So what's wrong with Fender Groove tubes?

[igorBG]

Correct me if I am wrong. Fender makes and sells Groove Tubes (ordinary and "made in USA" models) and their tube amps come with these stock, right?
The first thing that everyone suggest to do is to swap stock tubes with JJ, EX, RCA, Svetlana etc.
Are Groove Tubes tubes so bad?
Or maybe, stock amp tubes differs from Groove Tubes that they sell separatelly?
I'm confused

[Axis29]

Fender don't make no tubes... From what I understand, Groove Tubes doesn't make them either. They take other brand tubes, tests them for certain values and conditions, group them together into pairs, quads, whatever and then rebrand them as GT tubes.

So, I'm guessing they add the Fender logo to a certain amount of them and Fender buys them at a bulk rate. Fender installs them in their amps and GT makes a tidy profit. Fender gets a halfway decent tube that's halfway consistent for a reasonable production cost... then they warrant them for a short period of time once you've turned them on. GT improves their market share, Fender brags about using GT tubes....

GT tubes and EH tubes may be the best tube in the world... though my personal experience showed that old RCA's and JJ's were more musical and had characteristics I liked when they were installed in my amp.

Being a guitarist, I spend way too much time obsessing about my tone and trying to buy my way into it... as opposed to what I should be doing more of, and that's playing my way into it...



Seriously, I found the GT and EH tubes that were in my amp 'tight' and unexciting compared to the replacements I put in there.

I have heard reports, but have no experience with the EH tubes failing and taking internal amp components with them. I'd rather not take that chance myself... besides although I loved the way my amp sounded when I bought it, it sounds even better now!

Lance bought an amp off eBay the other day and brought it over. It had EH power tubes and we though one of them was rattling. I had a pair of JJ 6v6's as backups and we put them in the newsed amp. It didn't solve the rattle, but it sure made that amp instantly more musical! We never got the rattle solved, but we definitely made a decision about JJ v EH power tubes!

So, Gt tubes may work for somebody, but with a small investment, I found vast improvement and I'm spending even more time playing.. instead of obsessing

[mr_hankey]

I think it has more to do with price than anything else. GT tubes sometimes cost several times more than other tubes of comparable quality.

[Guitar_Ninja]

The Fender branded Groove Tubes are of a lower quality than the ones you can buy aftermarket from GT. The aftermarket ones are supposedly quite good and many people like them.

But since many online tube shops do the same testing as Groove Tubes for matching, microphonics, etc. I can't really think of a reason why you'd buy rebranded tubes from them for an inflated cost when you can just buy specific brands direct from other sources and get the same testing but know what said brand actually is. And for cheaper. YMMV.

[Jim L]

Originally Posted by mr_hankey

I think it has more to do with price than anything else. GT tubes sometimes cost several times more than other tubes of comparable quality.

I've found that the GT label increases price, but not necessarily quality.

Axis29 hit it on the head... GT is simply rebranding tubes after testing and matching other manufacturers' tubes. Find a reliable source and you can get high quality tubes without paying more for the rebranding effort.

[mikespe]

If I may hijack this thread...I have a Fender VibroChamp XD that I love the stock tubes...however since it is my first tube amp I have nothing to judge it by. Where a place to get tubes a an inexpensive price. Every forum I go to they all rave about the JJ's. I am assuming the stock tubes in my amp are the GT's mentioned above. But I wouldn't mind comparing to other tubes.

Thanks

[Jim L]

Originally Posted by mikespe

If I may hijack this thread...I have a Fender VibroChamp XD that I love the stock tubes...however since it is my first tube amp I have nothing to judge it by. Where a place to get tubes a an inexpensive price. Every forum I go to they all rave about the JJ's. I am assuming the stock tubes in my amp are the GT's mentioned above. But I wouldn't mind comparing to other tubes.

Thanks

Yeah, go for it! I have a single 6v6 Silvertone (think Champ) and it's a cheap and easy way to try different makes of tubes. Actually, the preamp tube was the one I found the most interesting, due to the huge difference in gain between different types of preamp tubes.

[JimiBryant]

well.. stock tubes are a place where companies can cut costs.

premium quality tubes generally provide good sound and long life

so-so tubes can provide good sound & shorter life or not-so-good sound.

poor quality tubes can short out and potentially damage an amp.

