science

KT88

KT88 is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand KT88 rather than just read about it. In short: The KT88 is a beam tetrode/kinkless tetrode (hence "KT") vacuum tube for audio amplification. Features The KT88 fits a standard eight-pin octal socket and has similar pinout and applications as the 6L6 and EL34.

Key takeaways

KT88 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect KT88 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of KT88 from memory before moving on to harder problems.

Reference excerpt

The KT88 is a beam tetrode/kinkless tetrode (hence "KT") vacuum tube for audio amplification.

Features The KT88 fits a standard eight-pin octal socket and has similar pinout and applications as the 6L6 and EL34. Specifically designed for audio amplification, the KT88 has higher plate power and voltage ratings than the American 6550. It is one of the largest tubes in its class and can handle significantly higher plate voltages than similar tubes, up to 800 volts. A KT88 push-pull pair in class AB1 fixed bias is capable of 100 watts of output with 2.5% total harmonic distortion or up to about 50W at low distortion in hi-fi applications. The transmitting tubes TT21 and TT22 have almost identical transfer characteristics to KT88 but a different pinout, and by virtue of their anode being connected to the top cap have a higher plate voltage rating (1.25 kilovolt) and a higher power output capability of 200 watts in class AB1 push–pull. The screen grid is sometimes tied to the anode so that it becomes effectively a triode with a lower maximum power output.

History The KT88 was introduced by GEC in 1956 as a larger variant of the KT66. It was manufactured in the U.K. by the MOV (Marconi-Osram Valve) subsidiary of G.E.C, also labelled as IEC/Mullard, and, in the U.S., Genalex Gold Lion.

As of 2022, KT88 valves are produced by New Sensor Corporation (Genalex Gold Lion and Electro-Harmonix brands) in Saratov, Russia, JJ Electronic in Čadca, Slovakia and Hengyang Electronics (Psvane brand) at former Guiguang factory in Foshan, China. NOS examples in good condition are extremely rare. Due to its availability and characteristics, the KT88 is popular in hi-fi production amplifiers. Historically, it has been far more popular with high fidelity stereo manufacturers than guitar amplifier builders, given its characteristics of high-power and low-distortion. Due to these characteristics, it is regularly used to replace 6550 tubes by end users seeking a guitar amplifier tone with less distortion. Some of the amplifiers which shipped with the KT88 power tube include the Hiwatt, Marshall Major, and some Ampeg models.

Characteristics

See also KT66 KT90 6L6 6CA7 / EL34 6V6 807

References

External links Reviews of KT88 tubes. Tube Data Archive, thousands of tube data sheets

Illustrations

Worked examples

Example 1 — a first encounter with KT88

Start with the simplest possible case. Write down what KT88 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to KT88 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about KT88 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of KT88

In research: KT88 appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses KT88 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: KT88 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Audiovisual introductions in 1956, Guitar amplification tubes, Vacuum tubes, so understanding it makes those chapters shorter.
In everyday life: Look for KT88 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study KT88 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what KT88 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain KT88 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is KT88 in simple terms?

The KT88 is a beam tetrode/kinkless tetrode (hence "KT") vacuum tube for audio amplification. Features The KT88 fits a standard eight-pin octal socket and has similar pinout and applications as the 6L6 and EL34.

Why does KT88 matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study KT88?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on KT88.