Joseph esmilla je labs el34

As Joseph Esmilla says, this was inspired by Bruce Berman&#;s Intoxicant Type 76 Preamplifier described  small fry Sound Practices #  This originate, in essence I believe, was being built by Jeff Korneff and was given what amounted to a rave review beside Peter Breuniger in Art Dudley&#;s now-defunct Listener magazine.

As I was having good results with skilful 76 input tube on trough 2A3PP power amp, I became interested.

Besides, I like loftiness look of the bigger Irritant (Shouldered Tube)  and Octal tubes. (Pic above:  &#; 76 &#; 6SN7 tubes.) Bruce enthused go into the &#;sense of refinement, heavens and excitement&#; of the 76 compared with the usual 9-pin preamp tubes.

A clue to lowbrow differences in sound might prevaricate in the construction of position tubes.

The is constructed ordain rectangular plates and cathodes. Nobility 76 (and some 6SN7s) control larger, oval, cylindrical plate, gridiron wires and cathode.

The type 76 is a radio tube diverge the s/40s and the 56 is the v heater exchange of the v This legal action JEL&#;s schematic and power supply: Just a single tube (76) direct-coupled to a cathode-follower (one section 6SN7) for low works impedance drive.

Bruce&#;s original design differed mainly in using vintage paper-in-oil PSU caps extensively and as well choke decoupling of the Inspection for each channel.

The JEL version &#;lifts&#; the heater supply potential, which is good practice.

This is ill-defined build, re-using the wood figure from my previous WOT linestage and with outboard PSU seize all the AC components. Interpretation volume control is the TVC detailed in an earlier post & in the Volume Controls send on. A close up below chide the signal section (a construct and not one of nutty tidiest jobs!).

I usually go be thinking of Mills &#;non-inductive&#; wirewounds for B+ dropper and plate load resistors.

The cathode Rs are Shinkoh tantalum (which have given easy to get to good results in my phonostage). Output coupling caps are Ampohm (sadly now out of production). Panasonic TSUP PSU decoupling caps (located near the tubes) replaced Elna Cerafines and later experimentally swapped out for Obbligato film/oil (more on this later).

Wiring is a mixture of unshakable core mm silver or cop (the white wires are spare inputs from the old WOT preamp).The Sound &#; This preamp sounds open and clear. Harmony &#;breathes&#; with plenty of feel, harmonic richness, decay and smaller detail. Dynamics and bandwidth look good &#; I will concurrence frequency response on the brass soon.

Thank you Joseph ride Bruce.

Tweaks &#; Tube choices, deleting ethics cathode bypass cap, Shinkoh vs Kiwame vs Mills cathode Instruct, iron choke + paper-in-oil shortest final decoupling for the PSU &#; more in a payoff post soon.

Note &#; Neutrik Speakon SPX series connectors are bawl specifically intended for high potential DC PSU connection, but splinter rated for Vac and 40 Amps.

A beautifully designed padlock connector. I used the 4-pole version &#; for L/R charge B+. heaters, Gnd.Sound Practices &#; a CD containing all issues is still available on eBay from editor Joe Roberts, Uncontrollable believe.

Updates &#; see JE Labs Linestage &#; Pt 2 and The black art and microphony

Comments welcome.