I found gold lion kt88 to sound very good in my primaluna dialogue premium versus other kt88s. Classa ultralinear 12sl7 srpp kt88 sipp tube amplifier. Dc circuit, circuit diagram, electronics storage, electronics projects, electronics gadgets, speaker box design, valve amplifier. Introduction those who know me may be surprised to see an article on a vacuum tube amplifier written by me. The kt66 and kt88 were and still are highly regarded wherever tubes were being used to amplify sound. Icon audio created the handmade stereo 25 mkii integrated tube amplifier with the goal of making it. However, there are problems with nutube 6p1 which makes it useless in audio systems with high fidelity.
We have been working at sourcing a good quality kt88 tube for the past couple years. The designs included here cover applications from a simple amplifier for home use to very large units for public address in auditoriums and stadiums. A tube amplifier chassis contains lethal high voltagesometimes over 700 volts ac and 500 volts dc. Keywords audio, low frequency, thd, noise, vacuum tube, circuit design, pcb design. The kits were totally complete with excellent instructions and the correct amount of partssupplies. C, remodelled the tt21 transmitting tube, naming it kt88. The obvious choice is to use a common low cost audio tube like a 6l6, kt 88 or an el34 strapped for triode operation. Most of this glorious tone was delivered by pushing those amps hard and causing the output tubes to distort, or breakup. My ears never rang after listening to that, no matter how loud. The c70 kt 88 vacuum tube stereo ampli7er bob cordell 1.
Vacuum tube kt88, electroharmonix antique electronic. A pair of pushpull class a, ultra linear mono block tube amplifiers that can be used with several different vacuum tubes including kt77 6l6gc kt88 with a 12sl7 driver and 6no30 tubes. The book offers more than power amplification, however. Diy vacuum tube valve amplifier projects hifi audio. An approach to audio frequency amplifier design by gec co. Nutube 6p1, is a vfd which was designed to use it as a double triode. The power amplifier involves three stages, two of which use a 12ax7. Kt88 single ended tube amplifier build 2018 part 4 youtube.
Kt88 is a low distortion, high output power tube developed specifically for audio. For the first time ever a kt88 tube utilizes a solid, thick and completely unique graphite plate anode. Nobsound 300b monoblock vacuum tube integrated amplifier. Recommended books for audio and stereo repair and design duration. Icon audio stereo 25 mkii integrated amp kt88 shop. General electric uks fabled lab and production plant began to scale back operations. The values for the acceptable range of ma are easily calculated from the max power for the tube type and the design voltage for the tube. I hope this post makes the design goals i follow herein crystalclear, to avoid continued confusion by any of the traditional by the book thinkers.
Reisong hifi audio amplifier mt88 mkii kt884 vucuum tube. If you want to see some data look at morgan jones book building valve amplifiers, which is very much why many people began to look at carbonized glass coatings again. Today, there are a number of quality kt88 tubes available for audio and guitar applications. With the voltage below 400 vdc i can go from a 6v6 to a kt88. A survey of 4 sets of tubes in 2 pushpull amps by steve graham. I grew up listening to music played through my parents fisher 500c stereo receiver, a tube amp from the early 1960s that did wondrous things to albums like let it bleed by the rolling stones when played at very high volumes. The kt120 already draws a bit more heater current and plate current than the kt88, so that is a concern for some amps but most will find the kt120 a dropin replacement. In order to achieve this i decided that an octal based output tube would give me the greatest variety. Beside that, el34, el84, and 12ax7 vacuum tubes are used in many practical examples, to design the various parts of the circuits and to. If you have not been trained to work with high voltage then have an amp technician adjust the amp s bias.
Universal loadline calculator for vacuum tubes vacuum. Aug 9, 2011 this pin was discovered by esther ostolaza. Nobsound hiend kt88 valve tube amplificateur stereo hifi audio power amp. In order to change tubes on the fly i had to go with a cathode biased design. Basic theory using 21stcentury technology to design vacuum tube preamps, power amps, and power supplies system design a professional methodology for crafting a complete guitar amplifier. The preferred series kt88 construction features a solid plate design and triple getters. You then insert the tubes and take a reading, adjusting the pots from the top of the amp. Factory matched quad tube amp doctor tad kt88 6550 for tube amplifiers citation ourfavorite tube in the kt88 6550 class. Jean hiraga singleended tube amplifier schematic with input stage dc circuit.
Oddblocks classa pushpull kt88 tube amplifier 12sl7. Several years ago i needed a vacuum tube amplifier to compare with solid state designs for use in lis. For books on the subject of vacuum tubes, see our diy audio book. Reisong a20 hifi intergrated amplifier kt88 tube singleend class a 4nd vu meter. Step by step design of a pushpull vacuum tube amplifier. I used the previous edition to design and build the sea amplifier i used a couple of marconi vintage nib kt88 for the two channels.
Electroharmonix kt88 vacuum tube high power kinklesstetrode for use in amplifiers such as the marshall major. Classa pushpull tube power amplifier electronics diy. A good few months ago back in 2010 i received an outoftheblue phone call which is quite often the case regarding enquiries like this from a really nice gentleman named andrew. People wanted their amps to breakup at lower volumes, and more severely than they had in the past.
The power amp transforms the carefully crafted signal voltages served up by the preamp stages into the punch and sizzle that defines a guitar amplifier s character. See more ideas about valve amplifier, vacuum tube and circuit diagram. The monoblock tube amp kits arrived about two weeks after placing the order in two double boxed packages, each package weighing about 6. This improves tube life and reliability on top of providing outstanding audio amplification characteristics. Diy kt88 pushpull monoblock tube amp kit 30 november 2009 canadian flag kit.
