Searching on the internet, i could find what i can only call gimmick designer amps and second hand guitar heads. This text attempts to explain how the design decisions were made and describe the design. With a total anodeplusscreen dissipation of 28 watts, when operated with cathode bias, its power output, in pushpull. Kt88 distortion at 30w with 10db feedback and vin0. Gotta replace power tubes in my cary monoblocks any. Testing and measurements monoblock kt88 pushpull tube amp kit. C, remodelled the tt21 transmitting tube, naming it kt88. The humble valve amp pretty much defined the sound of guitar music from the 50s onwards. Octal valve retainer kt88 6550 valves sockets this is an octal tube retainer for kt886550 types. The wd kt88 amplifier, in both forms is excellent, but i would spend the extra on the xl version. Even if the phase inverter is perfectly balanced it will inevitably go out of balance when the power. The mainstay of high power valves for valve amps over the past 50 years, most high end hifi and guitar manufactures have built, or have an amp capable of running the kt88 ampeg, audio research, beard, carey, conrad johnson, mcintosh, marshall, rouge audio, sonic frontiers, mesa boogie etc. The new kt88 is a pentode with a higher anodeplusscreen dissipation of 40 watts, and a higher mutual conductance of 11 mav.
All menu of my experiment valve amplifiers and solid state of this site. Pp2012 kt88 hiend push pull amplifier audio design guide. If you have not been trained to work with high voltage then have an amp technician service your amp. May 20, 2010 this 7 page chapter on valve amps is centred on understanding the operation of the williamson ultra linear 100 watt valve amp. Kt88 s can be put in the 1959hw with some modifications to the bias circuit, yes. The vt is going to make life a lot easier from now on. The current tubes are golden aero kt99s, rare and probably unobtainable at this point. Design and construction of a pair of pushpull classa, ultralinear mono block tube amplifiers that can be used with several different power vacuum tubes including pp tube amp kt88 pp tube amp see more.
Transformer winding is an extension of the fitting and turning industry. Diy 12sl7 srpp pushpull kt88 tube amp diyaudioprojects. Well, radio building master greg charvat has you covered with his latest presentation, design your own vacuum tube audio amplifier. With this valve it is therefore possible to build amplifiers having higher power outputs suitable for publicaddress equipment and highquality sound reproduction in general. I was asked by kegger on the ak tube amp audio forum if i was interested in designing a pcb based amp on the 6l6 output tube family. With an anode to anode load of 4,000 ohms and 550 volts on the anode a pair run in ultra linear ab1 will deliver 100 watts at 3. But i need more information about valves and what valveparts i should look for when it comes to sub bass. See more ideas about valve amplifier, tube and vacuum tube. I set the amplifier using vacuum tubes of different types in the same circuit this time. I think it can vary by the amp design, but for my line magnetic, the el34s sounded like what id always pictured a tube amp sounding like, where as the kt88 s had a little more of the force and slam of solid state. Class ab1, 12 x 6550 per channel, very basic details. Specifically designed for audio amplification, the kt88 has similar ratings to the american 6550 which was designed for use as a servo amplifier. Classa ultralinear 12sl7 srpp kt88 sipp tube amplifier.
The amps are cary audio slm70 monoblocks made in 1991, each amp using four power tubes. But the design centre value should be about 400 volts or less. Anyone know off hand what the power requirements are or where i would find the information. My amp came in el34 and kt88 versions, and i picked the former. For many years the kt66 valve has been regarded by many as the hallmark of a highquality amplifier whether home made or commercially manufactured. Tube rectifier in doubleend amp power supply sag sustain. They are usually used for relatively small amplifiers, e. Glassware tube audio design software including free curves software. As musical tastes transformed from big band to swing to jump.
The valve wizard single ended how to design valve guitar. Final connections kt88 tube amp kit tube, audio, amp. Professionally built from allens schematic by local amp builder and classicsound. Its quite nice looking, especially if you like wood. Not changing it will both shorten the life of the tube probably dramatically and also not allow the kt88 to be run close to their design ratings. The valve wizard pushpull how to design valve guitar. Group a consists of kt77, 6ca7, el34, 6l6gc and similar variants. Theres an air of magic surrounding a valve amp thats had its valves on for a couple of hours it just sounds incredible. This page describes a low power single ended audio amplifier.
