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Developing audio in Ireland
by Derek Walton

Worldwide 300B Builders

See how the other half lives...



Just some of the 300B amps that some correspondents have made....I always think it is nice to see just what others have done to the same project and how they tackled it. A source of inspiration for you, I hope. If there are any other builders out there who have made this, I would like to see photos of it, in order to include them on this page.

These are only the people that have sent me photos but what is a common thread is that a lot are first time builders of tube gear and despite their lack of knowledge/understanding, this project just goes to show that it is possible for just about anyone to make this amplifier. So all you self-doubters out there....wake up and smell the solder. You can do it!!!

Click for larger image

Roberto MariniRoberto Marini - Italy

Jun '07 - Using Hasimoto transformers, Roberto's first valve project with seperate PSU makes this one very neat little amplifier!

His construction page of these amplifiers is HERE

Roberto Marini

RCA red base 5692, Audionote coupling cap and Blackgate are just some of the fine components he uses. Destined to be used with vintage Goodmans on open baffles.

Marco Marco and Angelo - Italy

Jun '07 - Marco had custom made transformers made by Novarria, Milan for this really neat integrated version that uses solid state rectification for compactness. Once again the Italian stlye come through with a carbon fibre chassis top. Looks super with this finish and I expect that the carbon fibre with its good acoustic properties will result in a fine sounding amplifier.

Marco

" ... using RCF Mito speaker and the sound is great! - Much better than other amplifiers such as KT88 and EL34 used with this speaker. "

Albert Ching Li Albert Ching Li - Vancover, Canada

Jan '07 - Albert is at it again .... yet another creation from Albert .. must be those cold winter days in Canada that gets you going! As he says .... " and I've just finished my 300B mk3 a few days ago. It is one of the best amp I build so far. "

Albert Ching Li Albert Ching Li - Vancover, Canada

- Albert is using the EML300BXLS and CV-6 as the input and driver tubes, together with GZ37 rectifier and Double C core opt with OFC wire. Custom EI ptx and choke.

TaegeunPark Taegeun Park - South Korea

Jan '07 - Tae wanted to build his life long dream system, he had some reservations initially since this was his first DIY project, but he has now gone though a "tunnel of joy - truely a joy and thrill. It is wonderful and extraordinary. I still can't forget the time when I first pluged and powered them up. I named 300B amp "The Taste of Honey"-which is definitely true...".

TaegeunPark Tae really shows us just what can be done when there is a will and a desire to do something that you have wished for and never thought was quite possible. Using Western Electric 300B and GZ37 rectifiers it is now partnered with vintage Goodmans 201 and Fostex FT17H in open baffles with hinged adjustable wings. This is exactly the same system that I have had and knowjust how wonderful this combination sounds. Well done Tae!!
TylerTyler - St. Paul MN USA

Dec '06 - Using the Angela power transformer makes this amp switchable to use either a 300b or 2A3 tube. Made even easier now that Tyler is using 2.5v 300b, also switchable heater supplies allow the use of 27,56 76 in place of the 6sn7. Driver tube is a 6J5. The vacant octal socket is used when fitted with 6sn7. Nice idea that you can use 2A3 or 300b and either a single 6sn7 or any of the single triodes instead... every angle seems to have been covered here!

The primary reason for building this amp was to actually listen to the tubes of the various types just described so I could build something that takes the best of these options next.The speakers are Celestion series 5, in this room are only 88db but upstairs in my listening room I've got Lowthers running on a Transcendent Sound SET/OTL. That's an amazing amp in terms of accuracy and transparency and its DEAD quiet even immediately in front of the 104db lowthers, but I'm really loving the old DHT SET sound so who knows how long it will last.

Danny Gullick Danny Gullick - Memphis

Dec '06 - Danny now upgraded the Hammond 1627 for the Hashimoto H-20-3.5U. A double C-Core design with a 2.5k and 3.5k primary.I originally used the 2.5k primary connections in order to compare with the Hammond 1627s that were replaced. The highs and mids sounded ok and the bass was lacking something. Over time, the bass improved, but the mids seemed muddled.

