300b se schematic using a 76 driver tube

Morrison 300b singleended vacuum tube amplifier is shown below. The only thing to adjust are the anode load resistors in the 6sl7 and its cathode resistor as well since the bias voltage will change. If ever licensing for an improved version is available. The input stages consists of a preamplifier and cathode phase splitter using a ecc82 12au7, amplitude amplification driver using a ecc99 and cathode followers using a ecc82 12au7 tube. The reissue 300b by westrex sounded very close to the vintage we 300b. Good to see that we have finalised the tube 300b and using a choke input power supply. Aikido and 300b amplifiers once again i was overly pessimistic. The pada300bs frondend circuit utilizes nec and toshiba japanese. Tube amplifier project page after restoring a nice old 1938 sparton model 1568 console radio, i was so impressed with the quality of the sound that i started looking into building an amplifier using the same 2a3 output tubes that the big console uses. The amp uses two tubes in parallel, which makes it easy to produce 30 watts of clean and wonderful singleended 300b power. The el802 design performs a little better than the one above a 2stage driver using 704471195687, but suffers from lower gain and high input miller capacitance, so it is problematic to use with a. Above is the shunt regulated push pull driver stage with single ended 2a3 output. It is okay, but tends to sound a little mechanical and artificial. As a result my 300b is not sounding like a conventional 300b.

Loctal tube 7c57f7 single ended stereo amp 3 watts per channel 7f7 driver 7c5 outputs ss rectifier. This diy 300b triode amplifier project was completed by stamou tasos who is from greece. The output stage uses four 300b directly heated power triodes in a parallel pushpull configuration ia 40ma and vak 356 vdc with no negative feedback. Western electric model 91a clone we91a 300b stereo amp aka the dislocator 2x 300bs shuguan 300bz, 2x 310as nos cei holland, and 2x 6ax4 for 8 watts of set power in class a sophia electrics wecored 9103 opts, custom toroid power transformer, hammond choke. Given you already have a d3a about the best driver tube for a 300b amp i can think of in your amp, why not use it.

But my favorite usage of the 10y is in directly heated linestages. I have had such a success with jel 2a3 deluxe that i wanted to try the design with 300bs. For driver tube look for a low rp one, 2a3 would do. So if you choose the design carefully you can simply change the tubes. My hickok 600a cannot measure 300bs, but the cathode bias pot has plenty of adjustment above the 0. This is our diy tube amplifier with famous western electric 300b triodes and siemens c3g pentodes here strapped in triode mode. Raven audio spirit 300b reference stereo power amplifier. I could see from the 76 curves that the 76 would bias nicely using the 680 ohm dcr of the. The 300b is an unusual singleended tube amp with 300b power tubes. Diy 300b singleendedtriode set hifi amplifier project. Im using the 300b amp on the mediumhigh part of a klipsch heresy from 1973. He provides all the info anyone would ever need schematic, parts list, chasis layout drawings, and stepbystp instructions with photos. With most amplifiers, the reactive and delayed energy from the speaker driver greatly.

My guess was that the 300b would require too much voltage swing from the aikido stage. The 300b tube has the bayonet pin so located that it may also be mounted in a western electric 100m, 115b or similar socket. Driver circuitry will employ 6sl7 and 6sn7 in a differential direct coupled driver circuit. To my ears and those of my friends, these are as good as new production 300bs get but not as satisfying as the 845. The simple 45 started out as a basic two stage single ended 45 amp. These vacuum tubes employ medium, fourpin thrust type bases suitable for use in western electric 143b or similar sockets. Directcoupling eliminates final tubes being cut off due to the excess driving of the ac signal at the final tube grid, when driving final tube grids. Index introduction components simulation the main schematic power supply digital input stage sonic results layout views layout size my address. Furthermore, to drive 300b grids directly from the driver stage, a cathode follower cf is a good choice for the following reasons. A similar schematic uses the 6sl7 as a 2 stage driver, i might try it wired both ways. Using power tube as driver tube can give 300b a better driving power and incurs some of the characteristic of the driver tube into the amp. The simple 45 began as the starting point for a super tube amp design. Which means you can substitute the output tubes from 2a3, chinese 300b, cetron 300b, krone vv3252 family.

