ClaveFremen said:
here it's the same and not only for electronic components.
If you want something that it's not mainstream you must buy online...
Surely GB are interesting, particularly those like this one, for components you can buy online.
Peter and Uriah obviously deserves our gratitude
I've tried.
with tones is quite impossible...
With bass notes (AC/DC - Ride On and Bublé - Fever) at full volume (0db attenuation) at near field I would confirm my subjective impressions, differences are not night and day but audibles.
The 'body' of the note with R46 is not as big as DC coupled or PHE426, IMHO
You could try by yourself temporarily shorting C13att'n: only if you're SURE your pre/cd has NO DC OFFSET!!!! Measure it!
)
wich is the "Safe" DC Offset allowed fromPRE?
ClaveFremen said:You could try by yourself temporarily shorting C13
I've tried myself and simply shorting cap I can't hear any difference...
And it's right, a wire in parallel is like a cap of infinite value (circa), so the sonic signature of the real cap remain...
Only swapping caps or caps and wire differences are audible.
Sorry for the wrong information...
I am confused. While parallel capacitances are additive, shorting a capacitor takes it out, no? Just consider the fact that shorting it allows DC through, while otherwise DC would not go through. There is no chance for energy storage in the cap since the short keeps it from charging. What am I missing?ClaveFremen said:I've tried myself and simply shorting cap I can't hear any difference...
And it's right, a wire in parallel is like a cap of infinite value (circa), so the sonic signature of the real cap remain...
peter
having DC blocking caps in both the source and receiver is a complete waste.
You only need to block once.
Fit dual inputs to your power amp.
One RCA using the DC blocking cap, labeled AC input.
One RCA bypassing the DC blocker, labeled DC input.
The amp will still be AC coupled, due to the DC blocking cap in the NFB leg and the single DC blocking cap somewhere on the input.
This way you choose which is the better sounding cap, the one supplied as standard in your source (which can also be bypassed) or your very special and correctly sized one at your input.
You only need to block once.
Fit dual inputs to your power amp.
One RCA using the DC blocking cap, labeled AC input.
One RCA bypassing the DC blocker, labeled DC input.
The amp will still be AC coupled, due to the DC blocking cap in the NFB leg and the single DC blocking cap somewhere on the input.
This way you choose which is the better sounding cap, the one supplied as standard in your source (which can also be bypassed) or your very special and correctly sized one at your input.
schro20 said:
troystg said:
I'm confused too but I've tryed to short with a wire cap's leads on the breadboard and no difference were audible.
Putting wires from boards in the same breadboard line (no cap involved so) and difference from cap was audible.
I've explained that to myself in this way:
A (ideal) cap in signal path is a high-pass filter so, under the cutoff frequency is an open circuit and over a short circuit.
When you put a cap and a wire in parallel the wire let pass all the signal and the cap only the part over the cutoff frequency. The quantity of signal (over the cutoff frequency) is proportional to the esr of the cap and wire resistance.
In other words part of the signal pass through the shorted cap and so has its sound signature.
It could be right or I'm drunk?
Not a personal comment, please do not take it as anything directed personally.
Something must be amiss.
I still can't think of any frequency that a cap would have a lower resistance than a direct short. Therefore the majority of the signal (proportional to resistance of both paths) would take the short.
Something must be amiss.
I still can't think of any frequency that a cap would have a lower resistance than a direct short. Therefore the majority of the signal (proportional to resistance of both paths) would take the short.
There is an interesting article by Rod Elliott (surprise...) on caps. In particular he looks at all the parasitic effects just from soldering something and having longer leads and such and they dwarf everything else. That may well be what's going on in Dario's setup, since, as you point out, the behavior of a shorted capacitor with no other effects taking into account is unambiguous.troystg said:
peter
troystg said:
Troy, no problems at all.
apart how much of the signal passes through the cap one thing is sure:
a shorted cap is different from a wire...
Let's collect some data:
8 cm of 30AWG wire has a resistance of 0.0268 Ohms (my shorting cable was ca 8cm) (calculator)
I've found a CDE polypropilene cap that has a ESR of 0,012 Ohm...
A Panasonic FM Elco has ESRs as low as 0,012 Ohm...
With these values ca 2/3 of signal passes through the cap...
You are missing something.
You need a DC blocking cap if the amplifier is AC coupled.
You only need to block the DC once.
If you know that ALL your sources are already fitted with a DC blocking cap then you can omit the extra cap at the input to the power amplifier.
This is the expensive way to do it.
Each Blocking cap needs to be of sufficient quality for that source and needs to be correctly sized for any power amp that it gets connected to.
