supply bypass caps. The Black gate 100uF Stadard series sound like a completely different amp and were much so better at high frequency focus and dynamic contrast.
I think even the Panasonic FC might be an improvement over Cerafines.
Re: KABOOM!
Thanks.
I have never heard those Cerafines in any application myself, just wondered if they could do something nice for my gc. I'll drop the idea and in fact I'm really happy with my gc as it sounds now...
Can I follow-up here:
My gc is three-channel poweramp, and I want to expand it into a five-channel version to be used as combined stereo and cinema amp.
This one uses standard Jamicon 1000uF caps. I want to make those two extra channels better than the other three channels, since I'll be using them for stereo on a regular basis.
However I cannot at the moment afford to buy those Black Gates.
Are there any alternatives to BG 1000uf? Would those Panasonic FC's be the best bet?
Fred Dieckmann said:
Thanks.
I have never heard those Cerafines in any application myself, just wondered if they could do something nice for my gc. I'll drop the idea and in fact I'm really happy with my gc as it sounds now...
Can I follow-up here:
My gc is three-channel poweramp, and I want to expand it into a five-channel version to be used as combined stereo and cinema amp.
This one uses standard Jamicon 1000uF caps. I want to make those two extra channels better than the other three channels, since I'll be using them for stereo on a regular basis.
However I cannot at the moment afford to buy those Black Gates.
Are there any alternatives to BG 1000uf? Would those Panasonic FC's be the best bet?
I tested the amp with a friend's oscilloscope
on a dummy 5R load (made with 2 1/4W 10R resistors) the signal is nice clean
even when we push the volume, the signal is clean.
at 100% volums it was still clean, untill the 1/4W resistor began to smoke (it didn't like 40W 
)
the power supply lines have 25V DC, plus an AC signal, like sawtooth, but with a vertical section and a non vertical one, 300mV p-p, 100Hz
some noise on the output, with no signal, but <20mV
now the bad part of the news:
when connected to a speaker, and a sinusoid denerator (computer based (the computer's output is a clean sinudoid)
the signal is good at low volume, but at higher volume, the sine's top peak is a big filled circle
on a dummy 5R load (made with 2 1/4W 10R resistors) the signal is nice clean
even when we push the volume, the signal is clean.
at 100% volums it was still clean, untill the 1/4W resistor began to smoke
(it didn't like 40W )the power supply lines have 25V DC, plus an AC signal, like sawtooth, but with a vertical section and a non vertical one, 300mV p-p, 100Hz
some noise on the output, with no signal, but <20mV
now the bad part of the news:
when connected to a speaker, and a sinusoid denerator (computer based (the computer's output is a clean sinudoid)
the signal is good at low volume, but at higher volume, the sine's top peak is a big filled circle
Bricolo said:Why do WIMA MKS4 sound bad?
I've got a pair of MKS2 4.7uF laying here, waiting for being soldered to my gainclone's input
don't tell me they don't sound good, I payed them 3€ one
Hmmm... I paid around 20 eurocent for my 2.2 uF MKS4 I think. And I think it sucks more or less. Well, I just don't like it. MKC4 is much better, and very probably MKP10 too. Sorry...
But maybe MKS2 is good... just try it!
Fedde
Snubbing DC Supplies.
There is much good information here by the likes of Peter, Fred and many others regarding sonic influence of transformers, rectifiers, caps, diode snubbing networks etc..
One tweak that I have utilised in the past is to put RC snubbing networks across the main supplies.
I found this to noticeably 'quieten' the amplifiers that I tried it on.
Eric.
There is much good information here by the likes of Peter, Fred and many others regarding sonic influence of transformers, rectifiers, caps, diode snubbing networks etc..
One tweak that I have utilised in the past is to put RC snubbing networks across the main supplies.
I found this to noticeably 'quieten' the amplifiers that I tried it on.
Eric.
I was recently sent some of these (47 mfd/50v) for free as the supplier was unable to supply my original request for Silmics! I don't know if that indicates that they are considered poor enough to give away or not.
I have used the Cerafines as DC blockers on the inputs of my two stereo power amps and have an arrangement that allows me to swap them in or out of circuit.
To be honest, I can't hear when they are in or out of circuit which, to me, indicates that they are not bad although I appreciate that they may not be so 'transparent' in a more critical part of the circuit.
Hi!
Since it is sometimes hard to get Wima MKP10 in low voltage ratings with higher capacitance (like 4.7uF), one can always check out the MKP caps from speaker networks. Visaton in Germany even has MKP caps in the Wima MKP style (in a nice black finish), a lot cheaper than Mundorf and the likings (but I have yet to fire up my P3A with Visaton input cap, so I can't tell how they sound right now ).
