Cap Coupled as a preamp / DC amp / Opinions

[Filip I]

Hey crew!

Just random brain farts here... Wanted to share my toughts with you,more experienced guys...

I am listening my 2000x while waiting for my AU 9500 to come back from the service. Nothing serious just some 726 noisy transistors... Main speakers are AR 5. ( Others are AR 17 and 18 )

Once back I plan to connect 2000x pre amp section and 9500 amp to see what' s flavour gonna be.

Just curios anybody did similiar combo? The thing is 2000x is just too weak to push AR ( normal listening levels are ok ). 9500 makes AR tottaly different animal for sure,more dynamics,details, bass is more defined. On the other hand 2000x as a Cap coupled design excel in soundstage, it has "flavour" that I realy like. Just has that romantic feeling...

So just trying to figure out does anyone had experience mixing CC as a preamp with other Sansui DC design?

I know this is, as anything in audio, very personal experience, just curious to see what you guys did and what was the result.

Thanks in advance for sharing your toughts and comments.

 

[HPMguy]

Should work fine. On the other hand I have a lot of modern amps that are cap coupled already -- 3.3 or 2.2 uF caps between pre-amp or tone controls and main amp.

Let us know what you think!

 

[Filip I]

Should work fine. On the other hand I have a lot of modern amps that are cap coupled already -- 3.3 or 2.2 uF caps between pre-amp or tone controls and main amp.

Let us know what you think!

Will do as soon as I get the 9500 back! I am not worried about the match, I know from the spec side all is good,more curious about the sound.Will it be more CC sound with the muscles or something else...

 

[JimEGR]

Hey crew!

So just trying to figure out does anyone had experience mixing CC as a preamp with other Sansui DC design?

I am still learning the design/engineering - are Capacitor Coupled and Direct Coupled (or even Transformer Coupled) integrated amps, pre-amps designed specific to the output type?

Look forward to reading about your AU-9500. So much lore and intrigue around that Sansui!

 

[HPMguy]

Not specifically the output, there are many places where a capacitor is used to "couple" stages rather than a direct wire, most often to block DC voltage from the next stage. Transformers do exactly the same thing, absolutely necessary in tube equipment because tubes REQUIRE a large voltage difference between cathode and anode to operate, often on the order of 250V and up. Adding this voltage to the signal will smoke the next stage whether it's part of the amplifier circuitry or the output.

Applying DC to speakers turns the voice coils into heating elements, with resultant smoke and or fire.

In solid state equipment, quasi-complimentary designs (meaning early ones) when matched pairs of NPN and PNP transistors didn't exist operated at an offset at half the "rail" voltage, again requiring a capacitor or transformer to block the DC voltage from the speakers or next stage.

DC coupled amps are fully balanced and at least when tone controls are switched out, there are no capacitors in the signal path from input to speakers.

Capacitors inherently distort the signal some, whether or not you prefer the sound that result compared to direct coupled amps is up to your ears.

 

[jd3rdcoast]

I'm guessing in this instance "cap coupled" refers to the final amplfier stage with DC filtering capacitors as the last components in the audio path before going to the speakers. They are in between the Output transistors and the Speaker terminals. That's where the "cap coupled sound" is created due to the "distortion" or "color" the capacitors add to the audio signal. Will be interesting to see what your experience is. My guess is it will have the tone of the DC amp.

 

[JimEGR]

QUOTE="jd3rdcoast, post: 16317903, member: 163877"]I'm guessing in this instance "cap coupled" refers to the final amplfier stage with DC filtering capacitors as the last components in the audio path before going to the speakers. They are in between the Output transistors and the Speaker terminals. That's where the "cap coupled sound" is created due to the "distortion" or "color" the capacitors add to the audio signal. Will be interesting to see what your experience is. My guess is it will have the tone of the DC amp.[/QUOTE]

This is what I was referring to, pre-amp design relating to the final. So integrated amp pre-amps are NOT designed specifically for the final output type - cap, direct, transformer. Thanks @jd3rdcoast @HPMguy.

And sorry to pull your thread a little off topic @Filip I - I think the discussion relates well enough though .

 

[Filip I]

@JimEGR not off the topic at all. Thank you all for sharing, disscusing.

I am just a simple guy who loves music and have a basic undestanding of electronics with tendency to explore and dig deeper.

So this disscusion is acctualy what I really hoped to be, to undestand what circuit,topology affect the sound. What gives overal sound its flavour. In simple terms my question was exactly what we are talking about. Is it pre amp sound what will determine sound. If those coupling capacitors in CC amps are excluded when the DC amp is included and CC amp is used as a preamp only.

I will definitively try this combo and report my experience. I am well familliar with the sound of both amplifier so I hope I will have some references to see how the sound is changed, is it more DC,is it more CC flavoured.

Meanwhile, please keep it running. Interested to hear what your experience is when pairing similiar equipment. Thanks a lot to you all.

 

[JimEGR]

@JimEGR not off the topic at all. Thank you all for sharing, disscusing.

I am just a simple guy who loves music and have a basic undestanding of electronics with tendency to explore and dig deeper.

So this disscusion is acctualy what I really hoped to be, to undestand what circuit,topology affect the sound. What gives overal sound its flavour. In simple terms my question was exactly what we are talking about. Is it pre amp sound what will determine sound. If those coupling capacitors in CC amps are excluded when the DC amp is included and CC amp is used as a preamp only.

I will definitively try this combo and report my experience. I am well familliar with the sound of both amplifier so I hope I will have some references to see how the sound is changed, is it more DC,is it more CC flavoured.

Meanwhile, please keep it running. Interested to hear what your experience is when pairing similiar equipment. Thanks a lot to you all.

Great. An excellent CC/DC discussion with a succinct post and comparative schematics by @dlucy here, too -
https://audiokarma.org/forums/index.php?threads/cap-coupled-vs-direct-coupled.947702/#post-15558536

 

[Filip I]

Reading your comments and links that you guys posted it's getting much clearer now what should I expect.Great explanations,great links,thanks.

Let me try and see if I got it figured: Since coupling capacitors are related to amp section ( and basicly they define that distinctive Cap coupled sound ), using 2000x as a preamp would exclude these from the chain, so probably gonna be more DC flavour. Remain to be seen...