For the audio output transformers (T1) I used Lundahl LL1623 Transformers (90mA) - PDF (52kB). In an email exchange with Gio he recommended that I try the LT1085 voltage regulator circuit shown in Figure 2 for the 300B filaments. The transformers and choke are all from Hammond. This DIY 300B triode amplifier project was completed by Stamou Tasos who is from Greece. Both of my 845 amps have wonderful tonal balance, articulate … INTRODUCTION This new reference design born like an upgrade of my 4300B SE and It is the best choice to drive hi-end full range loudspeakers with high efficiency like Lowther, Fostex and Fullrange-Speakers. With all of the many tube and speaker combinations that we tried, every time we found that we both preferred the sound quality from my DIY 300B SET amplifier over that of the Sofia Electric SET 300B. Ultralinear circuit uses an extra set of windings in the output transformers. V2 is 6CG7/6FQ7 for normal use. The long shafts on the left and right edges of Photograph 2 are from the 300B hum potentiometers (P2). The most exciting feature of this amplifier kit is that not only can the famous 300B output tube be used, many other common power tubes are options as well. This amp is the quintessential triode amp. For those within the SET brigade there are deep individual preferences for different tubes: 45, 2A3, 300B, PX25, 211, 845 and so on. This realization quickly spread to Europe and then the whole world with this type of amplifier being regarded as an all time classic. As a thank you for the 300B amplifier schematics, Stamou has shared with us his implementation of the 300B single-ended (SE) tube amplifier schematic by J.C. Morrison. Review by Noam Bronstein. Over-sized stereo chassis (20" wide by 12" deep) allows space between components, as well as, use of oversized flagship 300B output transformers that is made to our specification, it is capable of a staggering 30 watt output. This gives the smoothness of SET amps with the power and dynamics of push/pull design. We made a direct comparison against the Sofia Electric SET 300B equipped with JJ 300B triode tubes. The single-ended 300B tube amplifier circuit will deliver about 8 Watts and is well suited for use with high sensitivity speak… 300B Single-Ended Triode (SET) Amplifier Schematic. Some time ago I’ve got a set of custom-made power transformers by JMS Transformers in the UK. Here is a little update to this SE 300B triode amplifier project. A Two Chassis Single Ended Fixed Bias 300B Amplifier With Fully Regulated Supplies. The output stage is a SE 300B triode and the maximum power output is about 8 Watts per channel. Keep this in mind as you are making up a parts order list for this 300B SET amplifier project. Stephen (sampleaccurate on the forum) put together a 300B SET amplifier following the above direct-coupled 6SN7 driver / 300B SE amplifier schematic. Remember that the maximum anode voltage for the 300B triode tube is 450V. What were those design priorities? As music pours out of Elekit’s new amp through my speakers, I’m smiling, and remembering that some things are much more than the sum of their parts. For your reference, the tube pinout diagrams for the the 6SN7 twin triode, 300B directly heated triode and 5U4GB twin diode tubes are shown in Figures 3, 4 and 5. Created 24 March 2014. I did not deviate all that much from the original SE 300B schematic that I was following. In my experience, a high quality audio output transformer is required for superior performance with SE tube amplifier circuits. The power transformer (T2) is shared between both audio channels of the SET amplifier. The tubes used most were mainly the directly heated 300B, 2A3 and 845. Extended highs. Inside is above ,good construction.!!! The filament supply of the 300B is electronically regulated, and the plate (anode) current settings is done automatically by the amplifier. Russian Silver Mica, here 40 nF for C1. The First Series "030" (FS-030) is specifcally designed for use in sophisticated low-to-medium power single-ended circuits. There is more information about power supply design with tube rectifiers in the Power Supply Design for Vacuum Tube Amplifiers article. Schematic diagram of Hashimoto H20-3.5U Transformer use 300B Single Ended Amplifier on 20th Jan 2016 Note :When use 5AR4 for V4 power is around 8W rms max and 5U4G is 7 W rms max. For best performance you will want to used the best audio output transformers you can get your hands on. First DIY amp FINISHED - 300B SET - works. ... you