I would tend to agree the Fender-supplied Groove Tubes are not as
tightly graded as after-market Groove Tubes but I wouldn't dismiss
GT's entirely, either.

JJ's are really good "modern" tubes - but any supplier who screens
out bad tubes and matches power tubes is going to be able to provide
the best selection as well as advice as to what's best for the money.

Lord Valve, Eurotubes, and KCA are all reputable suppliers..

[Robin Nahum]

I thought the problem was largely with their 6V6s, which are rebadged EHs, and have been found to be unreliable in DRs where they need to handle more power.

[Doug Ferguson]

When I bought my BJ a couple of weeks ago, I asked the sales guy if his store (I'll name no names) sold tubes. Yes, he said, Fender tubes. I asked if those weren't just rebranded Sovtek's, but he said, oh no, they're Fender. I pulled one of the preamp tubes and showed him that is was indeed a Sovtek tube, as were the other preamp tubes and the EL84's. I swapped the stock one's for Tung Sol's an JJ's, which really do fill out the tones. But the stock tubes are fine as backups. Anyway, I hope my sales guy remembers what I showed him, so he'll be a little more knowledgable about some of his products.

[markw51]

Originally Posted by igorBG

Correct me if I am wrong. Fender makes and sells Groove Tubes (ordinary and "made in USA" models) and their tube amps come with these stock, right?

To my knowledge audio vacuum tubes have not been made in the U-S for years. They're all made in Russia and Asia now. NOS (new old stock) American and European vacuum tubes are very expensive and becoming more so.

[mad dog]

The Groove Tube 6L6s that came stock in my used '57 RI Tweed Twin are rather nice. Never having thought much of the brand, it's a pleasure to find some I like. JJs are my usual choice for newer 6L6s.

[marshman]

Axis29 has it about right. Groove Tubes buys tubes in bulk from manufacturers abroad. They then test the tubes for a variety of factors and group and match them accordingly. Some Groove tubes are then sold to Fender as OEM for their amplifiers.

Groove Tubes did, a few years ago, manage to acquire a large stash of materials from a former GE manufacturing facility, which they used to manufacture tubes abroad to old GE specs. They were reasonably well received, in general, but most found they could get original versions for about the same as GTs replicas, and did. http://www.groovetubes.com/GT-6L6GE_Quartet_P1714.cfm

Electro-Harmonix (as part of Mike Matthews empire, occasionally referred to as New Sensor, probably the original part) is much closer to a 'manufacturer', as they actually OWN a tube-manufacturing plant somewhere in what is now Russia. They engineer, manufacture and distribute tubes "in house" and sell them to anyone interested. As a case in point, I had tubes in my Fender HRDx that had a sovtek label under a GT label with a Fender label on the other side.

People wil argue about the sound/tone of tubes until late in the night, and it's roughly akin to arguing abut ice cream flavors--there's no reason for me to have to like what you like.

FYI--New Sensor manufactures tubes under a variety of names--they have acquired several trade names and use them to sell tubes. Sov-Tek, Electro Harmonix, Mullard, GEC/Gold Lion, Tung-Sol and Svetlana tubes are all made in the same Russian factory. Not sure how they wrenched the Svetlana name from the actual Svetlana company, but they did, and that company now sells it's tubes with the 'winged-C' (=C=) logo.

[gpower]

Originally Posted by mikespe

If I may hijack this thread...I have a Fender VibroChamp XD that I love the stock tubes...however since it is my first tube amp I have nothing to judge it by. Where a place to get tubes a an inexpensive price. Every forum I go to they all rave about the JJ's. I am assuming the stock tubes in my amp are the GT's mentioned above. But I wouldn't mind comparing to other tubes.

Thanks

I really like dealing with Bob at eurotubes.com

[surfoverb]

I've got GT labeled sovteks and they're fine.

[Murphy Slaw]

I've never had a problem with Groove Tubes. Or Fender tubes. Or Mesa Tubes.

I've been lucky.

(knock on wood)

Murph.

