Tripath Input Coupling Caps

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Hi All,

Dave and Dweekie, I am glad the the VR MKT 1822s got reviewed too! If nothing else, regardless of which cap you choose for the Input Cap, these will, AT THE LEAST, be a great choice for Bypass Caps too!

They have a lot going for them, size, price, availability, etc.

Now the question.... What value formula will give the best results in the Input/Output cap application, 10%, 1% or other value of the main cap?

Dave, with the right Bypass Caps, you might also change the preferences of the already tested caps. Maybe the Obbligatos would be able to give you the best of both worlds bypassed. Analog sounding AND accurate and even more detailed. That would be an interesting experiment too!

Thanks!

Regards//Keith
 
Dc Coupling

The theAnononymous 1 provided the DC Coupling circuit provided for this test. To get the circuit properly integrated into the test bed took some work on my part. As it turned out I made the work for myself. I tried all too hard to make a very simple connection complex and convoluted. Once I KISSed (“Kept It Simple Stupid")the circuit worked like a charm.

This circuit replaces the input coupling capacitors in the AMP6 test bed amplifier. I had to do some minor setting of the DC voltage levels prior to testing. This took a couple of minutes with the aid of a multi-meter.

This circuit is by far the fastest most musical of the couplings I have tested. By this I mean everything seems so “precise”. I am hearing details in these test selections that I have not heard before with any capacitor. The dynamics of this coupling are spooky. The results are so life like. The quiet to loud passages and dynamics of instruments and vocalist just seem to be more realistic with the circuit than any of the caps I have tested.

The soundstage is holographic front to rear and broad side to side. The sound seems to come from well beyond the confines of the speakers. The ambiance of the recording venue is reproduced: large halls sound large, small studios sound small, and mixed recordings are clearly mixes.

This later (mixes) is the most discouraging phase of this test. Recordings that are mixed rather than recorded collectively sound “flat”. These recordings loose prospects of synthesizing a live performance. This is most noticeable on Takin’ It to The Streets by the Doobie Brothers. This coupling circuit made the performance sound clinical – much less enjoyable. I think this circuit may point up the “ant-tube” sound. Caps enhance the listening experience for recordings such as this.

Closely miked instruments made me have to re-evaluate the way I listened. On these recordings the musicians were much larger than life. I conduct all tests with the volume control at the same setting. This coupling allowed the AMP6 to play much louder which made closely miked recordings fatiguing after a while. If I opted to turn the volume down I am sure the fatigue level would subside, considerably.

The bass is neither fat nor lean. It is reproduces exactly the source. If anything the various colorations of some of the coupling capacitors are not there. The woody overtones of the acoustic bass just “kicks it!” The wood overtone of acoustic guitars is really apparent on the Mark O’Connor and James Taylor recordings. If anything, this coupling could be said to be analytical. Cymbals have that “ring” to them. That makes a cymbal a cymbal. It is not pronounced or etched. The placement of the cymbal varies from recording to recording, and you can clearly hear the different cymbal collections from drum kit to drum kit.

Violins have a silky quality. Brass instruments have that metallic tone. I know this sound best of all for I played trumpet at a time in my life and still have one I can blow just to A/B my system to a live trumpet. The Solen (Solens Review ( Post#69)) sound of the highs is here but tempered and moderated to the setting of the recording engineer. There is no sibilance on female vocals and the Mark O’Connor Tiger Rag is listenable.

The use of this circuit is a step beyond swapping caps. It requires auxilliary power supplies above those used for the amplifier and some time to set the voltage levels. For those daring enough to Do-It-Yourself the original thread is: DC Coupling.

Although, this circuit has created a tremendous amount of listening satisfaction; it has created another set of variables that might be tweaked. Changing the discrete components of this circuit may alter the sound just as the various capacitors have in these tests. Then you add in power supplies, voltage regulation, etc. and there maybe an entire another realm of coupling possibilities.

