“Aspire” - Psvane 6SN7 globe preamp

 

After checking the expensive tubes of one of my preamps I'd sold to another one came up bad. I purchased the one good tube and helped the owner acquire replacements. I had a few parts on hand including the enclosure, most passive parts, ceramic socket, remote control Alps pot and the power tranni. Inverting the enclosure made assembly much easier and after some masking I sprayed back and top for good visual effect. The front is a natural silver frost, untouched.  

A mix of carbon and metal film make the resistive compliment and 5W wire wounds on the 4XPi HT filter. Two 1A diodes rectify the HT then 350uf of high voltage caps do the smoothing and storage. Cathode bi-pass caps are NP types and are bi-passed by 0.1uf polies.  Output caps are high grade audio polies and always sound excellent. Three inputs can be switched from the front and the preamp is silent in operation. Hookup wire is fine silver plated copper wire and WBT silver solder is used in the signal path. As always with these retro looking sphere/globe 6SN7s the sound is full bodies and transparent. Yet another well performing simple tube preamp and a good used of parts I've had for way too long. 

"Clarity II" - LJM Class AB power amp

 

This was a slow burn build. I had completed the amp section but no PS. After completing two commission jobs I could finally complete the amp. The compact enclosure for the amp was built around two heatsinks I had had for years and the enclosure for the PS the same. Caps standing out of the top of the PS I was given years ago and are Nippon Chemi-com. Total capacitance is not large but is well snubbed and the amp is quiet.

Two fast diodes provide rectification and four 3.3uf polies snub the bigger caps which are 3900uf each. Tranni is 160VA so the amp is capable of 80Wpc. The LJM Class AB modules used are rate 120W and are all bipolars. I like the sound of bipolar transistors and these modules contain nothing else and are very inexpensive. 

A local metals provider cut the plates for the amp to my specs and after a lot of drilling and tapping came together well. Three large gold plated brass cones balance the amp and add to the looks and improves the sound. An umbilical cord connects PS and amp using a large XLR connection. DC offset for these modules does not require adjustment and is extremely low.

The sound is super clear, detailed and expansive. Bass extends just beyond 30Hz the limit of my speakers. Regardless of type of music played it comes through, clear and uncluttered. After hours of listening the amp is still cold. I believe the amp would have no problems driving low efficiency difficult speakers. Very pleased with both the looks and the sound. 

German made EL3N - “Puissance” - triode strapped amp

 This time with a German made EL3N NOS NIB, new Svetlana 6N1P and Sylvania 5U4GB NOS NIB.

Interstage caps are Mundorf Supremes which I have used in a number of amps. Big and expensive but sound good. Hammond power tranni and Asian OPTs. The OPTs were meant to have the UL tap but didn’t. This amp then is triode strapped. Base is heavy and of blonde fine grain timber. Top plate is 2mm Al.

The EL3N sockets are made in Japan and are CNCed from a block of teflon with phosphor bronze contacts. Again expensive. PS is double Pi with 247uf of caps and a 5H choke. Total current drain is low and just over 20mA. The sound is big and warm with lots of drive. Though triode strapped it sounds very similar to my French tube SE UL version

6N3 + TDA7294 integrated amp.

A completed tube and chip integrated. Fast and crisp. Absolutely dead, dead quiet thanks to CMRR. 80Wpc, 300VA power tranni, choked power cord, rodium RCAs, RFI/EMI power filter, heavy duty speaker binding posts and 2U 19” rack mount. At the members request a low filter switchable cut of 6db at 150hZ. Also a 24 step step attenuator.