The economic alternative is to fit the correctly sized DC blocking cap to suit the power amp, inside the power amp and make it of a quality that suits you.
Adding a DC bypass allows you to choose which input to connect any other source, whether it has a DC blocking cap or DC servo or none.
You need a DC blocking cap if the amplifier is AC coupled.
You only need to block the DC once.
If you know that ALL your sources are already fitted with a DC blocking cap then you can omit the extra cap at the input to the power amplifier.
This is the expensive way to do it.
Each Blocking cap needs to be of sufficient quality for that source and needs to be correctly sized for any power amp that it gets connected to.
The economic alternative is to fit the correctly sized DC blocking cap to suit the power amp, inside the power amp and make it of a quality that suits you.
Adding a DC bypass allows you to choose which input to connect any other source, whether it has a DC blocking cap or DC servo or none.
Residual Hum
Hello again,
If I may pick your brains yet again, ------
Recall that after getting MyRef to work on both channels I had a serious hum.
This was reduced when joining transformer neutral outputs to ground.
Drastic further reduction was achieved by changing to monofilament wires between transformers and ampli and twisting them.
I thought that that had cured everything but in fact there is a residual hum that I could live with if necessary but I think you will understand that I would prefer to get rid of it completely.
Some observations:
A) The hum is very faint at normal volume settings and only increases perceptively in volume when the pot is turned right up way beyond normal listening setting.
B) Joining transformer neutral outputs to ground no longer has an effect. I can disconnect the ground and the hum stays but does not increase or decrease in volume.
C) If both interconnect cables Left and Right between CD player and ampli are disconnected, the hum disappears.
D) If the ampli input connections are then shorted, there is still no hum.
E) The hum is only present when both left and right channels are connected. If the left channel is disconnected, there is no longer any hum from either L or R speaker. Same if Right is disconnected.
Any suggestions ??
Hello again,
If I may pick your brains yet again, ------
Recall that after getting MyRef to work on both channels I had a serious hum.
This was reduced when joining transformer neutral outputs to ground.
Drastic further reduction was achieved by changing to monofilament wires between transformers and ampli and twisting them.
I thought that that had cured everything but in fact there is a residual hum that I could live with if necessary but I think you will understand that I would prefer to get rid of it completely.
Some observations:
A) The hum is very faint at normal volume settings and only increases perceptively in volume when the pot is turned right up way beyond normal listening setting.
B) Joining transformer neutral outputs to ground no longer has an effect. I can disconnect the ground and the hum stays but does not increase or decrease in volume.
C) If both interconnect cables Left and Right between CD player and ampli are disconnected, the hum disappears.
D) If the ampli input connections are then shorted, there is still no hum.
E) The hum is only present when both left and right channels are connected. If the left channel is disconnected, there is no longer any hum from either L or R speaker. Same if Right is disconnected.
Any suggestions ??
"D) If the ampli input connections are then shorted, there is still no hum.
E) The hum is only present when both left and right channels are connected. If the left channel is disconnected, there is no longer any hum from either L or R speaker. Same if Right is disconnected.
Any suggestions ??"
If shorting the inputs kills all hum it is not a AMP issue.
My suggestion is:
1) Tie the RCA grounds together at the source OR the amp.
2) Last resort is lift the cable ground on one channel and tie the AMP rca grounds together.
It is a ground loop of some sort.
Picture of the enclosure with rca inputs?
E) The hum is only present when both left and right channels are connected. If the left channel is disconnected, there is no longer any hum from either L or R speaker. Same if Right is disconnected.
Any suggestions ??"
If shorting the inputs kills all hum it is not a AMP issue.
My suggestion is:
1) Tie the RCA grounds together at the source OR the amp.
2) Last resort is lift the cable ground on one channel and tie the AMP rca grounds together.
It is a ground loop of some sort.
Picture of the enclosure with rca inputs?
DC Blocking Cap
Hi Andrew,
what you say makes sense. my question is regarding
the capacitor acutally being physcially close to the input
on the pcb vs. it on another unit. any affects?
electrically, audibly, it does not matter physically which
unit the dc blocking cap is on?
one high end cap on the output and a crappy cap on the input,
that is not good, so one cap makes sense.
thanks
Hi Andrew,
what you say makes sense. my question is regarding
the capacitor acutally being physcially close to the input
on the pcb vs. it on another unit. any affects?
electrically, audibly, it does not matter physically which
unit the dc blocking cap is on?
one high end cap on the output and a crappy cap on the input,
that is not good, so one cap makes sense.
thanks