Eventually, I came up with a schematic, shown small in Schematic 1. I have analyzed many schematics, from a hybrid design with an E88CC voltage gain stage and a direct-coupled IRF610 MOSFET output stage to a design involving a 6080 or 6C33C-B as output stage in a cathode follower configuration.Schematic 1, (Click here to enlarge.) Ian has been very helpful to me with past tube projects, so I had a good look at that. The problem with many tube headphone amplifiers is the high output impedance and the low output current that decrease the sonic performance. Please visit my Tube Amplifier Forum Here's the place you can go to ask tube amplifier questions.Single Ended Tube Amplifier Circuit China-hifi-Audio online store : Pre-amplifier - Dussun solid Amplifier HiFi Audio Shanling Auido vacuum tube CD player.This article shows my tube headphone amplifier designs for driving headphones with an impedance of 200 to 600 ohms (I am using these amplifiers with the Sennheiser 580, which has a 300-ohm impedance). There are hundreds of pages of Tube amp information on my library page. The Tube amp Library of information Click the link above for Tube amp info, Schematics, Board building information, Projects, Mods, Transformer diagrams, Photo's, Sound clips.the bias current of the output stage should be enough for any music peak (20Vpp on 300ohm)The designs have been optimized using a SPICE circuit simulator with an advanced tube model by Mithat F. It is based around 12AU7 / ECC82 audiophile vacuum tube that provides warm, rich. no regulator tubes are used such as 6080 and 6C33C-B, because they are considered less linear9 hours agoThis is simple to build audiophile class-A tube headphone amplifier. Wikipedia 'The EL34 is a thermionic valve or vacuum tube of the power pentode type. Some electron tube devices rely on the properties of a discharge through an ionized gas.' Vacuum tube. 1 MULLARD 6BX6 EF80 Vintage Stereo Amp Vacuum Tube NOS NIB FREE.The hybrid with the IRF610 source follower does not have very good sound, the amp with the 6080 output stage has pretty high output impedance (more devices per channel would lower output impedance, but then the tubes must be carefully selected) and the 6C33C-B is not very linear for a headphone amp (but it is very good in an OTL amp for driving loudspeakers).Vacuum tubes mostly rely on thermionic emission of electrons from a hot filament or a cathode heated by the filament.
Vacuum Tube Amp Schematic For Free On UnixThe headphone amplifier circuits (figures 3a, 3b and 3c) use a single-ended triode class A gain stage and a paralleled-triode cathode follower output stage. The SPICE circuit simulator is available for free on Unix (Berkeley) and on Windows (WinSpice), and there are many commercial ports on Windows 95/NT. The real tube curves were generated with Audiomatica’s Sofia vacuum tube curve tracer. Here are the results for the E182CC (simulation in red, actual in white):The SPICE model is so close that it is sometimes difficult to see the difference between model and real tube curves.To reduce the distortion of the first version with E82CC/ECC82/5814 tube, I don’t have a bypass on cathode resistor to leave some local feedback, but you can try to bypass it with 220uF, 16V ELNA Cerafine electrolytic capacitor as with the other versions.The second version with the 3A5 (I used a RCA 3A5), a direct heating tube, gives less distortion and has a very liquid sound as only direct heating tubes can do. Each section of 5814 is biased at 4.42mA and dissipates 3.76W. It could be that other tubes of this same type such as the E82CC/ECC82 Mullard or Jan Philips will have better sound. I have tested the first version with a 5814 JAN Philips. It has good sound but with some distortion because noval (new 9-pin tubes) tubes are not very linear. Tube dampeners might also reduce the microphonic effect, but I have not tried them.In all versions, the output tube V2 is biased at 26mA per section (52mA combined) for a total dissipation of 6W (2x3W). I have mounted the 3A5 on a floating socket. Note: the 3A5 is sensitive to microphonics (if you touch the table where the amplifier is, you will hear a “gong” in the headphones). The third version with the a Jan Philips 6SN7 (that I now prefer) has a less liquid sound than the 3A5, but the distortion is very low and the bass response is fantastic! Sometimes during listening sessions with the 6SN7 I thought that the high frequencies were missing, but this is not true. ![]() I have designed 3 different power supplies – regulated, passive and cheap passive: Each supply has a timed relay that mutes the audio output until the tubes stabilize. This list of capacitor sources is very useful for finding the right shop:About the power supply, the filaments can be powered by AC or DC except that the 3A5 (version 2 of the amplifier) requires a DC filament supply. So make your choice! In this design, the output capacitor of the power supply and the output capacitor of amplifier can be replaced with 220uF or higher value MKP types or other audio types. In listening tests, the MKP has an inclination to smooth out contrasts. At this time, I am using the ROE electrolytics and the SOLEN MKP. The supply in figure 5 is all-passive with inductors (higher cost). The BUX48 should be heatsinked to dissipate about 6W. The MOSFET/NPN pair can conduct up to 400V at 15A and will easily handle the surge currents of large power supply capacitors. Dns jumper free downloadThe slow-on supply will also increase the life of tubes! The MJ15004 should be heatsinked to dissipate about 12W.Full-sized PC board layouts are available for the slow-on power supply and the audio output mute circuits as well as the copper boards for mounting the Allen Bradley resistors. Also, this circuit is excellent for the 3A5 of version 2 of the amplifier, which requires a DC filament supply. See the amplifier schematics (figures 3a and 3b) for details about wiring the relay connections.This amplifier runs quietly without a DC filament power supply, but for a more stable filament voltage, I suggest the slow turn-on supply (figure 7) to replace the filament supplies in figures 4 and 5 (the cheap passive supply already has the slow-on circuit). Load) with a coil resistance of about 150 ohms. The relay is a 12VDC DPDT (7-10A max. Added layout diagram for mounting 7x22K resistors (figure 3c) and suggested chassis layout diagram (figure 7). Updated slow-start filament supply (figure 8). Also corrected value of R7 and fixed spelling of DCC90 name for V1 tube in version 2 of amplifier.9/29/98: Updated version 2 amp schematic (figure 3b) – added R8, R9. Also added a “cheap” version of the passive supply (figure 6).9/22/98: Added version 2 of amplifier schematic (figure 3b) and revised power supply schematics (figures 4, 5, 6 and 7).9/24/98: Added Rin to both amplifier schematics (figures 3a and 3b) and removed 6VDC output from slow-start power supply schematic (figure 7). Updated figures 4 and 5 power supplies: grounded filament supply and removed connection point “E” from amplifier schematic (figure 3). THD = 0.88% with Vout = 9.5v on 300 ohm => 200 mW0.40% with Vout = 5.9v on 300 ohm => 80 mW “MAX POWER FOR Sennheiser 580”0.17% with Vout = 2.9v on 300 ohm => 15 mw0.07% with Vout = 1.2v on 300 ohm => 2.5mwThe graphs in figure 9 are the THD (distortion) decays for the standard amplifier at 9.5V, 2.9V and 1.2V: PERFECT! They show a linear harmonic decay (and the lower the power, the lower the distortion).9/17/98: Updated figure 4 regulated supply: replaced single MOSFET with MOSFET/BJT Darlington pair to better handle surge currents from large output capacitors. Republished with permission. Also added notes re heatsinking BUX48 and MJ15004.For commercial use of the circuits in this article, please contact Andrea Ciuffoli.From Andrea Ciuffoli’s Home Page.
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