set the cathode of the 300B to a high voltage (i.e. By reducing the size of R8 you can increase the B+, but note that the maximum anode voltage for the 300B triode tube is 450V. In my initial attempt I tried two 7805 voltage regulators in parallel for each channel but the current draw from the 300B heater filaments was too large for the 7805 IC. 300B based amplifiers offer the easiest access to and greatest choice within the SET topology. The 300B SE tested in the 300B PSE chassie. The choke is a Hammond 193J (10H, 200mA, 82 ohms) and the audio output transformers are Hammond 1627SEA. You should expect that the values of R7 and R8 will need to be adjusted slightly in order to achieve the target voltages shown in the schematic. It just does its job, period. Some three years ago, the T-Rex was born as an 8-wpc reference-caliber 300B-based SET stereo power amplifier, an amplifier that incorporates the design priorities deemed important by DO. Back to DIY and HiFi Audio Schematics, DIY 300B Single-Ended-Triode (SET) Hi-Fi Amplifier project, Power Supply Design for Vacuum Tube Amplifiers. I recently acquired a 300B SET amp to audition as a summer replacement for my two 845 SET amps which are space heaters. A pair of reasonably sensitive (>91 dB/1W/1m) loudspeakers will be required with this 300B SET amplifier. The finished amplifier is shown above in Photograph 7. Even within tube amplifier fans there are those who prefer push-pull over SET. It is honest and accurate and sweet and will drive a surprising number of commercial speakers to acceptable levels. this comment from Owner on 24th May 2018 Santiago,Chile he said seem like 300B SET… To adjust the B+ I introduced a resistor in the power supply (R8). the my new reference 300B Amplifier max performance to drive high efficiency loudspeakers started 16 february 2011. The frame is made from 20 mm thick MDF wood which was finished with spray primer and paint. Unbelievably, it had been almost 20 years since I'd last heard a 300B amp in my home system. Using a separate tube rectifier (5U4-GB) for each channel results in a decreased voltage loss across the tube rectifier. 6SN7 / 300B Single-Ended Tube Amplifier Schematic; 6SN7 / 300B SET Amplifier Build Thread; DIY 300B Single-Ended-Triode (SET) Hi-Fi Amplifier Project For the internal input cable wiring I used Mogami W2330 shielded interconnect wire. The circuit design is old school: Choke-loaded triode direct coupled to DHT driver, transformer coupled to the push-pull 300B output tubes. The other power supplies include the fixed bias ones: 300B SE Amplifier: Fixed Bias Supplies. The result is the "Fatboy" 300B amp - named as such because, like me, it is a tad overweight. With 3.5-W output power, this amplifier loves horn-based speaker systems. The speakers shown in Photograph 6 are DIY double horn enclosures with the Fostex FE207E fullrange driver. thread. PIO K40Y-9, 220 nF/1000V. To meet this criteria one must modify a cheap amp to make it better - otherwise a "proper" amp in the shop would cost at least 3000 dollars. Contact with voltages of this magnitude can cause serious injury or possibly be fatal. I have been using this amplifier for over 2 years now with no problems and this 300B SET amplifier continues to impress all who listen. - J.C. Morrison (1993). In my 6.4-m long × 3.4-m wide listening room, I deliver an enormous sonic picture, driving my back-loaded horn speakers. October 2nd, 2019, 12:07 am. R7 was adjusted from the original value of 27k to 15k to attain the target voltages. Photograph 6 below shows my first listening session with the 300B SET amplifier. A pair of these power amplifiers are a perfect mate for the Mentor pre-amplifier and a path to truly exceptional audio enjoyment. The voltages noted in Figure 1 are measurements from my 300B triode amplifier build and compare closely to the voltages shown on the original SE 300B schematic. So, the set-up could be Mundorf + VCap (RIAA) and Mundorf - or - VCap in the 300B amp. I was anxious to hear how a $1785 amp kit would … The power transformer and chokes are from a local manufacturer here in Greece and built to custom specification. Amp Design. 