[ejfud]

Those look great Danny. Can't wait to build a pair.

[mlundy57]

me too, me too 

Mike

[Peter J]

Danny, can you elaborate on the RCA filter you mentioned? I know these as line level devices, is this on the speaker wiring? 

[Danny Richie]

Danny, can you elaborate on the RCA filter you mentioned? I know these as line level devices, is this on the speaker wiring?

It was a small Sonicap Platinum in an in-line RCA connector. It rolls off the bottom end.

[mlundy57]

Why wouldn't you put that on the inside?

Mike

[Danny Richie]

Why wouldn't you put that on the inside?

Mike

It plugs into the back of the amp.

[jcotner]

Do you have a firm arrival date on the first batch of drivers yet?
I have a road trip coming up that would allow for a diversion through
Iowa Park ,but would like to have a date to work with.

[Wig]

It plugs into the back of the amp.

Do I need an amp to use these on my desk top computer?

Wig

[jcotner]

Do I need an amp to use these on my desk top computer?

Wig

Yes. Lot's of talk about what amp to use and some guys wanting to put amps in the
boxes. You will need some sort of amp though. Danny is just designing drivers and
box(s) to put them in.

[Danny Richie]

Do you have a firm arrival date on the first batch of drivers yet?
I have a road trip coming up that would allow for a diversion through
Iowa Park ,but would like to have a date to work with.

The first production run is complete and leaves port on the 28th to head this way.

[mlundy57]

It plugs into the back of the amp.

Time for a demonstration of my ignorance. Does this filter plug into the input terminals of the amp, between the source (DAC) and the amp or into the speaker terminals?

Mike

[devinkato]

Time for a demonstration of my ignorance. Does this filter plug into the input terminals of the amp, between the source (DAC) and the amp or into the speaker terminals?

Mike

Between source and the amp.

[mlundy57]

Between source and the amp.

Thanks.

Why would you need/want to alter the input signal from the source rather than the output signal to the speakers?

Mike

[devinkato]

Thanks.

Why would you need/want to alter the input signal from the source rather than the output signal to the speakers?

Mike

Several reasons, mainly cheaper - it would require a component of much larger values to deal with the high level outputs.  Look up the cost for components to build a 80hz first order high pass crossover for a 4 or 8 ohm speaker.  Can be pretty pricy.

[Danny Richie]

Thanks.

Why would you need/want to alter the input signal from the source rather than the output signal to the speakers?

Mike

You can use something like this before the amp. This one actually has a by-pass, but you can make one without the by-pass.



This sounds good. A small value is needed to get the desired roll off. And since the value is small then you can use a high quality cap without spending a fortune. It keeps your amp from seeing any low frequency current demands increasing head room.

Doing it after the amp requires a big cap value. This can have a detrimental effect on the sound. It can also be a lot pricier.

[Danny Richie]

Several reasons, mainly cheaper - it would require a component of much larger values to deal with the high level outputs.  Look up the cost for components to build a 80hz first order high pass crossover for a 4 or 8 ohm speaker.  Can be pretty pricy.

You beat me to it.

Yep. 

[mlundy57]

You can use something like this before the amp. This one actually has a by-pass, but you can make one without the by-pass.



This sounds good. A small value is needed to get the desired roll off. And since the value is small then you can use a high quality cap without spending a fortune. It keeps your amp from seeing any low frequency current demands increasing head room.

Doing it after the amp requires a big cap value. This can have a detrimental effect on the sound. It can also be a lot pricier.

Would you still want to use something like that if you were running the speakers with a subwoofer?  Seems like it would defeat the purpose of the sub to strip the low frequencies out before the amp sees them.

How would it work best with this setup? My NAD C372 has two sets of preamp outputs and one set of power amp inputs. My DAC is connected to the "DISC" input channel. One of the pairs of preamp outputs is connected to the power amp inputs and the other pair of preamp outputs is connected to the sub.

Would you accomplish the same thing for the desktop speakers by connecting the RCA filter between the preamp out and the power amp in thereby still having the low frequency signal available for the sub via the other preamp output?

Alternately, if I used a sub with a PEQ amp could I connect the DAC to the line level inputs on the sub then connect the sub's high pass filter outputs to the amp for the desktop speaker? In this case, since the PEQ's high pass filter doesn't send anything below 80Hz to the amp would the inline RCA filter still be necessary?


If I am looking at the picture correctly I think I see another option. It looks like the DAC would connect to the filter's input. Then the male plug that is connected to the cap would be connected to the amp's input and the female plug that by-passes the cap would still be carrying the full signal and could be connected to the sub's line level input. Is that correct?

Mike

[Danny Richie]

Would you still want to use something like that if you were running the speakers with a subwoofer?  Seems like it would defeat the purpose of the sub to strip the low frequencies out before the amp sees them.

The sub-woofer doesn't strip out anything to the main speakers. Subs just cover the lower range only.

How would it work best with this setup? My NAD C372 has two sets of preamp outputs and one set of power amp inputs. My DAC is connected to the "DISC" input channel. One of the pairs of preamp outputs is connected to the power amp inputs and the other pair of preamp outputs is connected to the sub.

Send one set of outputs from your pre-amp to your sub and one set of outputs to a separate amp to power your main speakers. You can insert the inline filter on the inputs to the main amp. And then don't use the amp built into the unit. Basically you'd be using your integrated as a pre-amp. That is the only way to utilize a high pass inline filter like that.

Would you accomplish the same thing for the desktop speakers by connecting the RCA filter between the preamp out and the power amp in thereby still having the low frequency signal available for the sub via the other preamp output?

You mean looping your pre-amp out into the main amp input? Ah, that is a unique case, but might just work. If so then you could insert the filter there.

Alternately, if I used a sub with a PEQ amp could I connect the DAC to the line level inputs on the sub then connect the sub's high pass filter outputs to the amp for the desktop speaker?

No. For one, you wouldn't have a volume control. Secondly, never use a speaker level high pass out on those cheap plate amps. All they do is insert about a 100uF electrolytic cap into the signal path. That is the worst possible way to add a high pass filter. That will totally ruin the signal to the main speakers. 

In this case, since the PEQ's high pass filter doesn't send anything below 80Hz to the amp would the inline RCA filter still be necessary?

Nope, nope, don't use those at all. You'll be reducing the sound of you main speakers to the quality level of a clock radio when you do that.

[mlundy57]

Thanks Danny

Send one set of outputs from your pre-amp to your sub and one set of outputs to a separate amp to power your main speakers. You can insert the inline filter on the inputs to the main amp. And then don't use the amp built into the unit. Basically you'd be using your integrated as a pre-amp. That is the only way to utilize a high pass inline filter like that.

This is actually the way the NAD is made. It is an integrated only in that the preamp and power amp are physically in the same housing. They are not connected internally. You have to physically connect one of the sets of preamp outputs to a power amp. You can either connect the preamp to the 150wpc power amp that just happens to be co-located in the same housing (in which case you only need a very short pair of interconnects) or you can connect the preamp outputs to any other power amp you want (you'll need longer interconnects though).

Sounds like this is how I'll be doing it. I'll just have to get some more and longer interconnects.

I take it you need two filters, one for each channel, correct?

Mike

[Danny Richie]

I take it you need two filters, one for each channel, correct?

Yep, you need one for each channel.

Does NAD state the input impedance of the amp?