[backalleyblues]

Have had Fender-branded GT's in my HRDX as well, lasted 3 years, 200 gigs, and a number of recording sessions. Finally replaced the power tubes back in January, after feeling the amp sounded "tired". GT 6L6, rated 5, perked the amp back up after rebiasing. Have held up quite well, though at the pace we're gigging, might have to replace these tubes i couple months :D

Would love to get JJ's in this puppy, but other than mail-order, nobody carries them except a guitar shop that appeals to snobs with too much money, and overcharges for the privledge. I'm not crazy about mail-order tubes, mainly because of what I have seen UPS and FedEx do to the packages at times (football, anyone?). how many people here have had a package destroyed by a shipper, and how well do tubes sent mail order usually arrive? My reasons for not trying something that's not avaiable at GC or Sam Ash...

Franc Robert
Back Alley Blues Band

[surfoverb]

Originally Posted by backalleyblues

I'm not crazy about mail-order tubes, mainly because of what I have seen UPS and FedEx do to the packages at times (football, anyone?). how many people here have had a package destroyed by a shipper, and how well do tubes sent mail order usually arrive?

I wouldn't let that stop me. I've never had any package damaged. The tubes they sell at guitar center arrived to them via the mail too.(or at least a truck)

[Doug Ferguson]

Originally Posted by surfoverb

I wouldn't let that stop me. I've never had any package damaged. The tubes they sell at guitar center arrived to them via the mail too.(or at least a truck)

+1. Never had a bit of trouble with the tubes I've had shipped to me. They're always well packed and protected.

[Dacious]

For most small wattage amps, you can run whatever tube is specified. For a 2-tube amp it is worth buying in matched pairs, mainly so you know someone has fired the tube up in a tester and verified it's current draw.

Groove Tubes at least are a a consistent supplier - if you always buy the same rating, you'll get consistent service. You will pay them for this service, but for many people it is cheap insurance. Unfortunately many of the modern manufacture tubes are made (like whitebox Sovteks) to provide the cheapest OEM tube that will live in a new amp. The premium 'branded' tubes are usually better tonewise, but the QC is perhaps not as thorough as it used to be.

The biggest problem with new-production tubes is inconsistency. You might put them in your amp and find it draws a lot more current than NOS or the original tubes. So if you don't measure current draw it might draw more current and produce more power and therefore heat than the tube is designed for. Not that this doesn't necessarily mean you can see or hear this, but the tube life might be short and it may overwork other components, like the power tranny with current draw and the output section by increasing gain.

People like Eurotubes at least vet the tubes for this, by testing them to see they won't exceed current draw in a typical fixed bias amp the tubes are likely to see. Lord Valve and Triode Electonics are some others, but there are plenty more. if you overheat the grids by pulling too much current it's not good!

If you have a single-ended amp like a Valve Junior, you're pretty safe because cathode-biasing will mostly prevent a tube eating itself and the amp. Some later Champs need the best tube you can buy becaue they buzz them hard. JJs are good for these and Deluxe Reverbs because they are very tough, and not bad for tone. EHs would be fine in a lower-voltage amp like a 5E3, but again I'd go for matched ones. There were good and bad NOS tubes - but they are typically much better made and more consistent on test, and produce consistent output.

In a Laney or Vox AC-type amp and to a lesser degree Blues or Pro Junior you need to be careful because these amps push the tubes harder than the tube was specced for. Matched tubes of moderate current draw would be good in these.

The WXT+ tubes I have in my VR pulled dissipation up to 38-40ma measured at the plates, which is about as much as you really want at 445 plate volts. They're a bit crunchy up there, but I like that.

[6x47]

"38-40ma measured at the plates"!

Just curious, how do YOU measure current at the plates?

[igorBG]

Oh, got it now, thanks

[sjhusting]

Originally Posted by 6x47

"38-40ma measured at the plates"!

Just curious, how do YOU measure current at the plates?

Well, I don't know how Dacious does it, but I do it like this:

For fixed bias amps, I measure the total current with a bias adapter, which is just a tube socket fitted on a tube base, with a 1 ohm, 1% resistor in the cathode path, and test leads hanging out the side. I=V/R, since R=1, # amps = #volts.
But then you have to deduct the screen current, so measure voltage drop over the screen resistor, use ohms law; done. You have to actually measure the value of the screen resistor, not just use the nominal value.

For cathode bias it's just the same, except I don't use the adapter, just measure straight over the cathode R.

Some amps have a 1ohm resistor built in, so you just measure over that instead.

That's all there is to it.

To calculate plate dissipation, you have to measure a few more things.

steven