Dear @asa : well, some of us sometimes need to improve our ignorance level in audio.
R.
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.
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From my experience with the single-ended amplifiers that I built and modified, I realized that the requirements for "natural sound with lots of body and texture, good detail and a tight and deep low end" don’t exist. In fact, they are contradicting from one to others. The low distortion amps (without NFB) would have natural vocals which is thin with details and clarity. The bass would be tight, fast with details. On the other hand, it doesn’t boom at all that makes you fill thundery. Replacing the coupling capacitor would improve the distortion figure a bit but not much. I found that the 300B cathode bypass capacitor plays a much significant role. I replaced the cathode resistor and bypass capacitor with MOSFET shunt regulator which works like zener with adjustable voltage. Johnny |
Thanks Johnny @kmtang, I will definitely look into changing the cathode bypass capacitor and cathode resistor if I don't get the desired results after replacing the coupling caps. |
- 58 posts total