300B Single-Ended Triode (SET) Amplifier Schematic. For this SE 300B triode tube amplifier build I have used premium parts throughout, Lundahl audio output transformers and a DIY chassis. This was taken about 20 minutes after the units were powered up the first time. I'd like to thank the website for providing the schematics to build such a wonderful sounding 300B triode amplifier. It really is a pity you that you cannot hear for yourself how wonderful this DIY 300B SET amplifier sounds. The exact values and brands of the parts that I used for my SE 300B triode amplifier build are shown in Figure 1. When the EleKit TU-8600R single-ended 300B integrated amplifier arrived from Japan, I rushed to install it. The premium capacitors are very large in physical size so you will need to use a good sized enclosure for the amplifier. With the LT1085 regulator circuit in place the 5V filament supply was stable and the 300B SET amplifier was whisper quiet. Nov 4, 2016 - Stamou Tasos outlines the design and construction of a 300B single-ended triode (SET) tube amplifier following a single-ended (SE) tube amplifier schematic by J.C. Morrison. For this SE 300B triode tube amplifier build I have used premium parts throughout, Lundahl audio output transformers and a DIY chassis. The voltage at these test points will change slightly with different tubes sets so don't expect to match the shown voltages exactly. As it is the sound is quite similar to the sound 300B, suddenly it seems even better, it may be the enthusiasm of the novelty but it says a lot about the quality of this new amplifier. Additional photos and information is available on the forum in the First DIY amp FINISHED - 300B SET - works! The Canary Audio SET 300b M-80 is a mono-block amp that retail for $9,000/pair and puts out eight watts per mono block. Recommended are the Magnequest FS-030 audio outputs by Michael S. LaFevre. thread. I am really pleased with how the 300B SET amplifier build turned out both aesthetically and sonically. I find that I prefer the sound of the Russian PIO capacitors over that of the metalized polypropylene AuriCap. This 300B Single-Ended-Triode (SET) amplifier circuit uses a direct coupled 6SN7 driver stage. I spent a long time planning the layout of the 300B SET amplifier as you need to be careful so not to create ground loops in your amplifier build. See. Please take a look at the SE 300B schematic for a description of Mr. J.C. Morrison's SE 300B tube amplifier circuit which I will refer to as the "original schematic". The schematic shown in Figure 1 is for one channel only with the exception of the power transformer (T2) which is shared between both amplifier channels. 300B Amplifier Schematic. Specifically recommended in the circuit notes was that premium output transformers and components be used for the 300B amplifier build. Now set the meter for '95' and it is calibrated. It is honest and accurate and sweet and will drive a surprising number of commercial speakers to acceptable levels. It means, every available 300B tube can be … Hello, this is my first post, although visit these forums often. In the original SE 300B schematic a solid state filtered DC power supply is used for the 300B filaments. I haven't built any of those since a while, here is a new version of a single ended stereo amplifier which can use either a 45 or 2A3. The price includes a pair of … The single-ended 300B tube amplifier circuit will deliver about 8 Watts … Lundahl is a leading manufacturer of audio transformers and the Lundahl LL1623 transformers uses a special audio C-core. For improved performance an anode choke (L2) was been added to each channel. The top plate is made from a 4 mm thick aluminum plate. The power transformer (T2) has many taps specified as 400-0-400 @ 250mA, 6.3V @ 2A, 6.3V @ 2A, 6.3V @ 2A, 5V @ 3A, 5V @ 3A. The LT1085 regulated power supply circuit is connected to the 6.3V taps from the power transformer (T2). I used a separate LT1085 regulated power supply circuit for each audio channel. Re: 300B Amplifier Schematic October 5th, 2019, 12:11 pm To follow up later in the morning, just remembering you are using the 300B amp in a midbass horn (100-500 Hz), I believe I had slightly better results using a PP2A3 amp than a set amp on my setup. 