Question about Groove Tubes EL34s...

[CDawg]

I seem to recall (but could be wrong) that at one time Groove Tubes was going to get into tube manufacturing themselves and may have purchased the remnants of the old GE plant in Kentucky (I think). Yes, my post is full of disclaimers as to veracity, but that's what I recall. So if that's the case, they may have had either old GE parts or may have even started making some of the internal components again but never got the full manufacturing of complete tubes off the ground, hence having some stuff to send to China for completion.

I've heard a lot of those same things over the years. I don't know what's fact or fiction but it's probably something in between.

 

[Jon S]

I just got a quad of NOS Groove Tubes EL34M tubes. One of the tubes has a dark spot on the top of the tube where the getter is. IS this a cause for concern?

 

[ceylon]

I just got a quad of NOS Groove Tubes EL34M tubes. One of the tubes has a dark spot on the top of the tube where the getter is. IS this a cause for concern?

this is 1/2 a guess and 1/2 a deduction, now, but i think it means its been run hard.

whered u get them? ever since this post ive been wantin a quad (or ar least a pair)
for my marshall.

 

[Bill Ferris]

I just got a quad of NOS Groove Tubes EL34M tubes. One of the tubes has a dark spot on the top of the tube where the getter is. IS this a cause for concern?

What does the Maxi-matcher tube tester`s performance values indicate compared to the other 3 EL34M of the quad ?

That`s what initially I would go by with my Maxi-matcher, with a follow up test of all the tubes on my Amplitex AT-1000 tester, with its more complete indicating tube`s testing perimeter`s values results for my judgement of the tubes heath.

 

[Jon S]

I talked to the seller. He said it's not an issue but happens when the tube is heated up during the vacuuming process. He said some tubes getters will turn completely black during the induction heating process. In a way it's a good thing because the vacuum in the tube is stronger than normal. As I mentioned the tubes are new old stock and never used so it cannot be burned from use. The tubes were the later manufactured tubes as the Groove Tubes logos were imprinted on the glass envelope instead of the older Groove Tubes paper labels.

I tested the tube in the MaxiMatcher and there were no issues and the readings were comparable to all the other three tubes in the quad.

 

[Jon S]

where'd u get them? ever since this post ive been wantin a quad (or ar least a pair)
for my marshall.

You can find get them from Watford Valves in England. They sell for GBP£36.00/each or approx USD$50/each. They ship only via UPS Second Day and my tubes cost me ~GBP
£57.00 or about USD$75 to ship or total USD$275 for a set. The seller said that he met Aspen Pitmann when he introduced the GT EL34M tubes. He liked the tubes so much he made a large purchase of said tubes from Pitmann and he still has some stock of tubes left. If you contact them, note that he takes a while to respond as well as a while to ship (~7-10 days). It appears it is a one man shop as they close when he goes on holidays (I tried contacting them in September and did not get a response for a month. I almost gave up on them. He finally responded and said they were closed for vacation)

The good thing is that they test all tubes before shipping, so that is one reason why there was a delay in shipping. The other thing is that they package the tubes in generic tube boxes, not the retail GT boxes, which is a good thing. The original GT boxes were notorious for their poor protection as the tubes would get loose and get easily damaged in shipment.

My guess once people see this posting there will be a run on the GT EL34M tubes as these tubes are sought after, being a very close sonic replica of the original Mullard EL34 XF2 tubes at a far lower cost.

A side note, as these are NOS tubes they do sound harsh and bright until you break them in. You have to give them at least a hundred hours or so before they bloom.