It is a parallel single ended, class a amp with zero feedback and. First and most notably, while the 300b triode output tube is usually seen in singleended amplifiers, designer s. The 300b tube works very well in traditional circuits and this is part of the reason why. A direct coupled driver stage and an all low mu triode array are the. You would need some 100 vrms to drive the 300b grids. The original tube amp schematic has a feedback loop, though the amp sounds very clear without it but i think there will be a place for a 3k. Sep 29, 2010 the input stages consists of a preamplifier and cathode phase splitter using a ecc82 12au7, amplitude amplification driver using a ecc99 and cathode followers using a ecc82 12au7 tube. Introduction this project born because some people ask me a little reference amplifier cheaper than the. The we91 with 6sj7 inputdriver and audio note 3k opts sounded very musical to my. Aikido octal mono pcbs and 5687 pcbs and aikido and 300b. So most amplifier designers just add another 6sn7 stage in front, using the second system in the envelope. The 5z3 is a nos national union that i got from antique electronic supply, as are the rca 6sn7s.

My amplifier is in for repairs and my tech would like to see the schematic. The simplest is using a driver tube and coupling cap and one of the simplest of these types is the je labs or angela design. I didnt include any individual tube bias or balance adjustments, so i am using matched pairs of 300b tubes. Shuguang 300b black treasures preamp and driver tubes measured strong. The greater efficiency and quality of the 755s showed that the classic jel 300b circuit could be improved. The pre amp and driver are made with 6sn7, best described as what goes in, is what comes out. I tried this inputdriver circuit with 76s and sonically prefer dc coupling between the. This special edition version has the vitamin q pio capacitors and the larger output transformers. The 10y makes an excellent driver tube for the 300b which will bring 300b amps to a complete new level in performance compared to more conventional driver tubes. Our 300b drd amp is derived from the classic loftenwhite design. The 300b tube works very well in traditional circuits and this is part of the reason why this ancient triode has become so famous worldwide. The regulated power supplies make this amplifier fairly easy to adapt for other tubes.

Eventually i acquired a pair of altec 755cs, a little later the altec 755as and mounted them on open baffles. I needed a simple single ended amplifier with excellent sound. Parallel pushpull 300b tube amplifiers diy audio projects. Many want to build a singleended, 300bbased amplifier that uses the aikido amplifier as the front end. The phase splitter feeds two separate srpp driver stages one for each output tube using 6cg76fq7 tubes. And the best product of that time was the 300b set amp se1. A quartet of 6550kt88 are used per channel in ul connection with cathode feedback.

I have also succesfully used the 10y as a driver for the 45. With an input tube of mu around 20, and a 2a3 driver tube with 1. The tubes may be mounted in either a vertical or horizontal position. Time bandit 300b single ended triode amplifier 9 watts per channel 6sn7 drivers 300b outputs 83 mercury vapor rectifier. Stereo integrated push pull 300b aquablue diyparadiso tube. Parallel pushpull 300b mono amplifiers rudolf moers from the netherlands has kindly sent us details of his parallel pushpull 300b monoblock tube amplifiers to share with the diy audio community. The three best sounding designs are presented on the this page. An sv300b pushpull amplifier plitron manufacturing. The preamp and driver circuit of this amplifier is a classical one.