Switching to 3.5k, made all of the difference. The mids smooth and well defined, the highs were just liquid and the bass was well defined and solid. The Hammonds had a little more authoritative bass than the Hashimotos. But the Hashimotos win hands down in all other departments.Switching to TJ Mesh Plate tubes, changing to DC filaments, removing the pots and adding on/off lights. The TJ and the Hashimotos is a match made in haven J. The music just seems to float in front of you. I would say this combination has excellent detail and are not harsh. Used with Altec Valencia 846B speakers. Visit his web site HERE

Scott Gerus Scott Gerus - Milwaukee USA

Dec '06 - Stunning woodwork here from Scott - "Im just amazed how good this thing sounds. I build this amp for the challenge and something to do over the winter. The fact that you can actually hear the difference is just a BONUS"

Scott Gerus Scott Gerus - Milwaukee USA

Dec '06 - Scott is now on the way to his second version as an integrated, with improved PSU and MagnaQuest output transformers. "I ended up with the 5691 in parallel, loaded with a 4.2mA ccs source, capacitor coupled to the 300b. Learned a lot about ground loops and HUM. Ended up with DC on the 300b heaters to get down to .2mV HUM"

Rutcho Suvandjiev Rutcho Suvandjiev - Bulgaria

Dec '06 - Rutcho is one of the founders of Bulgarian Audiophile Society and shares this beautiful one with us here.

This amplifier uses a JJ 300B in a cathode bias circuit, bypassed with Black Gate. The input/driver tube is General Electrics 6SN7 GTE, cathode resistor bypassed with Solen PPE capacitor. The interstage capacitor is Jensen Paper/Oil/Cooper Foil. The chassis is 4mm solid cooper, mounted on a white cherry frame, standing on SoundCare spike legs. The rectifier is russian black anode 5U4G filtered by pi-filter using custom-made four-section drossel and JJ capacitorss. The output transformer is Hashimoto 20-3.5U. The amplifiers are attached to the slightly modified "Jericho" backloaded horns using Fostex FE-208 Sigma drivers.

Louis Croteau Louis Croteau - Montreal - Canada

Jul '06 - All tubes are Electro Harmonix, output transformers are James 2k5

"The amplifier sounds wunderfull My wife and I, opened a bottle of wine to celebrate ! I really think this one of the best sounding tube design and DIY project you can built."

Ken Au Ken Au - Vancouver, Canada

Jun '06 - This cool looking integrated Mk.II 300b with copper top plate, uses James 6123HS OPT, Hammond 378X PT, Military Chicago 8H 250 mA choke, Electro Harmonic 300B-gold grid and RTT -6SN7. Jansen Copper foil coupling cap and Riken resistors. The PSU and amp are in separate compartments - a neat idea and makes the whole amp extremely compact looking. Blackgates and motor run oil cap in the PSU. A lovely implemtation of the project I think!

"The sound is stunning and exceeded my expectation. The power is more than sufficient."

Walter Lo Walter Lo - Canada

May '06 - This 300b is the Delux version with improved PSU using dual chokes and BlackGate caps with Chicago military power transformer. However, the usual 6sn7 is replaced with a UK made CV6/DET20/VT135, and is prefered over the more conventional 76 and 6J5/L63 or 7193 options. The DET20 is a Dull Emitter Transmitting valve, the VT135 is the miltitary version and later classsified as CV6. As Walter says -"It is an amazing valve. Simply stunning. Give it a try!!" Once again, another breaking away from the pack and using seperate input and driver valve. Output Transformer is by Plitron, and as Walter says - "it is simply fantastic"

Vincenzo Cuttitta Vincenzo Cuttitta - Palermo, Sicily - Italy

May '06 - The "Arpeggione" Triode Amplifier ... Lets call this the Mk1.5 since there is some variation from the Mk1, but very similar. Vincenzo's workmanship has to be seen to be believed, which I did on a recent visit to his home. Master craftsmanship at its best. This has got to be THE nicest implemtation I have seen - attention to detail is neurotic! A Marconi 6J5G and a Sylvania 6J5GT round plate on the front end replace the usual 6sn7, with superior results and the rectifier is a 5U4G type and finally the Svetlana 300B. The power transformer is custom made by Novarria in Italy and what a job he does! Output Tx and chokes from Hammond. All the caps are custom made ASC BlueLine and these are also used on the cathode bypass of the driver and the 300b. Not an electrolytic in sight! All natural cotton covered internal wiring and 2mm fine silver 99.99% ground buss.