I have lived with this set up for the last 4 days to see if my impressions changed over time. The only thing is the less desirable effects on mixed recordings as noted above.

I plan to integrate this circuit into the overall test bed which will allow me to compare the circuit to coupling capacitors. Only in the event I hear something that is profoundly different from the above will I post another write up.
 
Man you make me curious.
Replacing a simple capacitor by some OpAmps sounds so contrary to my findings so far. My experience until now was to remove as much active circuitry as possible.
I will test it out soon.
What source have you been using for the tests?

This circuit seems to be a dream match for AKM dacs as they sound fantastic if they feed the coupling caps without any components in between.

What if the OPA123 are replaced with better OpAmps?
And what if a dedicated PS is used to feed them?
Tweaking potential is there no doubt.

I got everything here to test it, but my source is still not fixed, bummer.

Thanks Dave for the extensive work you do!

Greets,
Klaus
 
Radian said:
What source have you been using for the tests?

What if the OPA123 are replaced with better OpAmps?
And what if a dedicated PS is used to feed them?

I am using a tweaked Samsung DVD player, this goes into the AMP6. The test bed is described in detail on page 1 and subsequently. The music sources/selections are listed on page 2 post #29.

Lostcause said:
If you can keep the power supplies seperate and there is no DC coming in from your source then give it a try.

For the DC coupling circuit I am using a separate SMPS for the coupling circuit. The AC for the SMPS comes from a dedicated line. The test bed and DVD player are on another circuit. The DVD player gets its AC via a JR/Felicia power conditioner.

I am really interested in the prospects of DC Coupling, but I think if we are going to get into the specifics of the how and whys we need to start a separate thread.
 
Based on the generally positive comments about the stock Bennic caps in the Trends TA 10.1 I haven't considered any mods.

However, on opening mine up to change the jumper settings to make it a power amp, I discovered it doesn't have Bennics! It was purchased about 2 months ago and is definitely branded as a 10.1 version.

Can anyone identify what these are and how they compare to Bennics.

Thanks.
 

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DC Coupling Part II

I have added the DC Coupling circuit as one of the poles on the rotary switch of my test bed, This allowed me to switch between caps and the circuit.

The coupling circuit, undoubtedly, plays much louder than any of the capacitors. For those who may desire a little more umph from there T-Amps you may want to consider this circuit. In addition, the soundstage is wider and deeper than any of the capacitors.

The circuit sounds "clearer" than the caps to my ears in my system. However, YMMV.
 
Hi all,
Just spotted this thread and thought I would throw in my own experience with a Trends TA10.1.
The amp came with yellow caps that don't say Bennic on them but are apparently Bennic XPP unbranded. I have no clue. The amp has performed fantastically but I have always experienced some mid range harshness on some recordings which i attributed to speakers which are new or the NOS DAC also new. To cut a long story short I moved the output coupling caps which are 1 microfarad Vitamin Q from The DAC into the amp to replace the "Bennics". The result was astounding, huge soundstage, greater air and life, much better bass, improved dynamics and zero harshness.
In this process I have removed a cap completely which I am sure has helped a lot but the Sprague vitamin Q in the amp works really well. They are way too big physically but with some work they fit in the amp casing nicely. Cost of these caps was 11.50 Euro each.
I am not sure of the necessity of 2.2 microfarad as my 1 seems ok. Maybe someone can advise as I could always parallel 2 caps as I can only get them up to 1 microfarad.
Robin
 
Bypass Phase !

I set up my test bed to test bypass capacitors for the Tripath input capacitors. I had considered building an addendum to the test bed for this test, but I rigged it up to get a test off as quickly as possible.

I have Blackgate 2.2 μf 50 volt PK series electrolytic capacitors hard wired to the input terminals of the Amp6. The leads from the rotary switch are wired in parallel to these caps. This gives me the capacity to switch in various bypass capacitors via the rotary switch. Blackgate technical notes do not recommend that their capacitors be bypassed.

