KT-66 in a 6L6 amp?

[Low_fidelity2100]

What exactly would be involved in putting KT-66's in an amp that calls for 6L6GC? Obviously a bias would be in order, but other than that, anything else?

This would be in an 83 Fender Concert II (Rivera era amp), if that helps.

 

[the guy who invented fire]

Re: KT-66 in a 6L6 amp?

The bias would need to be changed, the pin out might be different, im not sure about that and then you'd have to make sure KT-66's owudl actually fit the amp...those are pretty big tubes. You'd also want to check the current draw of a pair of 6L6's vs a pair of KT-66's and see if the tranny can handle it or not...

 

[Low_fidelity2100]

Re: KT-66 in a 6L6 amp?

The bias would need to be changed, the pin out might be different, im not sure about that and then you'd have to make sure KT-66's owudl actually fit the amp...those are pretty big tubes. You'd also want to check the current draw of a pair of 6L6's vs a pair of KT-66's and see if the tranny can handle it or not...

K, kool. thanks. I'm fairly possitive that the pin out is the same, but I'll check to make sure.

As far as checking the current draw, how would I go about figureing out whether the tranny can take the extra current draw, if there is any?

 

[the guy who invented fire]

Re: KT-66 in a 6L6 amp?

I think the pinout is the same but I think the KT66 draws a fair bit more current than a 6L6...it might not work, Im not sure what the tranny in that amp can handle. Best advise is to talk to a good amp tech...may I ask why you want to switch ???

 

[Low_fidelity2100]

Re: KT-66 in a 6L6 amp?

I think the pinout is the same but I think the KT66 draws a fair bit more current than a 6L6...it might not work, Im not sure what the tranny in that amp can handle. Best advise is to talk to a good amp tech...may I ask why you want to switch ???

I dunno, just to try it out really.

 

[Gr8Scott]

Re: KT-66 in a 6L6 amp?

Check the specs on your transformer. I think that and the bias are the main two issues. The KT-66's draw more current and will fry a transformer that isn't built to take it. I don't remember if it's heater current or some other spec, but that is the real limiting factor.

 

[ES350]

Re: KT-66 in a 6L6 amp?

KT66---1.27 amps heater current
6L6GC---0.9

pinout is the same...

 

[Low_fidelity2100]

Re: KT-66 in a 6L6 amp?

KT66---1.27 amps heater current
6L6GC---0.9

pinout is the same...

Kool, thanks! Now I just need to figure out where to find specs on the transformers, haha.

 

[ES350]

Re: KT-66 in a 6L6 amp?

with the SS rectifier, the PT is probably something like the 125P7D (ala BF Bassman), with a 3.15 amp filament supply...

 

[Gr8Scott]

Re: KT-66 in a 6L6 amp?

Doing the math for an amp with (3) 12AX7 and (2) KT-66 tube, the PT heater supply should be rated for 3.44 amps at the minimum if not more for a little margin of error. The 12AX7 tubes draw .3 amps each and the KT-66 tubes draw 1.27 each. That's a huge change in the amount of current draw. I've heard that the Chinese KT-66 tubes draw more than normal KT-66 tubes. A 6L6GC equipped amp with (3) 12AX7 tubes would draw 2.7 amps compared to the 3.44 of the KT-66 amp. If the PT is rated at 3.15, I wouldn't touch KT-66 tubes.

 

[Low_fidelity2100]

Re: KT-66 in a 6L6 amp?

Doing the math for an amp with (3) 12AX7 and (2) KT-66 tube, the PT heater supply should be rated for 3.44 amps at the minimum if not more for a little margin of error. The 12AX7 tubes draw .3 amps each and the KT-66 tubes draw 1.27 each. That's a huge change in the amount of current draw. I've heard that the Chinese KT-66 tubes draw more than normal KT-66 tubes. A 6L6GC equipped amp with (3) 12AX7 tubes would draw 2.7 amps compared to the 3.44 of the KT-66 amp. If the PT is rated at 3.15, I wouldn't touch KT-66 tubes.

Yeah after looking around I found that the PT is basically the same as a BF bassman PT. So I guess no KT-66 for me.

 

[Stratman]

Re: KT-66 in a 6L6 amp?

There is an alternative.

Get a transformer just for the heater circuit of the KT-66's

You will have ot get a spacer and have it bolted just below the normal transformer.

A qualified amp tech can do this for you easily, just make sure that you do these itesm...

1) Use at least a 1/2 inch spacer between the bottom of the chassis and the transformer.

2) Wire up only the heater circuit for the KT-66, disconnecting them form the old transformer and using the new transformer.

3) Make sure that all of the bolts are super tight and use loctite

4) Make sure both of your transformers are properly grounded at the same place

5) Make sure that the speakers fit.

So, now the original transformer will not be seeing that power tube heater draw and will operate cooler and the additional (new) transformer will handle the heater circuit only.

IT WORKS

 

[Low_fidelity2100]

Re: KT-66 in a 6L6 amp?

There is an alternative.

Get a transformer just for the heater circuit of the KT-66's

You will have ot get a spacer and have it bolted just below the normal transformer.

A qualified amp tech can do this for you easily, just make sure that you do these itesm...

1) Use at least a 1/2 inch spacer between the bottom of the chassis and the transformer.

2) Wire up only the heater circuit for the KT-66, disconnecting them form the old transformer and using the new transformer.

3) Make sure that all of the bolts are super tight and use loctite

4) Make sure both of your transformers are properly grounded at the same place

5) Make sure that the speakers fit.

So, now the original transformer will not be seeing that power tube heater draw and will operate cooler and the additional (new) transformer will handle the heater circuit only.

IT WORKS

Wow, thats alot of work! haha. Thanks for the advice, but I'm not even sure If I'de like KT-66 in the amp. That'de be alot of work just to find out I didn't dig it.

 

[guitfiddle]

Re: KT-66 in a 6L6 amp?

Howzabout KT66 in a Music Man HD 150?...both transformers in that amp are the size of a baby's head. I don't know what their trannies are rated for, but I know those amps throw 700-750+ volts to the plates when at full tilt. That's enough to kill a 5881 right out of the box.:chairshot

 

[jeremy]

Re: KT-66 in a 6L6 amp?

there are a few new kt66's out there and only one or two are actually kt66's or atleast close. the others are just 6l6 tubes in a cool looking bottle.

i know the new groove tubes kt66 draws about 1.3ma and the old kt66hp does as well but the old kt66c was basically a 6l6. the sovtek kt66 is basically a 6l6 as far as i know