300b se schematic using a 76 driver tube

I built a pair of mono blocks using the same driver stage 18 years ago. Parallel pushpull 300b tube amplifiers diy audio projects. Conventional hybrid power amplifiers are constructed using vacuum tubes in the. The pada300bs frondend circuit utilizes nec and toshiba japanese. The simple 45 began as the starting point for a super tube amp design. Our 300b drd amp is derived from the classic loftenwhite design. The input tube was a 12at7 ei yugoslav tube and the driver was the beefy 7044 or. It provides excellent performance using nonboutique, affordable parts. I didnt include any individual tube bias or balance adjustments, so i am using matched pairs of 300b tubes. This is our diy tube amplifier with famous western electric 300b triodes and siemens c3g pentodes here strapped in triode mode. 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. I could see from the 76 curves that the 76 would bias nicely using the 680 ohm dcr of the. Shuguang 300b black treasures preamp and driver tubes measured strong.

I have also succesfully used the 10y as a driver for the 45. The tubes may be mounted in either a vertical or horizontal position. 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. Index introduction components simulation the main schematic power supply digital input stage sonic results layout views layout size my address. My hickok 600a cannot measure 300bs, but the cathode bias pot has plenty of adjustment above the 0. 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. An sv300b pushpull amplifier plitron manufacturing. Grid bias for the 300b tubes is generated by a shuntregulated bias supply pcb that i designed. Get the owners manual for the manley compact sepp 300b monoblock pdf. 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. 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. This special edition version has the vitamin q pio capacitors and the larger output transformers. It is okay, but tends to sound a little mechanical and artificial. 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.

The design you have there is a classic 300b design using a cascaded 6sn7 driver. The midrange in the reissue tube, which has always been what singleended triode amps using. Secondly i use two driver tubes per channel so that only half is used. I have a pp 2a3 that i am running at lower voltages also, for the same reason. It had good power, able to drive my klipsch and tannoy lancaster to thundering levels. Aikido and 300b amplifiers once again i was overly pessimistic. Introduction this project born because some people ask me a little reference amplifier cheaper than the. My amplifier is in for repairs and my tech would like to see the schematic.

My guess was that the 300b would require too much voltage swing from the aikido stage. When i first began building single ended triode amplifiers the vacuum tubes of choice were the 300b, the 2a3, and the 45. The input stage also relies on two paralleled triodes ecc88, which drive the 300bs through a stepup transformer. As a result my 300b is not sounding like a conventional 300b. The simple 45 started out as a basic two stage single ended 45 amp. Raven audio spirit 300b reference stereo power amplifier. The input stage also relies on two paralleled triodes ecc88, which drive the 300bs through a. It is a parallel single ended, class a amp with zero feedback and. My first one was about 10 years ago, thoroughly tweaked out, sold to me by a nice fellow from slovenia.

Loctal tube 7c57f7 single ended stereo amp 3 watts per channel 7f7 driver 7c5 outputs ss rectifier. Tube amplifiers, schematics, parts, triode amplifiers. A direct coupled driver stage and an all low mu triode array are the. 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. The most prized of these tubes put out only a watt or two and sound spectacularly musical through a high efficiency speaker. The only thing to adjust are the anode load resistors in the 6sl7 and its. With the asiandriven passion and resultant revival of single ended topology the.

But my favorite usage of the 10y is in directly heated linestages. My choice was to build a very simple circuit, but using the best components i. To my ears and those of my friends, these are as good as new production 300bs get but not as satisfying as the 845. My next amplifier project will utilize a pair of 300b per channel in pushpull configuration for about 40wrms per channel output. If ever licensing for an improved version is available. 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. Cf offers lowoutput impedance a few hundred ohms or less. Eventually i acquired a pair of altec 755cs, a little later the altec 755as and mounted them on open baffles. The unnecessarily complex 300b amp having never built a singleended 300b amp, i figured the right thing to do would be to go overboard. And the best product of that time was the 300b set amp se1. I have heard, my preference for driver or output is good to better 300b, 2a3, 45, 5071a845. This diy 300b triode amplifier project was completed by stamou tasos who is from greece. Which means you can substitute the output tubes from 2a3, chinese 300b, cetron 300b, krone vv3252 family.