I built a pair of mono blocks using the same driver stage 18 years ago. Amplifiers on steroids, designed for maximum output power, dont have the softness of a single ended triode. The unnecessarily complex 300b amp having never built a singleended 300b amp, i figured the right thing to do would be to go overboard. Oct 16, 2010 using power tube as driver tube can give 300b a better driving power and incurs some of the characteristic of the driver tube into the amp. Get the owners manual for the manley compact sepp 300b monoblock pdf. These choices will certainly help in meeting our key deliverables. The complete driver board can deliver over 150 volts pp from 10 hz to 50 khz. I have a pp 2a3 that i am running at lower voltages also, for the same reason. It should be quite obvious from the photographs that the design and construction of a pair of amplifiers this size is by no means a small undertaking. Using audio output transformers with a primary impedance of about 3000 to 3500 ohms you can expect about 8w of output with at about 2. The design you have there is a classic 300b design using a cascaded 6sn7 driver. This 300b singleendedtriode set amplifier circuit uses a direct coupled 6sn7 driver stage.

Its a nice sounding amplifier, but the 6sn7 is nowhere near the ideal driver for a 300b. In this project the budget will be not considered so it will use only the. The end stage is designed with a vintage working point of the 300b. We heard slightly more volume from the reissue 300bs, but that may be because my old 300bs are a little tuckered out from many years of use. My first one was about 10 years ago, thoroughly tweaked out, sold to me by a nice fellow from slovenia. Tube voltage regulation, and fixed bias will be employed. I am using the sophia branded tj perforated plate 300bs. The input tube was a 12at7 ei yugoslav tube and the driver was the beefy 7044 or. I have done temporary adaptations to try both 45s and 50s. The legendary 300b power triode has long been the first choice of many serious music listeners because of the natural, emotional presentation of amplifiers using this power tube. Grid bias for the 300b tubes is generated by a shuntregulated bias supply pcb that i designed.

Using a tube rectifier and choke filtered power supply it gives true musicality especially when connected to horn and single driver full range speakers. The only thing to adjust are the anode load resistors in the 6sl7 and its. My choice was to build a very simple circuit, but using the best components i. I also built the 6sn7300b of je labs but i prefer the 766sn7300 better. When i first began building single ended triode amplifiers the vacuum tubes of choice were the 300b, the 2a3, and the 45. The el802 design performs a little better than the one above a 2stage driver using 704471195687, but suffers from lower gain and high input miller capacitance, so it is problematic. The design employs type 76 direct coupled to 12 section of a 6sn7 driver capacitor coupled to the grid of the output tube. Cf offers lowoutput impedance a few hundred ohms or less. I started with a singlestage driver using a triodeconnected el802 you could also use the plentiful pl802 but would need a separate filament transformer. Derek waltons diy 300b set amp mk1 is one of the most popular and respected freely available designs on the web. It provides excellent performance using nonboutique, affordable parts.

Tube power amp schematic of triode preamplifier with 37 and 76 pre wartubes the american prewartypes 37 and 76 have the same heater 6,3v 0,3a and quite similar platecharacteristics. Operation with and without loop feedback will be possible. The self bias design and optional hum pot included enables 300b tube rolling to be an easy task for everyone. Han has opted for pushpull design, with two 300bs per channel and a reported output power of 28wpc according to the owners manual or 36wpc according to the raven audio website.

Secondly i use two driver tubes per channel so that only half is used. The most prized of these tubes put out only a watt or two and sound spectacularly musical through a high efficiency speaker. New tango 2008 fe12s with 2a3c single ended amplifierdrive by ecc83 afg srpp into 2a3, i like sound of sovtek 2a3 mono plate valuvethan new type such as 2a3eh and 2a3c. I tried a we4175842 2stage design, cap and dc coupled, 3stage with either a 76 37 or 6j5 or 12 6sn7 on the first stage and the second stage with a higher gm tube 5687, 6bx7, 6bl7 and etc. Driver stage is differential using 12ax7a and 12bh7. Using a 300b or sovtek 6a3 tube the output will be over 10 watts, 1db 18 hz to over 20 khz, less than 1% distortion and only needing 0. Its been around for donkeys years in various guises ala je labs, walton audio, sun audio etc. With the asiandriven passion and resultant revival of single ended topology the. The input stage also relies on two paralleled triodes ecc88, which drive the 300bs through a. It had good power, able to drive my klipsch and tannoy lancaster to thundering levels.