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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
devinplombier
1,650 posts
 

@rubjel 

My suggestion to you is to purchase two more AirTight ATM-300s and recap each one with, respectively, Duelund CAST cu sn tinned copper, Jupiter copper foil paper and wax, and V-cap ODAM, and conduct rigorous A/B/C listening sessions. Only this way can you pick a winner with any semblance of objectivity.

This is actually interesting; please be sure sure to come back and report your findings.

Or, you can listen to the advice of @rauliruegas who, if I’m not mistaken, has credentials and experience reaching far, far beyond any of the sources you say you’ve used in your research thus far. What you ultimately decide is, of course, your choice.

Good luck, and Happy Listening! 

 

Post removed 
johnss
679 posts
 

@rubjel , I have tried all 3 of the caps mentioned. All are very good. Very organic sounding. 

Would offer the following. 

1. if your amp does not have a ton of ventilation or runs a hot chassis the Jupiter may not be the best option since they do not do well in high heat. 

2. the Dueland cast copper are super nice but physically very large. You may want to measure the area these caps occupy and make sure you have enough room to squeeze them in. 

with the voltage ratings most are available at 100VDC for speaker use or 600VDC for tube electronics use. 

I don't think you will go wrong with any of your three selections. 

 

antigrunge2
1,564 posts
 

Japanese tube amp designers take great care evaluating each component in extensive listening tests. Replacing them with other specs seems a non obvious way to improve their sound

rauliruegas
13,347 posts
 

Der @logistics ​@devinplombier    :

 

A capacitor has to has firt than all neutral resolution ( audio ) and must be trusty under any electronics/crossover condition during play and does not change when temperature changes and in all electronics always are changing.

Designers do not use as " equalizers " but as cap that is neutral and bullet proof.

Knowledge Base - WIMA – Competence in Capacitors

Here we can read main caps information.

 

I'm using mainly the FKP 1 and MKP 10.

 

R.

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