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. Driver stage is differential using 12ax7a and 12bh7. 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 300b tube has the bayonet pin so located that it may also be mounted in a western electric 100m, 115b or similar socket. The regulated power supplies make this amplifier fairly easy to adapt for other tubes. I tried this inputdriver circuit with 76s and sonically prefer dc coupling between the.

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 self bias design and optional hum pot included enables 300b tube rolling to be an easy task for everyone. 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. With an input tube of mu around 20, and a 2a3 driver tube with 1. 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. A quartet of 6550kt88 are used per channel in ul connection with cathode feedback. I have had such a success with jel 2a3 deluxe that i wanted to try the design with 300bs. I have done temporary adaptations to try both 45s and 50s. The end stage is designed with a vintage working point of the 300b. Good to see that we have finalised the tube 300b and using a choke input power supply. I also built the 6sn7300b of je labs but i prefer the 766sn7300 better.

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. 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. Its a nice sounding amplifier, but the 6sn7 is nowhere near the ideal driver for a 300b. First and most notably, while the 300b triode output tube is usually seen in singleended amplifiers, designer s. You would need some 100 vrms to drive the 300b grids. The complete driver board can deliver over 150 volts pp from 10 hz to 50 khz. Diy 300b singleendedtriode set hifi amplifier project. So most amplifier designers just add another 6sn7 stage in front, using the second system in the envelope. Its been around for donkeys years in various guises ala je labs, walton audio, sun audio etc. Tube voltage regulation, and fixed bias will be employed. 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.

Im using the 300b amp on the mediumhigh part of a klipsch heresy from 1973. Here is a longer dissertation of the amplifier theory that i wrote up. Morrison 300b singleended vacuum tube amplifier is shown below. 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. For driver tube look for a low rp one, 2a3 would do.

The preamp and driver circuit of this amplifier is a classical one. Where i parted company with the sedht crowd was singleended circuits. 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. Aikido octal mono pcbs and 5687 pcbs and aikido and 300b.

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. If used as a rc coupled driver for a 300b in a zero feedback single ended amp which is a very common use of the 6sn7 these days its gain is not enough to stick with just a single driver stage. 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. Amplifiers on steroids, designed for maximum output power, dont have the softness of a single ended triode. The greater efficiency and quality of the 755s showed that the classic jel 300b circuit could be improved. I am using the sophia branded tj perforated plate 300bs. I needed a simple single ended amplifier with excellent sound. 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. The 300b tube works very well in traditional circuits and this is part of the reason why. These vacuum tubes employ medium, fourpin thrust type bases suitable for use in western electric 143b or similar sockets.

The 300b is an unusual singleended tube amp with 300b power tubes. May 02, 2014 first and most notably, while the 300b triode output tube is usually seen in singleended amplifiers, designer s. With most amplifiers, the reactive and delayed energy from the speaker driver greatly. In this project the budget will be not considered so it will use only the. The 5z3 is a nos national union that i got from antique electronic supply, as are the rca 6sn7s. Above is the shunt regulated push pull driver stage with single ended 2a3 output. A similar schematic uses the 6sl7 as a 2 stage driver, i might try it wired both ways. So if you choose the design carefully you can simply change the tubes. 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. 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. 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. Derek waltons diy 300b set amp mk1 is one of the most popular and respected freely available designs on the web. Time bandit 300b single ended triode amplifier 9 watts per channel 6sn7 drivers 300b outputs 83 mercury vapor rectifier.

I started with a singlestage driver using a triodeconnected el802 you could also use the plentiful pl802 but would need a separate filament transformer. Stereo integrated push pull 300b aquablue diyparadiso tube. The we91 with 6sj7 inputdriver and audio note 3k opts sounded very musical to my. Operation with and without loop feedback will be possible. Driver circuitry will employ 6sl7 and 6sn7 in a differential direct coupled driver circuit. The reissue 300b by westrex sounded very close to the vintage we 300b. The three best sounding designs are presented on the this page.