It's the best amp I ever heard!! Wonderful sound!! I STILL NOT CAPACITATE THAT I HAVE BUILT THIS WONDERFUL INSTRUMENT OF MUSIC!! .....NIRVANA with the 1.5!!! It's unbeliveable, it has something... MAGIC!!! TRUE music! like dal vivo!!!

Vincenzo Cuttitta

Vincenzo's site and full detailed construction is here ...HERE. ...This is a "MUST SEE" article, as is all of his other super projects, a true example and inspiration to all of us of the care and attention in every aspect of this hobby - ENJOY!!!.

Massimiliano Candeloro - Rome, Italy

Apr '06 -Very nice chassis that uses two 6J5 valves here in place of the usual 6sn7 after a recommendation from Vincenzo ( above), a Marconi 6J5, RCA 6j5GT. Rectification is by Svetlana 5U4G and finally the Electro Harmonix 300B gold plate. ASC oil caps throughout, including as bypass... no electrolytics. How it sound?... "Very fine, wonderful, marvellous, it exceeds my expectation. ....!!!!"

Nicolas Prontonotarios Nicolas Prontonotarios - Rio De Janeiro, Brazil.

Jan '06 - Nico's first tube amp project and what a way to start! This is an integrated version of the Mk3 and is built as an integrated dual monoblock, but within one 10mm aliminium hand made chassis. QUITE a feat to fit everything into the small a space I can tell you! Nico is using here the EML520, but since upgraded to the KR842VHD. Plitron OTX, Amplimo PTXs, Hammond chokes and ASC oil caps. Nico is using this with Zingali Overture speakers.

Scott Gerus Scott Gerus - Milwaukee USA

Jan '06 - Stunning woodwork here from Scott - "Im just amazed how good this thing sounds. I build this amp for the challenge and something to do over the winter. The fact that you can actually hear the difference is just a BONUS"

Albert Ching Li Albert Ching Li - Vancover, Canada

Jan '06 - Alberts Integrated ...The new amp with James 6123HS opt and GZ37 ( CV378 ), Tungsol VT76, Sylvania 6J5GT, and of course the Emission Lab 300Bxls. All resistors are Riken and with Blackgate cap by-pass. This is under testing and tweaking, but one thing for sure this James opt is lot better than the Hammonds!

Albert Ching Li Albert Ching Li - Vancover, Canada

Mar '04 - Albert is using Hammond and Angela ironware, with TJ tubes and 5u4 in this, his first version of the amplifier.... I like the gold finish! Made as left and right handed pair. He uses them with Wharfedale 12" fullranger on a Open Baffle

Rahal Patrice Rahal - France

Nov '05 - Alumimium chassis with original WE transformers and WE cable, together with Allen Bradley resistors. 91b western electric, schematic used original tube 310A /300B/274A Driving Focal +"15" audion 15A , driver TAD-4002+ horn wood TH-4002. tweeter ESS /AMT. One classic sweet set-up there!

Reifenberger Michael Reifenberger - Germany

Oct '05 - And still they keep om coming! ... The housing is built using CNC cut 3mm brushed stainless steel and are driving a pair of Hedlund-Horns, with Lowther EX4 drivers. An excellent combination Michael says. Using GZ37 and DC on the heaters Nice one !!

Reifenberger Michael Reifenberger - Germany

Oct '05 Michaels amps with the gorgous Hedlund-Horns, with Lowther EX4 drivers.

Noble Noble Dallison - Arkansas

Oct '05 - Another! ... Oct '05 - Another! ... "using a pair of Klipsch Heresy; direct to cd and they sound very rich and dark in his small office. The cd sound goes away. I beleive that they are the biggest bang for the buck possble. "

Sergey Sergey Didkovsky - Ukraine

Oct '05 - Nicely appointed with Sowter SE07S output TX, Sowter custom made power TX and Sowter CA15 choke - with every component fitted to the top plate of the chassis and are happily driving AudioNote AN-J/L speakers. Russian Military 1578 (6sn7) and Svetlana 300b and 5U4.

SergeyI have decided to try WE91 schematics, on a pentode 310A. I used not original WE310A, and its analogue 10Z12S (manufactures "Svetlana"). A sound 310A it is simple the best. Is more interesting, than 6SN7. I think, this very successful combination 310A+300B!
Daniele Daniele Manfroni - Italy

Integrated version with Hammond iron. Colourful one from Italy.

