Fake valves

[spendorman]

My late 303 is serial 83114, my early 303 is of very early production, v low serial number. All my 303's were fitted with 38494s, one 38414 failed, that was replaced with Motorola 2N3055H, yes the Langrex purchased 38494 is to replace the 2N3055H, but no rush to do that!

[spendorman]

The RCA 38494 arrived today from Langrex, measured it's Cob and found it to be 1287pF.

The Motorola 2N3055H's that I have measure in the order of 410pF.

This sort of ties in with Amp Lab's findings.

[southall-1998_mk2]

Sorry for the silly question. Are Langrex a good company to deal with? Are their NOS tubes genuine etc?

S.

[Jazid]

Yes, I've used them several times, all decent. You can 'phone up James if you want something odd or to ask about quality, provenance &c.

[southall-1998_mk2]

Smashing stuff James. Thanks!

S.

[karma67]

Yes, I've used them several times, all decent. You can 'phone up James if you want something odd or to ask about quality, provenance &c.

same here and they are only down the road from me,i bought NOS ec881 from them,had to take them back twice,the last time was to get my money back,they refunded me with no problems.

[spendorman]

same here and they are only down the road from me,i bought NOS ec881 from them,had to take them back twice,the last time was to get my money back,they refunded me with no problems.

That doesn't seem so good. but I suppose NOS could be unreliable.

[karma67]

That doesn't seem so good. but I suppose NOS could be unreliable.

i suppose these things happen,both times one tube out of the pair had a sort of wind rushing noise in the background,im no expert but shouldn't that have a result when testing which they say they do?

[spendorman]

i suppose these things happen,both times one tube out of the pair had a sort of wind rushing noise in the background,im no expert but shouldn't that have a result when testing which they say they do?

Testing may not have revealed that, the ear is super sensitive.

Some years ago I repaired a vintage valve amplifier, fitting a non standard output transformer, had to adjust the negative feedback. The good, amp worked, and measured OK using a scope and signal generator. The bad, listening tests proved that the repaired channel sounded different and inferior to the un-repaired channel.

[Jazid]

Often it's valve bases, or oxidised pins, and in the case of some WE 417a where I obviously wasn't in a rush to bin them the issue resolved itself (and for several years to date). So not perfect but NOS is a risk as it's old stock, and testing isn't perfect. I've had all sorts off Langrex and they have never been less than helpful and honest.

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