I, initially, tried a 0.01 μf cap (I believe it to be either a film or silver mica). I neither heard any difference in the highs as noted by Radian nor did I hear any difference in the rest of the musical presentation. Radian used much smaller caps for the bypass, which may account for what he heard.

I then switched in the 0.1 μf Flourinert capacitor provided by Serengetiplains. I did not hear any difference with this cap switched in as the bypass either. I will try a 0.1 μf Russian Teflon cap to compare to the Flourinert capacitor.

I suspect that the value of bypass cap in this application may be to large. I will try some smaller value caps later this week to see if I do hear a difference bypassing Panasonic FC electrolytic caps.
 
Hi Dave,

With all the extra wire and distance added in the circuit, the results might not be so apparent. It may matter less with the big cap but the amaller bypass cap supposedly gets affected because this is where the faster transients seem to pass through. I believe when bypassing and maybe with coupling caps too, the rule with the wire and connection distance is, "Less is More."

The shortest distance to your amp with the main cap and the bypass cap and they "should" be attached to the circuit at the same two points. Parallel with the legs attached to the same two points.
I know this makes testing a pain but this probably would be the fairest way to really judge if they truly make a difference.

Now this is just my opinion and hearsay as I never actually tested this. You and the other guys probably know better if this makes a real difference. I am very interested in this subject and hope you can get the most accurate results! There is a member in the Forum that is a strong proponent of Bypassing Caps, "Eva" has done a lot of work with this and has some very interesting views and explanations.

BTW, FWIW the values I read most are either 1/10 and 1/100 of the main cap value and sometimes 1/200.

I hope all is well!

Regards//Keith
 
Hi,
I am new here, although I have followed various subjects in the last year, I never engaged, so I am under moderation. I was/am interested in contacting Serengetiplains about flourinert in coupling caps but now I am intrigued with Davet and his Dc coupling circuit. Could this work with the Winsome Labs amp based on the tripath 2050 chip? This is my first and only T-amp and I realley like it although it would benefit from some mods.
Gary
 
DC Coupling Circuit

The DC Coupling circuit I am using is on loan to me by theAnononymous 1. I am sure the circuit will work in place of any input cap. Mods and the like will have to be taken up with theAnononymous 1.

Regarding flourinert, you will have to take that up with Serengetiplains. I would suggest you contact him, directly, via email. I had to send him the Russian Teflon caps for him to work his magic on. He then sent them back to me. The foregoing is just to let you know what I did to get the flourinert caps.

Now that "we" are engaged ;) - you can let your hair down.
 
KP11520 said:
Hi Dave,

With all the extra wire and distance added in the circuit, the results might not be so apparent. It may matter less with the big cap but the smaller bypass cap supposedly gets affected because this is where the faster transients seem to pass through. I believe when bypassing and maybe with coupling caps too, the rule with the wire and connection distance is, "Less is More."

The shortest distance to your amp with the main cap and the bypass cap and they "should" be attached to the circuit at the same two points. Parallel with the legs attached to the same two points.
I know this makes testing a pain but this probably would be the fairest way to really judge if they truly make a difference.

BTW, FWIW the values I read most are either 1/10 and 1/100 of the main cap value and sometimes 1/200.

I hope all is well!

Regards//Keith

I will try the silver mica cap connected directly where the electrolytic is connected. I agree, less is more Considering the small size of the electrolytic it is going to take a bit of effort on my part to tack solder
bypass caps to their leads. This becomes a daunting task when trying to connect the Russian caps.

The bypass value is going to be based on the caps I have on hand. The 0.1 μf, 0.01 μf, 0.001 μf, etc. The first bypass value is 5% of the 2.2 μf electrolytic. I may well have caps that exactly meet the 10% rule, but that will not work for the flourinert caps. So the test will be what it is for the moment. Maybe at a later time I will try to adhere to more conventional practices.
 
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