Don't put SED Winged C 6L6's in your 5150 III

ok so i sent out a few emails yesterday in regard to putting kt66's in the 5150 III, one to fender and one to eurotubes.
The response i got from fender just said "No, do not do this, you will damage the amp. "
and the response I got from eurotubes said "We have not had the chance to run KT66’s in one of these amps but several of our customers have. We’ve received great feedback with them and the thing they where all impressed with was the midrange. KT66’s have a much stronger and more articulate midrange. If you’re looking for a more aggressive and present mid range then they would be ideal.



These amps are adjustable bias and the bias must be set whenever you change the power tubes. This is especially true when switching over to KT66’s as they come in hooter grades then your average 6L6."


So im not really too sure what i should do here. Does Fender just want me to buy their replacement tubes? I sent him another Email asking how the amp may be damaged, so to anyone interested I'll post his response tomorrow assuming i get one.
 
deadweight":t34to7ro said:
ok so i sent out a few emails yesterday in regard to putting kt66's in the 5150 III, one to fender and one to eurotubes.
The response i got from fender just said "No, do not do this, you will damage the amp. "
and the response I got from eurotubes said "We have not had the chance to run KT66’s in one of these amps but several of our customers have. We’ve received great feedback with them and the thing they where all impressed with was the midrange. KT66’s have a much stronger and more articulate midrange. If you’re looking for a more aggressive and present mid range then they would be ideal.



These amps are adjustable bias and the bias must be set whenever you change the power tubes. This is especially true when switching over to KT66’s as they come in hooter grades then your average 6L6."


So im not really too sure what i should do here. Does Fender just want me to buy their replacement tubes? I sent him another Email asking how the amp may be damaged, so to anyone interested I'll post his response tomorrow assuming i get one.
Click to expand...

It would be in Fender's best interest to say something like that. If you have enough adjustment to get the bias right you will be fine.
 
deadweight":vjeu7drm said:
yeah im thinking they are jj's that came in mine they just dont have the red print on them, they have little white stickers on the base that say white 7 on them
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Interesting. Your the first 5150III owner I have come across that had rebranded tubes in it. Everything I've heard so far is that the early models (about the first 500-1000) had a mixture of EH AND Sovtek pres w/ Sovtek powers. Models after this had branded JJ's. Did you buy your amp new? If so, what is the serial number?
Also, you may want to try the EH and Sovtek mix that came on the early models. I think the amp sounds much fuller and smoother with less fizz on the high end compared to the JJ's.
 
Well I'm not at home right now so I can't give you a serial number but it's brand spanking new, I ordered it through a local website which was out of stock so I had to wait nearly 2 months for the amp to make its way from fender through long and mcquade and to me. So it was still in the box and everything, maybe this is their new approach. All of the preamps were JJ ecc83's. I've just read that KT66's can really fatten up the sound which I would love, so after a few more emails I'll give it a shot assuming I think my amp will be safe.
 
really curious about the results of different tubes (KT66 etc..),

I recentely got a 5150 iii serial number 600 , with the mix of sovteks/eh , sounded pretty decent off the bat,

I since changed a few things around to

a 5751 in V1 , and JJs in v2,v3,v5,v6, keeping the sovtek WC in v4,

The biggest thing however was adding an EQ in the loop, really helped the most in bringing down the brightness and bringing up the mids, fattening it up, and in the process giving me a master volume

I might try the stock pres again to compare sound, i tried so many different combinations at this point it would be 'typical' that the stock pres sounded the best after all

//

i did have a question about bias, have you found warmer bias settings result in a warmer/less fizzy amp or ?

I've changed the bias on amps with test points, but how is it accomplished on the 5150 iii ?
where is this bias adjust trimpot?

(here's a picture of the guts of the amp if it helps:
http://www.themusicfarm.com/images/prod ... ry.401.jpg
)

I'll keep searching threads in the meanwhile =)

thanks for your help
 
i think it's what i initially thought, it's the blue trim pot that can be seen near the top right,

I bought mine used and the mounting bracket is somewhat bent, doesn't affect the amp but i have to undo the transformer mounting bracket to remove the amp out of the chassis =(( which sucks

now just wondering how you found warmer bias settings =0
 
So I sent this to fender last night :
Hello Ed, I was wondering, would this still damage the amp if the kt66's were biased up properly or how it might damage it, I only ask because the staff at Eurotubes have told me that they've had customers do so with good feedback on this. I'm in no way trying to say anybody knows your guys' amp better than you or insult you in any way but rather just looking for a few different tonal options for my amp. Don't mean to piss you off or waste your time. Thanks again in advance

And got this in return :
The plate voltage will be too high, and we do not give out that info, this is not what the amp is designed to use.

So I'm gonna relay this back to the guys at Eurotubes and see what they have to say about it because I thought the kt66 was sort of a drop in replacement for a 6L6.
 
I felt that around 36 ma the clean channel seemed to warm up a bit but that could be in my head. And I've been switching the power tubes every time I rebias so it doesn't really mean much. Yes that blue trim pot is the bias adjust and there are two contacts under the power tubes labelled bias - and +. You'll just have to experiment I guess
 
I would think if it falls within range/spec and is biased correctly it would be fine,

until you find someone who's actually done it with success I think you'll be relaying a lot of emails back and forth as they both differ in opinion
 
with regards to the warmer bias did you find it only really affect the clean channel then or?

