Yes, changing the caps on anything is usually not a big deal, technically. I just had a tech replace all of the PS caps in 2 Joule Electra pre's I still have around. But change is change....I think I have the 15ohm LS3/5As on the 8 ohm taps, sounds really nice, dreamy. I've had this system evolving for 35 yrs now and I can actually say at this point it is so involving that I just don't want to change anything, and that's a hard place to get to in this hobby/quest/obsession, if you know what I mean....that's probably where my reaction to your cap swap came from....on the GL 749s, you won't find anything out there, too rare these days, particularly as a matched pair, would be $2500+ if you ever saw them I'm sure...you really should, though, think about PC choices. It's not a radical change sound-wise on the amp but definitely worthwhile to look into. I had an Electraglide Fatboy on mine for years; very spacious, but a bit sluggish. A friend passed away and gave me the Siltech and it sounds nice on the amp; smooth, extended, dynamic, no weak points....it's atrociously expensive, though. And I just saw a Harmonix Takumi 1.5M PC sell on another site, my gut tells me that might sound good on the AirTight (I should have bought it myself, but I have too much gear around that I need to sell...)...just a thought. Let us know how the changes sound....
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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Dear @asa : Even with your " stomach " :
" whatever....It's not the caps, you'll have to trust me "
It depends where and wich caps, certainly your recomendation on those OIP goes with your statement or worse than that and " trust me on this. "
Btw, here you have a different " stomach " :
R. |
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 |
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