AirTight ATM-300 - new Coupling Caps

Dear @devinplombier  : I'm with you. No cap is totally neutral and electrolitic cap behavior is diffirent that the film ones.

In the case offf my speakers that are really old/vintge ADS L2030 ( fantastic silk dome drivers in the tweeters and mid ranges,. ADS made its own drivers in all its speakers but the 2030 that were made in exculive for ADS by a Germany manufacturer. ) ) the crossover original caps for the woofers were an electrolitic ones ( 100uf. ) There are several alternatives coming from Sprague, Vishay, Kemet and the like . Instead I choosed film caps Wima MKP10 wired in parallel to achieve 100uf and performs better than ever but we have to consider that I'm talking of the bass frequency  range where what you said you just can't be aware of it ..

R.

@rubjel , Tinned copper Duelands. 

The othere cap that is very organic but no longer made is the Jensen copper foil caps. Very organic sounding cap. Jensen was bought out by a conglomerate who discontinued these caps. 

As long as you are in there you can also take a look at the plate resistors on the input tubes. Most are either carbon or flame proof metal oxide used for reliability. 

I replaced them with higher wattage MiLLs wire wound audio grade. You will lower the noise floor a few db as well. 

"So better quality input PS caps will also provide better SQ, this will get expensive :)"

quite so and one of the main reasons they are not offered as OEM. 

Being an individual reintroduced to 300B Amp design in both PP and SE over the past two years and hearing designs with Interstage Tranx's and Coupling Cap's, the experiences had changed a long term dislike I harboured towards such a Valve Amp.  

I was left with an impression which resulted in my purchasing a 300B SE Amp'.

Off Topic:

With the now available options for myself to have experiences of different 300B Valves. There is now known a substantial difference is able to be produced within an End Sound when different Valve Brands are being used in a 300B Amp'. 

I am confident in the suggestion a lot can be achieved towards betterment of the End Sound when Valve Brands are also being considered.

I am confident in the suggestion a lot can be achieved towards betterment of the End Sound when the Amplifier is mounted on pneumatic footers, and even more betterment is on offer if a Resin Impregnated Densified Wood Board is used as a  Sub-Plinth for the Amp'.

Dear @salectric  :

x-over.jpg (800×533)

You can see in this crossover speaker at least 5 different capacitor models and that crossover goes insida 250+K speakers.

Yes all those different caps in the same speaker could says that the designer used the caps as " tone /eq/ passive devices looking for a higher quality that maybe the speakers has not and certainly all those caps are only spreading full colorations/distortions.

16092016c.jpg (800×533)

TID9142-13.jpg (1920×751)

Well for a gentleman with the knowledge levels you have all those is self explained and confirm what I posted. Of course that I can be wrong but I'm only sharing first hand experiences.

R.