I'll certainly have to experiment, I'll see if i can get the damn thing out of the amp head cabinet, due to the bent transformer bracket , the transformer gets stuck on the wooden blocks to hold the grill in =( no fun, pulling out the transformer isn't my idea of a nice way to spend the evening =)

for now the clean channel seems fine, certainly not as chimey as other amps but very nice
 
deadweight":xckp5sjp said:
And got this in return :
The plate voltage will be too high, and we do not give out that info, this is not what the amp is designed to use.

So I'm gonna relay this back to the guys at Eurotubes and see what they have to say about it because I thought the kt66 was sort of a drop in replacement for a 6L6.
Click to expand...

The plate voltage of the amp is around 480. JJ KT66 can handle up to 550. :confused:
On the other side, will they fit in?
 
aftec":3vr1qv1y said:
deadweight":3vr1qv1y said:
And got this in return :
The plate voltage will be too high, and we do not give out that info, this is not what the amp is designed to use.

So I'm gonna relay this back to the guys at Eurotubes and see what they have to say about it because I thought the kt66 was sort of a drop in replacement for a 6L6.
Click to expand...

The plate voltage of the amp is around 480. JJ KT66 can handle up to 550. :confused:
On the other side, will they fit in?
Click to expand...

Yeah I don't know, the guy seems like a bit of an ass. We don't give out that info?. They should fit I think but you have to remove the metal tube stabilizers because they apparently ground out the metal base which will cause a malfunction. I'm waiting on one more reply from eurotubes.
 
I sent that email from fender to eurotubes and just got this back :
Very interesting!! We’ve used the JJ KT66’s in applications well over 500VDC on the plates with great success. At 485VDC you’d be just fine.

 

Saying that the amp was designed strictly for 6L6’s is probably quite true. However, the KT66 is like the Brit version of a 6L6 and the specs are so close they’re pretty much thought of as interchangeable in most applications.

 

At any rate, if you put the KT66s in the amp and had a component fail down the road, Fender would tell you without a shadow of a doubt that it was related to the KT66’s. Even though they operate with virtually identical specs. If the amp is still under warranty this is something to consider. Heck, if you even take the back panel off the amp they’ll void your warranty…

 

Fun stuff huh!!

So I think I'll probably give it a shot, with my luck it'll probably sound like shit after all of this trouble.
 
yeah i think i'll do that and bend the bracket back , I'm going to set it up tonight at home , and bring it to work tomorrow (i work at a venue with some pretty knowledgeable techs so they can help me out)

hope those kt66s work out, i think it could be the missing link in the amp, i'm not a fan of having to put an eq in the loop but if it sounds good then that's what you gotta do
 
just thought i'd add, i decided to put the original preamp tubes back in to see and i'm back to using the stock configuration of sovtek 12ax7wc in v1+v4, EH 12ax7s in the rest with sovtek LPS in v7+v8,

i tried tung sols/jjs/sovteks and a 5751 in various combinations V1 to v6 only to come back to the sovtek/EH mix that the amp came with, the clean isn't quite as chimey but channels 2+3 sound creamier with less fizz than any of the other combos i used, and now i can finally get some sleep =0
 
nevusofota":174n60hv said:
deadweight":174n60hv said:
yeah im thinking they are jj's that came in mine they just dont have the red print on them, they have little white stickers on the base that say white 7 on them
Click to expand...
Interesting. Your the first 5150III owner I have come across that had rebranded tubes in it. Everything I've heard so far is that the early models (about the first 500-1000) had a mixture of EH AND Sovtek pres w/ Sovtek powers. Models after this had branded JJ's. Did you buy your amp new? If so, what is the serial number?
Also, you may want to try the EH and Sovtek mix that came on the early models. I think the amp sounds much fuller and smoother with less fizz on the high end compared to the JJ's.
Click to expand...

Oh and the serial number is 4998 by the way
 
university81":3msg60cd said:
just thought i'd add, i decided to put the original preamp tubes back in to see and i'm back to using the stock configuration of sovtek 12ax7wc in v1+v4, EH 12ax7s in the rest with sovtek LPS in v7+v8,

i tried tung sols/jjs/sovteks and a 5751 in various combinations V1 to v6 only to come back to the sovtek/EH mix that the amp came with, the clean isn't quite as chimey but channels 2+3 sound creamier with less fizz than any of the other combos i used, and now i can finally get some sleep =0
Click to expand...
I have found the same thing. I have tried different preamp tube combos and nothing has beat the original set up of EH and Sovteks. I was always very happy with the sound of the amp but I just wanted to experiment. When I go to GC I'll occasionally plug into a late model EVH head to see if it sounds any different than mine and I keep noticing that there is too much sizzle in the high end and the mids aren't as cutting, especially on channel two. I relate it to the JJ's. I also feel the JJ's may be responsible for those people out there that do not like channel two. For me, channel two is where the amp shines.
 
deadweight":32uy7ax3 said:
nevusofota":32uy7ax3 said:
deadweight":32uy7ax3 said:
yeah im thinking they are jj's that came in mine they just dont have the red print on them, they have little white stickers on the base that say white 7 on them
Click to expand...
Interesting. Your the first 5150III owner I have come across that had rebranded tubes in it. Everything I've heard so far is that the early models (about the first 500-1000) had a mixture of EH AND Sovtek pres w/ Sovtek powers. Models after this had branded JJ's. Did you buy your amp new? If so, what is the serial number?
Also, you may want to try the EH and Sovtek mix that came on the early models. I think the amp sounds much fuller and smoother with less fizz on the high end compared to the JJ's.
Click to expand...

Oh and the serial number is 4998 by the way
Click to expand...
Hmmm. So you have a very late model. I wonder what brand these tubes actually are now.

My serial number is 460.
 
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