Oddblocks classa pushpull kt88 tube amplifier 12sl7. Benefitting from the extra headroom of the kt88, the studio 10 kt88 is the pinnacle of dynamic modern cleans and tight highgain overdrives. The subject amplifier is a medium power monoblock design, based on triode connected kt88. An inexpensive, easy to build diy valvetube tester for quite some time i have been looking at developing a design for a diy valvetube tester that is easy to build and uses readily available, low cost parts. It was absolutely, systematically and thoroughly pulverised sonically by my 211 parallel single endedbased amps. 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. By way of legendary amp engineer ed jahns, fender would produce the most powerful production tube amp ever made, the fender 400 ps. The slides are pretty heavy on engineering design terms, but give a good feel for what it takes to construct and tune an audio amplifier using vacuum tube. However, guitar amps rarely use matched valves and usually have a lessthanperfect phase inverter. Single ended class a 6v6 6j5 valve vacuum tube amplifier circuit. The orange vt valve tester will become an essential piece of kit for the professional guitar amp technicians workbench. Kt88 s sovtek vs valve art audiogon discussion forum. This amplifier was featured on the february 2004 issue of the highfidelity audio.
Bad anyway,but this web site is not english program site. Im interested in letting someone build a kt88 pre amp just for this purpose. For design purposes i found that potential power tubes pretty much fell into two groups. See more ideas about valve amplifier, electronic schematics and vacuum tube. Gio writes in to tell us about his latest vacuum tubebased audio amplifier design, the 5751 srpp pushpull tube amp. Never touch the amplifier chassis with one hand while probing with the other hand because a lethal shock can run between your arms. Create innovative programs and fun games on your tiny yet powerful raspberry pi.
Tube bias calculator rob robinettes car and tube amp website. Assembly manual schematic parts list tubes and applications design simulations. There are a lot of testimonial forms for the el34 valve amplifier, which is an older and more established model. Mike clementtech for tony iommi, david gilmour band, motorhead, iron maiden, jeff beck band. Using only a pair of kt88 i have got 25w in triode connection and 3540w using the. The amplifier stage is based on the compact hifi power amplifier by melvin leibowitz. Allen wright design class a kt88 tube amp, built by.
Icon audio stereo 25 mkii integrated amp based on st40 mkiiim icon audio created the handmade stereo 25 mkii integrated tube amplifier with the goal of making it the easiesttouse, lowestmaintenance, and most powerful highend. Our el34 valves and kt88 valves will tolerate much higher voltage, so we have a big safety margin, and we can give 2 years guarantee for our el34 and kt88 valves in our amplifiers. The valve amp hospital vintage amp repairs a gec kt88 batch date 7307 1973july. We have set new goal to implement the newest true balanced circuit topology from input stage, driving. By trying out several different sets of operating conditions in the computer i could eliminate hundreds of possibilities without playing with electricity.
These amps give the warmest and truest guitar tone that players around the world still love today. Studio 10 kt88 is driven by the monumental kt88 power amp valve and an ecc83 in the preamp stage. Most valve amp manufacturers have a basic academic understanding of output trannys, but often. Kt88 valve amplifier project 3d cad model library grabcad. When building high power valve amplifiers, using multiple kt88 output valves in push pull is preferable to using 2 very large valves, as an ht power supply requirement of 560v is very easy to achieve and output valve failure will not cause the amplifier to shut down, as at least 2 valves would have to fail in each half of the push pull output. It is one of the largest tubes in its class and can handle significantly higher plate voltages than similar tubes, up to 800 volts. Front lcd is controlled by a micro controller which can be software upgraded at later time to. General view of the 8850 amplifier with left its complementary pre amplifier. Icon audio stereo 25 mkii integrated amp kt88 demo. For a 2x kt88 guitar amp, you would have spectacular rich cleans, and some rather chest pounding power wide open, with the right speakers, in the right circuit. Kt88 tube power amplifier class a single ended valve triode amplifier has not same tone with push psu amplifier.
