Tekton Double Impacts

Hi all, I just wanted to briefly outline the scope of Tom's 300B SET build. It will be a single chassis stereo amplifier, using dual 5U4G rectifiers (both in parallel to provide double the current capacity), and a 6SN7 per channel for the input and driver stages. Single capacitor coupled output to the 300B, running the 300B at 66% dissipation for longevity and to produce 8 watts per channel. A choke-filtered power supply, and robust filter stages after the rectifier will produce a very black background. In addition each 300B will have its own independent filament transformer. DC on the 6SN7 filaments will provide low noise for the input/driver stages and reduce the overall noise floor to nil (generally not an easy task for a 300B based amplifier). All power resistors will use Vishay chassis-mount/heat sinked units to reduce internal heat, and essentially the entire amp will be built to provide twice the current that the circuit requires for lower heat/better reliability. The amplifier weighs close to 50 lbs, and will be 17" wide x 12" deep, x 3" tall (minus the wooden side rails). Price is $3,600 including EH 300B power tubes, (2) Sylvania NOS 5U4G's, and (2) RCA 6SN7GTB's for the drivers. 2 year warranty on the amplifier as well. 

Hi Aric,
Thanks for the additional information.  This custom made 300b  amplifier driving the Double Impact SE will be a fantastic pairing is my prediction. 

Do you have an opinion regarding electrolytic versus "film" capacitors in the power supply (filtration) and is one inherently better than the other ?
Charles 

Jay, the speakers are 6' o.c. with the listening position about 8' from the speakers. 

Thanks for the recommendations Greg and Charles. I have some new CDs to look forward to Monday now.

thanks Aric, you explained the amp build far better than I ever could! There are many here that will understand the build much better than I as their informed questions will demonstrate......as Charles has already demonstrated.

tom

Hey Charles, you're very welcome! With regards to filter stages, I am a believer in using good quality electrolytic bypassed with a high quality metalized polypropylene. To get a film capacitor of the correct UF ratings to effectively smooth ripple, size restraints come into play. Good low ESR caps can make for a very quiet power supply circuit. Aric

I also wanted to add that in any build I undertake, I like to maintain a "form flows function" approach (and also follow the KISS rule), by keeping all power circuitry towards the rear of the amp near the AC inlet, and all signal paths towards the front and/or out to the sides. Then find the average operational points of the tubes, and design around that. Use transformers rated for at least 33% more than the duty cycles of the circuits.Then the use of high quality parts come into play (the sum of the parts gives a synergy- much like the blend of a good recipe), keep wiring paths short (twisting filament wiring to cancel AC fields, shielding signal wiring wherever it may encroach a power circuit, etc.). Lastly isolate the chassis from audio and signal grounds and use a star/single point termination for the ground reference. I’ve found that maintaining all of these aspects in any build yields a reliable and typically a great sounding piece of gear.