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Audio and Video Talk
Valves / Vacuum Tubes
QUAD II (old old stock): Alternatives to KT66?
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<blockquote data-quote="Ampdog" data-source="post: 499627" data-attributes="member: 144"><p>Entropyagent,</p><p></p><p>To support what Charles said with some further information:</p><p></p><p>Some will say certain replacements are in order simply when the amplifier will make a noise with said replacements. Never mind mangling original characteristics.</p><p></p><p>When one is rather higher up the food chain than simply accepting that resulting sound denotes proper valve replacement: The EL34 is different from beam valves like KT66 and the 6L6 family (6L6GB, 5881, 6L6GC, 6L6Wxxx ....), apart from overheating the already fragile power transformer. (An aside: I have yet to read of a real reason for preferring an EL34 to e.g. 6L6GC.)</p><p></p><p>Thus, yes. In Quad II the KT66 dissipates only 20W plate plus screen heat, thus a 5881, 6L6GB, 6L6Wxx and 6L6GC are all suitable - use the cheapest type available at any time. The characteristics of the 6L6 family and KT66 are within 10% of each other - closer than the production spread of either valve. Small differences in output valve characteristics are swamped by the Quad II output stage design.</p></blockquote><p></p>
[QUOTE="Ampdog, post: 499627, member: 144"] Entropyagent, To support what Charles said with some further information: Some will say certain replacements are in order simply when the amplifier will make a noise with said replacements. Never mind mangling original characteristics. When one is rather higher up the food chain than simply accepting that resulting sound denotes proper valve replacement: The EL34 is different from beam valves like KT66 and the 6L6 family (6L6GB, 5881, 6L6GC, 6L6Wxxx ....), apart from overheating the already fragile power transformer. (An aside: I have yet to read of a real reason for preferring an EL34 to e.g. 6L6GC.) Thus, yes. In Quad II the KT66 dissipates only 20W plate plus screen heat, thus a 5881, 6L6GB, 6L6Wxx and 6L6GC are all suitable - use the cheapest type available at any time. The characteristics of the 6L6 family and KT66 are within 10% of each other - closer than the production spread of either valve. Small differences in output valve characteristics are swamped by the Quad II output stage design. [/QUOTE]
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Audio and Video Talk
Valves / Vacuum Tubes
QUAD II (old old stock): Alternatives to KT66?
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