With the kit supplied jan philips 5751 drivers and genalex gold lion kt88 output tubes the sound was superb. Kt88 distortion and frequency at 25w with 16db of feedback vin1vrms. The kt88 is one of the few classic audio output valves. Using only a pair of kt88 i have got 25w in triode connection and 3540w using the ultra linear configuration.
After balancing the bias i hooked up the amps to a pair of back loaded horns with fostex fe206e drivers 96 db 1 w and checked for hum. The poddwatt is a small classa stereo vacuum tube amplifier that will provide about 5 to 7 watts of high quality sound. Listening impressions odd block kt88 tube amp kits. The kt88 is a beam tetrode k inkless t etrode hence kt vacuum tube for audio amplification. The response is very smooth, there is plenty of detail and that wonderful warm tube sound. This power could be considered low for a pair of kt88 but i want low feedback, low distortion and good damping factor. I dont own any valve arts but something tells me they are chinese valves. Kt88 valve amplifier project likes 3d cad model library. The kt88 audio tube is considered to be one of the best sounding power tubes for hifi tube audio amplifiers. This will be enough to bias the valve almost to cutoff, and we dont really need more than that. To get the best sonic result there are no electrolytic capacitors on the signal path and in the anodic power supply. Ever wonder what goes into the design of a vacuum tube audio amplifier.
Im so blown away with the tone quality of my 4x kt88 reeves 225 running guitars, that i thought it would be quite cool to do a 2x kt88 version to make it just a smidge safer on the ears. The amps will also work with el34, 6550, kt88, or kt90 tubes. The output of this small amplifier in which a 6v6gt output pentode is connected as triode is about 4. A tube amplifier chassis contains lethal high voltage even when unpluggedsometimes over 700 volts ac and 500 volts dc. Group b consists of kt88, kt90, 6550 and their variants. Oct 14, 2016 the kt88 is one of the few classic audio output valves. Im very satisfied with my ab1 jolida p with vintage siemens tubes in it its really a heavenly amp to drive my ar3as. The minimum for acceptable kt88s in a good power amp in my pompous opinion is the jj tesla, a little more laidback than the svetlana, but i reckon the svetlana will suit the character of the power 3s better. Looking at the ax84 website, they have a schematic that would work for an el84, 6l6 or kt88.
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. Debuting in 1969, the 400 ps was a behemoth conservatively rated at 435 watts rms. A perfectly balanced pushpull stage will cancel all even harmonic distortion and sum odd harmonic distortion generated within the power stage. The kt88 fits a standard eightpin octal socket and has similar pinout and applications as the 6l6 and el34. The figures given are for single ended use, but the valve is almost invariably used in push pull pairs.
Designed and manufactured by our own great british company the gecmo valve co, she is one of the best. For years i have been using a valve tester that i had developed in the past. Few people working in transformer winding companies have a knowledge of electronics or valve amps. Design and construction of a pair of pushpull classa, ultralinear mono block tube amplifiers that can be used with several different power vacuum tubes including el34, kt77, 6l6gc, 6550, kt88, kt90. El346550kt88 single ended amplifier on 28th mar 2018. Tube bias calculator rob robinettes car and tube amp. Higher powers are obtainable with either very large power valves, or by using multiple valves in parallel, but beyond about 15w it is usual to use. This is a set of 6 matched kt88 jj tesla specially selected for the ampeg svt. From andrew champ cba 200200 stereo 8 x kt88 amp august 2011 i wanted to replace a 400 watt valve amp that i had custombuilt back in the early seventies but hadnt owned for many years. Valve technology is now redundant and there is no point discussing valve amp designs that fall short of achieving the highest performance for replicating music. The difference is in both the bias voltages and maximum power dissipations. Valve amp manufacturers purchase trannys from transformer winding companies. Kt88s can be put in the 1959hw with some modifications to the bias circuit, yes.
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