300B SE - Single Ended (the little reference amp.) The bottom plate is made from a 2 mm thick aluminum plate. The 300B tube anodes are at 430V. Sound: Please do not ask by an email description about sound, but a little but we can say. 178 nF used for C3. A 300B “statement” amplifier for Real Serious 300B Fanatics (that’s a technical term!). Photograph 2 shows the 7805 regulators I initially tried for the 300B filament circuit. To improve on this idea I decided to use 5V integrated circuit (IC) voltage regulators for the 300B filament supply. So when you build it nicely, and also use the hints that are in the schematics, this amplifier has almost inaudible noise or hum. - Gio Militano (Editor). The driver stage is low noise schematic, and the heaters are all with DC. The MDF wooden frame and transformer covers were primed and painted with spray cans. I made wooden MDF covers for the Lundahl audio output transformers. Warning: This 300B SET amplifier project uses voltages which are in excess of the 400 Volt range. © Stamou Tasos and diyAudioProjects.com -, 300B single-ended (SE) tube amplifier schematic, 300B Single-Ended (SE) tube amplifier schematic with direct coupled 6SN7 input stage, grounding and shielding for your DIY audio projects. Guys, I want to build a 300B Amplifier. This amplifier, can be operated with every possible 300B tube available on the market. The LD+/Mk2 now offers universal flexibility to build with multiple drivers and output tubes. After building a 2A3 single-ended (SE) amplifier and retrofitting a set of 300Bs in place so I could compare the two types of output tubes, I was amazed at what a SE directly-heated triode (HT) amplifier could sound like. One on the power supply PCB (C11) and one in the amplifier board (C1) which is a massive 80μF/900V one. Back to DIY Audio Projects The hot air will rise and exhaust through the ventilation holes in the top plate (Photograph 5). Among them the 300B has the best sound. The power tranformer is a Hammond 278X (800V CT @ 230mA + 5V CT @ 3A + 6.3V CT @ 6A). You will notice that I have drilled a number of ventilation holes in the bottom plate (Photograph 4). An incredible sounding vacuum tube stereo amplifier--professionally assembled and tested--for about the same price as many kit amplifiers. The hum potentiometers protrude through the bottom plate so that you may regulate the noise from the 300B triode without having to open up the chassis enclosure. UPDATE  - April 2014 I also use WIMA DC Link film caps as the last caps. This is a great sounding 300B triode amplifier that I am sure DIYers will find to be very rewarding. You must follow your governing electrical codes for all grounding, wiring and connections. The finished amplifier is shown in Photograph 5. Full, deep, rich bass. Some things just work, and those who have heard the mighty 300B tube perform its magic through full-range drivers understand this. To further improve performance from this 300B triode amplifier the power supply filtering sections have been duplicated for each channel. inside of amplifier.very good and clean inside of amplifier. Design Elements The Legend Monoblock 300B-2A3 Parallel Amplifier is a true high-end amplifier, a beautiful It just does its job, period. This DIY 300B triode amplifier project was completed by Stamou Tasos who is from Greece. Stamou has built this amplifier with Lundahl LL1623 audio output transformers. Current (new) production 300B tubes like the Electro-Harmonix 300B and the JJ 300B sound wonderful at a fraction of the Western Electric 300B price. The Triode then drives the output transformer - TRANS-152. If you do not know how to build projects that have these potentials or you are not comfortable in with projects that use these high voltage levels, it is strongly recommended you do not built this vacuum tube amplifier. Dec 28, 2016 - This page contain electronic circuits about Electronic Vacuum Tube or valve Circuits Circuits and schematics. I have assisted by translating, formating and presenting his DIY 300B triode amplifier project. The circuit that I decided to follow for my 300B triode amplifier I found on this site, the 300B Single-Ended (SE) tube amplifier schematic with direct coupled 6SN7 input stage. Here is a picture of the completed amplifier and power supply chassis. - Gio Militano (Editor) Well I've made up my mind. I can now honestly say that I prefer vacuum tube amps (although I like tinkering with all types of audio gear). The schematic for the J.C. Morrison 300B Single-Ended Vacuum Tube Amplifier is shown below. We tested both triode amplifiers against Lowther DX3 horn speakers and Spicom Planar F3 (Dipole floorstanding speaker with 25"planar driver). For more information about grounding, see this helpful article about grounding and shielding for your DIY audio projects. For the small anodes chokes I specified 200H, 40mA (L1) and for the tube power supply chokes 6H, 225mA (L2). Using audio output transformers with a primary impedance of about 3000 to 3500 ohms you can expect about 8W of output with at about 2.5% THD. I have changed out the 0.22uF AuriCap (C3, Photograph 2) and settled in on new old stock Russian military paper-in-oil (PIO) capacitor k40y-9 (0.47uF, 630V) - Photograph 3. While the power transformer (T2) is shared between both channels, each audio channel has separate rectifier, chokes and filter capacitors. 