Welcome to the cool world of Tube Audio

Note that when great solid advice is given, certain reactions may manifest

"You are not generally upsetting a person, you are upsetting their programming"

TDoor  I - Hand crafted ShermanAudio amplifiers


Door II - Classic Tube Amp Restoration


Door III - My Loudspeaker Experiences

Door IV - "The Una-Tuber" Manifesto


Door V - Water Cooler


Door VI - e-mail


Door VII - Electrical Safety


Door VIII - Basics of Tube measurement


Door IX - Hammond-Leslie & Wurlitzer

(Partly under construction, I let a few things make it here)

Door X - Schematic Library

(Totally under construction now, your patience is very much appreciated)

Subjective "biased" Audio Power Tubes Opinions

KT-88/6550 - Cavernous lows & very polite highs, trash metal crunchers, surprisingly good with Horns and Lowthers

KT-66/6L6/5881* - Layered, tonal, great for both HiFi & Guitar Amps, many nice variants, a chameleon of Tones

SPECIAL HONORABLE MENTION IS THE 7355 TUBE* (RIP) - Small 6L6 variant, brilliant design, out of production (eg. Harman Kardon)

KT-77/EL34/6CA7 - Midrange Guitar "screamer", with a nice leading edge, crystal clear HiFi, very nuanced, KT77 smoothest

EL-84/6BQ5 - Musically engaging, great for Classical Music, a smooth operator, vocals are crisp and clean

7591/7591A/7868/6GM5 - Sweet sound, deceivingly smooth at high power, can kill speakers, current production is Russian

7027A (RIP) - Nice Warm & Detailed Sound, used when Tubes roamed the market

8417(RIP) - Audio Power Pentode, late bloomer, akin to a V8 and Oil Price Hikes, long out of production

6F6 Russian (US RIP) - In old Car Radios, absolutely fabulous tonality, a best kept DIY secret, listen here on 16 Ohm PSV-2


6V6/7408 - Lighter version of 6F6 but different sound, filaments are not as hungry as 6F6, can be bright, glassy-clear

6AQ5 (RIP) - Out of production, have a few on hand, will made a prototype amp, with plans to enjoy later

6CM6 - (RIP) also out of production, fantastic Jazz and Vocal, listen... a small 6V6, similar sound character, glassy-clear


E80L/6227 (RIP) - European 9 Pin Pentode. 10,000 hour PQ version, on my short list of Tubes to use, uncommon

2A3 - Single Ended Holography, Fine Bourbon & Single Malt Scotch, look for the Single Plate Sovtek

300B - The trusted voice of pure Class A - the golden S.E. standard - Expen$ive but Musical, used in Preamps as well

Special Mention Power Tube;

6146B - Commonly used for Radio Transmitters, used in Audio Amplifiers, bully of the block. Capable of 100W in PP

"Subjective" Small Signal Voltage & Gain Stage Tubes

Line Stages, Tone Controls, Phase Splitters & Buffers

ECC83/12AX7 - High-Mu, Dual Triode everyone knows something about, it is very common in Audio

ECC81/12AT7 - Medium-Mu Dual Triode, common in Guitar amps, seen less in HiFi amps (Fisher SA300)

ECC82/12AU7 - The true 9 Pin chameleon, Low-Mu, versatile, ubiquitous, handy, the toolbox of small signal tubes

12DW7/7247 - Half of a 12AX7 plus Half of a 12AU7cool tube (Dynaco S35, EICO 2036), nice tube

ECC88/6DJ8/6922 - Frame Grid design, a Love/Hate HiFi reputation, I love'em Hot and Bothered (Audible Illusions)

ECC85 - Used sparingly in Audio, very sweet, much more common in German Amps (Grundig)

EF86/6267 - A small Pentode Tube, everyone needs to listen to, most never have (Mullard 5-20)

6C4 - This is half of a 12AU7, small and petite, very cute, used in Hammond AO-28 Preamp (RIP)

6SN7/5962 - The bulldog of Small Signal Gain Stages, robust and musical (Cary Audio SLP-5)

6J5 - This just half of a 6SN7 (think 6C4), killer tone, a best kept secret, out of production (RIP)

6N7 - Rare metal audio tube, Stromberg Carlson Theater Amps (Stromberg Carlson APH50)

6SL7/5961 - Less seen in amps, Cary Audio used them in the 90's (SE300)

12BH7 - Robust dual triode, awesome & beefy, great good driver tube (Hammond AO-28)

ECC99 - The new kid on the block, speaks with an accent, nouveau 12BH7 (JJ Electronik)

6C45P - A best kept secret for Phono Stages, used in DIY for those in-the-know (Transcendent Sound)

6N1P - More robust than a ECC88/6DJ8, great driver for DHT Triode Tubes (ShermanAudio Kismet)

7199 - Out of production tube (RIP), Pentode/Triode, Russian version so-so (Dynaco ST70)

6AN8 - Out of production tube (RIP), Pentode/Triode (Dynaco MK3, some Japanese Amps)

Tube Rectifiers, the unsung heroes working in the engine room

"The unfair reputation" when it comes to music, Tube Rectifiers absolutely rule the tone department.

I hope to launch a Tube Rectifier revival.... QUIET, Shhhhhh, prices will skyrocket.

GZ34/5AR4 - 5V/2A Superman of tube rectifiers, general purpose (Dynaco ST70)

GZ37 - A somewhat filament hungry 5V/2.8A variant of the GZ34, British, rare & expensive

Type 80 Globe - Paleo Rare Tube Rectifier, too much for me as well, for museums

5Z3 - Also rare, museum stuff, not for DIY, unless there is extreme nostagia

5Y3/5Y3GT - Neutral 5V/2A, very reliable when operated within their maximum ratings, quick-on

6X4 - Lighter 6V/.6A version rectifier, mostly used in Preamps (Scott LC21)

5V4 - Rare now, 5V/2A sweetie, nice for medium powered amps 20 to 30w

12X4 - A 12V/0.6A version of a 6X4, same tube, different filament (Dynaco PAS)

6CA4/EZ81 - Like a 6X4, but not as popular, 1amp, think VOX (Leslie Reverb Cabinets)

5U4/5U4G - Robust Rectifier 5V/3A, tall, dark and handsome (US Navy)

5R4GY - That Sexy glass bottle, 5V/3A often seen with Brown Shorts (JAN)

5R4WGB - Potato Masher Rectifier, totally ready for Dinner and Battle (Military Grade)

6AX5/6X5GT - Popular 50's-60's 5V rectifier, similar to 5Y3 in ratings, 5V/0.6A from the 50's

274B - Western Electric, high end tube, available today, must be nice, Expensive as F, $$$

The Old and New Geek Testaments

Of  thy Sacred Electrical Theory

Remember always safety first

Prevent fatal electric shocks & Soldering Iron Burns

Always use Eye Protection

Never work when tired

Use good lighting and magnification

When measuring, one lead, always grounded

One hand with probe, other hand in pocket

No Alchohol when on the Bench

And don't spill the Coffee either


B.S.E.E. - Class of '86

BSEE Electrical Engineering 1986

Professional Engineer - P.E.

So far 36 Years of A/D Radio, Wireless Design & Digital Transmission

Vacuum Tubes are my #1 Hobby, #2 Guitar Playing, #3 T.B.D.

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