AirTight ATM-300 - new Coupling Caps


So I want to replace the coupling caps in my Airtight 300B amp. The original ones are $5 Sprague orange drops. 0,1uF interstage caps between input tube (12AU7) and driver tube (12BH7A) and 0,47uF between driver tube and 300B.

I love the amplifier, it is very resolving and airy with great soundstage separation. However I miss some body and fullness, and tighter bass, hope new coupling caps can help with this. I like a natural sound with lots of body and texture, good detail and a tight and deep low end.

I have read alot of forum posts and narrowed my choices down to these 3;

Duelund CAST cu sn tinned copper

Jupiter copper foil paper and wax

V-cap ODAM

I have read that some capacitors are best used in lower voltage applications and others are better in higher voltage applications, so I am open to using different brands in interstage/300B coupling. 

Please share your experiences, impressions and recommendations. Not necessarily with the Airtight, but preferably used as a coupling cap.

rubjel

Perhaps, send a PM to Audiogon member, @grannyring.   He has extensive hands-on experience with many different brands of caps.

- - - 

A few months ago, I replaced ASC caps with AudioCap Thetas in my Concert Fidelity DAC-040BD.  A good decision.  More tone/timbre. More body.  More slam.  No loss of detail or air.    No downsides.

Also, consider V-Cap CuTF.    I have them in my tube preamp.  They’re very large for their values.  And take many hundreds of hours to burn-in.  But worth the wait.

Excellent advise @steakster, thank you :)

I mentioned grannyring in a previous post, I know he is one of the Grand Masters of capacitors around here, along with @salectric and probably others.

And thanks for your impressions, V-cap cutf has also been considered. However I have seen some reports saying it can be a bit thin sounding, but I guess it comes down to which components it is being used in.

Dear @rubjel   : " reports saying it can be a bit thin sounding "

 

" More tone/timbre. More body.  More slam.  No loss of detail or air.   "

 

By definition a capacitar needs not has" sound " by it self but dead neutral. A capacitor is no an eq.

Thinhgs are that I used the Teflon Cu V-caps as coupling and

was outperformed by the humble FKP1. This is a cap and the other are everything but a cap.

 

Fortunarelly I learned by first hand experiences and fortunatelly it's the OP who will uses it and not me.

 

R.

@rubjel 

I am not aware of anyone claiming copper V-Caps sound thin.  That might possibly apply to the original TFTF series but not the CuTF V-Caps.  The Copper V-Caps are warm and rich in the bass and have body for sure.  I have compared CuTF caps to Duelund CAST and TFTF many times and each time I preferred the CuTF.  I have not tried ODAM so I can’t how they compare.  ODAM might be a viable candidate where CuTF is too expensive, but that’s just speculation.  Another factor is long term reliability.  V-Caps have an excellent reputation for reliability as high-voltage coupling caps.  Having experienced failures of Jupiter and Vitamin caps, I put a high priority on reliability.

One final point.  When I built my current amps, I used Sprague coupling caps initially since I wasn’t sure how things would work out.  The Spragues were an inexpensive way to test the design.  After a few weeks I replaced them with CuTF couplers so I have an idea what you would hear with your Air Tights if you make the same swap.  The V-Caps sounded better in all respects and were a very worthwhile improvement.

@rauliruegas Yes, I noticed this sort of trend tends to apply to other items, such as power conditioners.  I was gifted what someone thought was a non-working UPS, but when I opened it later I realized was a hefty conditioner.  Turned out to be an Ametek PowerVar, which had large transformers and capacitors inside.  It immediately made my sound cleaner on my headphone listening rig.  Admittedly, my entire apartment runs on a single, 20 amp breaker running on old, cloth-covered hook and loop wiring in a 1940's house.  But its a beast compared to those 1U Furman units i see changing hands constantly, and they use them in hospitals and industry, rather than marketed towards audiophiles.