300B Single and Parallel SET monoblocks are simply awesome! A direct coupled driver stage and an all low mu triode array are the specific reasons why this 300B SET design works so well. This 300B Single-Ended-Triode (SET) amplifier circuit uses a direct coupled 6SN7 driver stage. For more detailed information on tube rectified power supplies see these notes on vacuum tube power supply design. The Interstage transformer drives the Triode 300B in single ended mode. To see his build, visit the DIY 300B Single-Ended-Triode (SET) Hi-Fi Amplifier project page. This is the way to go. Elekit TU8600 Amplifier Kit. This amp is the quintessential triode amp. If you use the best available parts and materials in constructing it (as well as stash away a few tubes for a rainy day), it will pass down to your children and continue to wow 'em in the next millenium. UPDATE (2010-11-15) - the English translation Fundamental Amplifier Techniques with Electron Tubes is now available. 6SN7 / 300B Single-Ended Triode (SET) Tube Amplifier, 6SN7 / 300B Single-Ended Triode (SET) Tube Amplifier - Rear View, 6SN7 / 300B Single-Ended Triode (SET) Tube Amplifier - Underside View. For the 6SN7 driver tube I also tried NOS Sylvana and RCA tube brands, and I found that I like the sound from Tung-Sol brand tubes the best. As a thank you for the 300B amplifier schematics, Stamou has shared with us his implementation of the 300B single-ended (SE) tube amplifier schematic by J.C. Morrison. It is not necessary to use Western Electric 300B vacuum tubes. Elekit does this by providing two different sockets: one that fits 300B tubes, and another that is for KT88, 6550, KT66, KT77, EL34/6CA7, or 6L6GC tubes . The power supply use a 5U4-GB tube rectifier and a C-L-C filter. We made a direct comparison against the Sofia Electric SET 300B equipped with JJ 300B triode tubes. I was so eager to hear this 300B triode amplifier that I just had to have a listen before it was even complete. I have assisted by translating, formating and presenting his DIY 300B triode amplifier project. The amplifier comes in two chassis, one for the amp itself and a separate power supply. Note that I did not use the Hammond transformers shown in the Figure 2 Schematic. The output stage is a SE 300B triode and the maximum power output is about 8 Watts per channel. Good audio output transformers are the key to really outrageous performance. This 5V regulated power supply for the 300B filaments was posted by Suncalc and details about the regulated circuit are in the 300B SET Design Project forum thread. If would like to see some circuit diagram Schematic diagram for 300B Single Ended Amplifier. There are a million circuits available online but they are all designed for full range. – The input sensitivity is around 2V which is ideal for a power amplifier and ideal when mating with Audio Note's M3 Line pre-amplifiers. I'll find a suitable chassis and some greenlee punches and go from there. Please be sure to consider ventilation when you are planning your 300B triode amplifier build. The 300B SET amplifier was built using point-to-point construction. Chinese amplifier SET Music Angel XD845 with mighty 845 triodes EXECUTIVE BRIEF: In this page I describe how I searched the world for a tube amp that is easy to buy and everybody can afford it. The tube compliment was Electro Harmonix 300B Gold Grid, Electro Harmonix 5U4GB and Tung-Sol 6SN7GTB. At this point I don't have a clear understanding of the DC filament PSs but I'll cross that bridge when I get there. At this point, the amplifier had not yet been finished still requiring the transformer covers and ventilation holes in the top plate. In the end I was very pleased with how my chassis turned out for the 300B SET amplifier. The amplifier reveals a magnificent sound stage with warm sound and pleasant harmonics. More 300B Triode Amplifiers. This is where cool air will enter the amplifier. Photos of his build are shown below and additional information is available on the forum in the First DIY amp FINISHED - 300B SET - works! The chassis for the 300B triode amplifier was built by myself. I used Tango NC-14 interstage and FX40-5 output transformers, which I've had around for a while. Last update 28 April 2015.