Paolo Paolo Manestap - Italy

Jan '05 - An Italian student with the passion of hi-end. Now it's playing...very very well...It meets all my expectations, sincerly I didn't think that it could play so good...

Dave Stanard David Stanard - Houston, USA

Jan '06 - David, now emerges with is second version, but this time he is using the EML300bXLS and has cleaned things up a little. Top panel is etched and anodised and the input tube is now the RCA 5692, everything else is as the one above.

Dave has now gone on to form his own cable and power conditioner company - chech it out - Silver Circle Audio

Dave Stanard David Stanard - Houston, USA

Jul '04 - David, who is a master craftsman in cabinetmaking, has made his base from Cherry timber with polished 4mm aluminium chassis top panel and using Angela and Hammond ironware, Angela Caps, Riken resistors, Valve Art 300B, Mullard GZ37 and RCA or GE6sn7gtb. David never made anything before, so here is testement that even a person with absolutely no knowledge can do it. A man of perseverence - I feel as if I was there throughtout the whole process.

Dave Stanard David Stanard - Houston, USA

Jul '04 - Here they are sitting on top of a pair of now redundant Marsh monoblocks driving the fabulous Soliquoy 6.5 speakers and Silver Circle cables throughout. I got a phone call from him the first day he fired them up - "Man - they are too loud. They have an ambience and presence that the Marsh just dont do "! Or as he says "Bordering on the Mystical!" - and all in a room 30ft long with 15 ft ceilings and the listening position 14ft away. We are talking *big* space. Not bad eh? Ha - whats that about *only* 8 watts?!?!?! Now looks like maybe the $10,000 Marshes will have to find a new home. Now he is about to make another pair....Congrats Dave - your certificate is on the way!

Jerry Curtis Jerry Curtis - Michigan, USA

Jul '03 - Really beautiful example of fine workmanship here using a red oak base. Electro Harmonix 300bs and 5U4. Mods included placing a high quality, low value capacitor (.1uf Sprague orange drop) in parallel with some of the electrolytic capacitors in the circuit. I am also adding a switch between ground and my high voltage center tap. I am really enjoying the sound, and I can say that this is my first DIY amp and definitely not my last.

His audio journey is -HERE.

Arnold Cruz Arnold Cruz - Philipines

Apr '03 - Looks stunning in this color I think...well, it just look right! What about more like this ?

Its the DX version and use RCA 76, Hitachi 6SN7WGTB, RCA 5U4G and generic Chinese 300B. The transformers are all custom wound with the exception of the Hammond 193J choke, carbon film resistors and Black Gate bypass capacitors. Sprague ATOM and Nichicon MUSE for the power supply capacitors were used.

His audio journey is -HERE.

Thomas Schick Thomas Schick - Berlin.

Cant tell you a lot about this, except that you can visit his web site HERE. Interesting the way the top is split into four sections to enable possible changes in the future - nice idea.

Francisco Lopez Francisco Lopez - Spain

OK, Espania this time - and uses a complete copper box, Electro Harmonix 300B, General Electric 6sn7 and National 5U4G with Cardas internal cable. and to quote him - *Now I enjoy a sound never before listened to by my ears* ...well thats good enough for me!

Paul Austin Paul Austin - California

Nov '02 - Superb woodwork on this walnut and tulipwood chassis, topped with copperdeck and facia with bias meter - Electraprint audio transformers. Yamamoto's teflon sockets with Svetlana 300b, RCA 5692, NU 76, Mullard GZ37. "Sounds wonderfull!"

Ed Billeci Ed Billeci - USA

Sansui 1000 opt trans, with the lams re-stacked and gapped for S.E. use. Bandwidth is 40khz, with 1db of feedback. Input stage is SRPP 6SL7. Power supply is 5V4 and all polypropelene capacitors. Coupling caps are Hovland, all internal wiring is pure silver solid core. Alps "Black Beauty" volume control.