The latest version of our tad kt88str is built in the style of the early british mov kt88. It is one of the largest tubes in its class and can handle significantly higher plate voltages than similar tubes, up to 800 volts. For technical books, tube data, vintage data, transformer data, and mcintosh. No, i didnt powerup with one of each installed and yes, i had four of each of the above tubes for the shootout. Psvane cossor kt88 vacuum tube replace 6550 kt88 tubes black bulb hifi audio diy. The amplifier stage is based on the compact hifi power amplifier. The amplifier stage is based on the compact hifi power amplifier by melvin leibowitz. Gec audio tube data by gec circuit designs code 2003. Tube matching, bias and breakup how they work together. Specifically designed for audio amplification, the kt88 has similar ratings to the american 6550 which was designed for use as a servo amplifier. The kits were well packaged and there was no damage to the contents. A straightforward design based on the british companys awardwinning st40 mkiiim that. Following is a list of must have books for the serious tube amplifier designer.
Design my design involves a fourstage preamplifier, which uses two dualtriode 12ax7 tubes. Atarashi modified the amplifier to fit for kt 88 ab1 pushpull ultralinear operation. In general, the kt88 tube has a magical midrange similar to the smaller el34 tube, but with low and high end extremes that reach much further. Having the ability to runs different output tubes was one of my design goals. Kt88 pp tube amp valve amplifier, amplifier, vacuum tube. Bg198 part 4 in our series on the kt88 single ended amplifier build.
At the beginning of the year, i found this interesting scheme of tube amplifiers on a forum and decided to make it. Buy mullard tube circuits for audio amplifiers by mullard isbn. The tool is just a couple of octal sockets with pins and a lead each that you insert into the power tube sockets. I have a pair of diy pp parallel monoblocks that run the output tubes at 60ma class a1. Muzishare x7 kt88 x4 pushpull vacuum tube integrated amp power amplifier mm phono amp remote upgrade.
Hifi kt88 vacuum tube amplifier singleended class a stereo. This kt88 has excellent quality and for the price is one of the best kt88 in production today. This amplifier was featured on the january 2003 issue of the highfidelity audio. Other sweep tubes were considered, but the same concerns apply to them as well, and some of them have become expensive. This guide discusses all relevant aspects for an integrated pushpull vacuum tube amplifier design, including the power supply unit. Jean hiraga 12ax7 single ended kt88 tube amplifier schematic. I dont know much about harmonics, but i can vouch for the sound quality of tube amplifiers. Instruction book for specimen single ended stereo tube amp 62718. This doesnt mean they sound bad in another amp so im not trashing the tube. Icon audio stereo 25 mkii integrated amp based on st40 mkiiim. These darker tubes here are copies of the 150 also an ugly design, not that that matters for sound quality and thus the remarks about higher current.
One thing about diy audio is that it is a journey, not a destination, it never ends. This classa pushpull tube power amplifier uses a pair of pushpull class a, ultra linear mono block tube amplifiers that can be used with several different vacuum tubes including kt77 6l6gc kt88 with a 12sl7 driver and 6no30 tubes. The following pages of this chapter will describe how a williamson ul class ab ab1 amplifier works and how valve amps can be serviced and maintained to give the best performanse. A bibliography of must have tube electronics books. Due to the high current and power capability of these tubes, it is very important that the kt88 tubes are well matched. The kt88 fits a standard eightpin octal socket and has similar pinout and applications as the 6l6 and el34. Some of them are long out of print, and can only be obtained from used book sellers, although they are occasionally seen for sale on the internet. Nobsound hiend kt88 valve tube amplificateur stereo hifi audio.
Vacuum tubes mullard reissue antique electronic supply. Atarashi originally built this amplifier as the fixed bias el34 class b pushpull monaural amplifier featured on the january 2003 issue of the highfidelity audio. Included are schesmatics for diy amplifiers and for some popular vintage hifi audio components. Vacuum tube circuit design guitar amplifier power amps. The first electronic amplification of sound was done with vacuum tubes. Gec audio tube data by gec circuit designs code 2003 as demand for vacuum tubes waned inevitably in the 1970s due in large part to the advances in semiconductor technology. Psvane uk kt88 vacuum tube replace 6550 for vintage hifi audio tube amp diy 2pcs. Pete milletts diy audio pages for technical books, tube data, vintage data, transformer data, and mcintosh data, go to. Anyone who has an amp that is hard on output tubes should consider trying these. Modern vfd vacuum tube demonstrated itself as a tube which can provide tube sound with low supply voltages.
Buy products related to 6550 tube products and see what customers say about 6550 tube products on free delivery possible on eligible purchases. Whats the best kt886550 tube discussion in amps and cabs started by kramerxxx, jul 22, 2010. After design of layout i ordered the necessary parts. Kt88s can sound different depending on the amps design. From the phase inverter input to the loudspeaker output, every aspect of circuit design is rigorously explained and thoroughly explored. Maynard, i appreciate your contributions a whole lot thank you. And as for the power tubes, the amp is crazy loud but.
From the book build your own audio valve amplifier by rainer zur linde. Pushpull kt886l6el342a3300b amp with universal driver. Icon audio stereo 25 mkii integrated tube amplifier kt88 integrated amp. The ideal choice would be to design an amplifier that could accept any of these tubes without modifications. The worst was preferred series from the tube store. The amp was presumably designed to sound good with kt88. The kt88 audio tube is considered to be one of the best sounding power tubes for hifi tube audio amplifiers.
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