And try omitting the cap from the circuit, if there's no high DC offset at the output, you can leave it out... (btw, I am wondering why I have - without input cap - about 9 mV DC on one IC, and 61 mV on the other, both have completely the same setup, and resistors are ultra-precision Welwyn RC55 (0.1 %) ????)
Bye,
Arndt
fedde said:
Since it is sometimes hard to get Wima MKP10 in low voltage ratings with higher capacitance (like 4.7uF), one can always check out the MKP caps from speaker networks. Visaton in Germany even has MKP caps in the Wima MKP style (in a nice black finish), a lot cheaper than Mundorf and the likings (but I have yet to fire up my P3A with Visaton input cap, so I can't tell how they sound right now
).And try omitting the cap from the circuit, if there's no high DC offset at the output, you can leave it out... (btw, I am wondering why I have - without input cap - about 9 mV DC on one IC, and 61 mV on the other, both have completely the same setup, and resistors are ultra-precision Welwyn RC55 (0.1 %)
????)Bye,
Arndt
gainclones
Hi
I don't mean to be sarcastic in any way at all. I've looked at the schematics for the Gaincard and those of many of the gainclones. I don't see a substantial difference between them and the schematics for an op-amp. I mean aside from changes in resistor values, etc... the basic layout is the same in all. Is there a patent for the Gaincard.
Now, don't take this message the wrong way. I am glad to see that people are not snubbing technology. I have nothing at all aginst IC chips for quality audio. I believe that it is the quality of the product not the esoterica that matters. If a simple amp can be built with a high quality chip then so be it. In fact, I will eventually build a gainclone myself. I am happy that good quality audio can be DIY'd for so little cost.
Also, what do people thick of the schematics that are available in the application notes at the National Semiconductor site (www.national.com)?
Could someone please shed some light in this for me.
Thank you,
vic
Hi
I don't mean to be sarcastic in any way at all. I've looked at the schematics for the Gaincard and those of many of the gainclones. I don't see a substantial difference between them and the schematics for an op-amp. I mean aside from changes in resistor values, etc... the basic layout is the same in all. Is there a patent for the Gaincard.
Now, don't take this message the wrong way. I am glad to see that people are not snubbing technology. I have nothing at all aginst IC chips for quality audio. I believe that it is the quality of the product not the esoterica that matters. If a simple amp can be built with a high quality chip then so be it. In fact, I will eventually build a gainclone myself. I am happy that good quality audio can be DIY'd for so little cost.
Also, what do people thick of the schematics that are available in the application notes at the National Semiconductor site (www.national.com)?
Could someone please shed some light in this for me.
Thank you,
vic
Hi!
The original GainCard actually is kind of a simplified version of the application circuit from National. 47labs sinply left out some parts. The only thing where they might claim having done somethin unique are the deliberate undersized supply caps. But I don't think that that alone qualifies for copyrights on the schematics...
So, yes, it is a kind of free design. And since the LM3875 IS an op-amp, you won't see any great differences to normal op-amp applications...
And the modifications made in this and another forum were simply changing the design from non-inverting amplifier to inverting amplifier, and again omitting some parts which don't necessarily have to be used (depending on some factors, pre-amplifier, cables etc.). And the rest is pure tweaking, with different brands for parts (including the op-amp itself), and some basic layout tweaking, and probably the nicest thing, building beautiful casings for the GC which make people like me green with envy...
Bye,
Arndt
The original GainCard actually is kind of a simplified version of the application circuit from National. 47labs sinply left out some parts. The only thing where they might claim having done somethin unique are the deliberate undersized supply caps. But I don't think that that alone qualifies for copyrights on the schematics...
So, yes, it is a kind of free design. And since the LM3875 IS an op-amp, you won't see any great differences to normal op-amp applications...
And the modifications made in this and another forum were simply changing the design from non-inverting amplifier to inverting amplifier, and again omitting some parts which don't necessarily have to be used (depending on some factors, pre-amplifier, cables etc.). And the rest is pure tweaking, with different brands for parts (including the op-amp itself), and some basic layout tweaking, and probably the nicest thing, building beautiful casings for the GC which make people like me green with envy...
Bye,
Arndt
Matt, as a rule the voltage rating of the capacitor should be 1.25 the voltage on the rail.
If your rails are 25 volts then the capacitor rating should be 1.25 times that which would be 31.25 volts so you lowest you would use would be rated at 35 volts.
If you are using a 25-0-25 v transformer then your rails will be around 36 volts and your caps should be rated for at least 45 volts (hence the 50 volt rating that most people use).
deandob said:
Hi Dean,
The snubbers I refer to were acros the DC supplies, and from memory 10 ohms in series with 100.11111 uF.
This gave subjectively nice damped quality to the overall sound.
In future I will do more scientific tests to discern resonances of the DC power rails, and probably apply additional LCR shunt networks, but at the time these RC shunt snubbers had good sonic effect.
Eric.
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