Danny Danny Gullick - Memphis

Dec '02 - The chassis is from Welbourne and the finish looks great. Danny's first attempt at tube DIY - yes, another first timer who completed it with no problems, just in time for Christmas 2002. Angela power and Hammond 1627, Valve Art nickel plate 300Bs and Sylvania 6SN7GTB. As he says - I am simply amazed with these amps.. While trying to type on my computer.. a song will come on and I just have to stop and listen.... Visit his web site HEREfor a step by step construction.

Somjade Jay Songcharoen Somjade Jay Songcharoen - Mississippi, USA

Who says SETs cant rock? Just look at Jay's set-up here with Dj decks and Klipsch Reference RB5 - the 300Bs are on the floor under the decks. Jay's a first time DIYer and proves time and time again that this is an almost fail-safe project. Angela Ironware and 5692 input tubes. Chech out his site Jaded Beats HERE - hey, great name there Somjade!

Bill Ellis Bill Ellis - Calafornia

Bill is using Hammond ironware, Sovtec 6sn7 and JJ's - with 5692 on their way. Very nice with the rounded corners and feet too. He says it best..."and Ill be dammed I would not believe 8 watts of triode power would sound so rich and full if I had not heard it with my own ears." Its the same old story over again!!!!

Sergey Didkovsky Sergey Didkovsky - Kiev, Ukraine

As one might expect - Russian tubes here! Driver: 1578(6N8S), Russian military version of 6SN7, NOS 1980, metal base, perforated plate. Output - 300B Svetlana, Rectifier - 5C3S Svetlana, Russian version of 5U4, NOS 1963, Yes, that is only the top panel - the base has yet to be completed.

Martin Bunjes Martin Bunjes - Amsterdam

Martins beautifully executed creation in powder coated satin black The OPT is a amorphecore type, made in Holland and which gives incredible bass and definition.... Contact him at here

Martin Adams Martin Adams - England

Having seem every detail of Martins build I can say that what he has produced is a truly stunning precision built and hand polished amp with 5mm aluminimum . Martin chose to use the same method of construction as yours truly., Sowter ironware throughout, tantalum R's for the signal path and Riken Ohm for all the rest, RCA red base 5692, JJ 300B and RCA 5R4GY rectifier tubes. And a hum balance pot for the 5692 heater supply. Speaker that he has the option of using are Lowthers or Ruark Talisman

Mikess 300b frontMike Jedrejewski - Maryland,USA

What can I say? Absolutely beautifully finished and fitted with Hammond ironware and GE 5U4Gb, JJs and RCA 6SN7. Mike is a first time builder of tube equipment and ...yes..it worked perfectly first time with no problems. But not quite enough power to drive his Wilson Watt Puppies in his 23 x 28 room.... so off he went a huntin' and found Klipsch Heresey's - that should do the job!

Evanelos 300B Evangelos - Athens

Power transformers were ordered from Sowter, output transformers are Audio Note 3K/140mA, input tubes are GE 6SN7GTB (I have also tried RCA, Sylvania and Philips), rectifier tubes are Mullard CV378/GZ37, output tubes are JJ Tesla (I just put them a month ago, on the pictures you see the previous used of the Svetlana brand), coupling capacitors are Jensen copper foil/paper in oil, bypass capacitors are ELNA Cerafine, resistors are Holco.

JFL 300b frontJean-Francois Lessard - Quebec,Canada

He's the man! This lovely integrated version from Jeff uses Magnaquest OTX and JJs with 5692 input tubes. Jeff has been unbelievably helpful to me over my period of construction and is a mine of information. I may not have had the confidence to do it myself unless I was safe in the knowledge that if things went wrong that Jeff would be there. This is the man behind Pantheon Audio, the Seth and much more - catch up with Jean-Francois HERE

JFL 300b backMaking it on a single chassis just goes to show just how neat it can be if you like this rather than the mono-block build
James 300b front James Yeung - Toronto,Canada

Another newbie to tube construction here. You can check out his construction notes on his site here . This version has been heavily modified especially in the PSU side, he says and despite wiring up the grid and plate of the 300b in reverse and blowing the fuse - no problems resulted to the tube! The TXs here are enclosed with MDF boxes.

JEL System Joseph Esmilla -

The housing is built using 3mm brushed stainless steel and are driving a pair of Hedlund-Horns. JE300B and Hedlunds are an excellent combination btw. Thanks for your effords on the 300B front btw!

Visit his web site * HERE *