6K6 tubes for 5E3 at living room volume

[Phil]

Hello everyone,

I am interested in trying out the 6K6 tube substituion trick for lower volume ect…Is it really that simple, just replacing the 6V6 pair with a pair of 6K6 or is there more to consider for longer use? Would this work for any other amp with two 6v6 power tubes, like a deluxe reverb?

[stokes]

You will need to rebias for the 6k6's

[Thorny]

Technically - you may have to rebias (the max dissipation wattage on 6K6s is less than 6V6a), but operationally if your amp is not too high of voltage and operates close to what a 5E3 should be a good NOS 6K6s should work fine. Actually, I think that is all there is - NOS.

I have used them this way and customers have too. I say try them.

It is less loud and about half the power - but it is not half as loud!

[Phil]

I would like to try this out the 6K6 substitution on my Misson 5E3 as well as my Delxe reverb clone.

I have always checked and adjusted the bias when replacing power tubes in my DR, always using the books that are avilable for the adjustment values, and this has always work fíne. I cant find any info about the bias requierment for the 6K6?

I havent had my 5E3 longe enough for any tube changes and the catode bias set up doesent make for easy bias adjustments. It seems to be, from reading around, that the cathode bias method is very forgiving, and dosent need much bias adjustment. Just put it the 6K6 and go with it?

Lastly, checking the bias on my DR is no prblem but I have to admit I still don’t know what steps to take to get the bias values on the 5E3. Any one up for a step by step explanation?

[Thorny]

I would say avoid the deluxe reverb because I think the voltages will be too high - above 350v. But a deluxe should be fine. Bruce gave me the idea, I tried it (my amp was based on a 5E3) and so far it works fine. I also tried it on the 5E3x2 - and it seemed fine too.

So my advice is to try it on a your tweed deluxe, but I would be cautious with the deluxe reverb. Bruce might like to chime in because he suggested it and has a lot more experience than me.

[Bruce / Mission Amps]

Stock, I think the Deluxe Reverb has way too high of B+ voltage for a pair of 6K6GTs.
But, if you used a 5Y3GT rectifier, it might come down to an acceptable level.
I'd try biasing a pair of 6K6GTs in a Deluxe Reverb with a 5Y3GT at around 1/2 of the 6K6GT plate rating.

Bruce

[Satamax]

Originally Posted by Bruce / Mission Amps

Stock, I think the Deluxe Reverb has way too high of B+ voltage for a pair of 6K6GTs.
But, if you used a 5Y3GT rectifier, it might come down to an acceptable level.
I'd try biasing a pair of 6K6GTs in a Deluxe Reverb with a 5Y3GT at around 1/2 of the 6K6GT plate rating.

Bruce

I would say it's way too high for 6V6 too I don't know about BF, but the SF i've seen were runing between 390 to 411, that's hot!

[Bruce / Mission Amps]

I've actually seen some come in at +435vdc.
A 6K6GT would have to be biased very low in current for that voltage and then the screens would ignite anyhow since the Deluxe Reverb used a choke and the screen voltage is almost the same as the plate voltage.

Bruce

[PearlyGates59]

I put 6K6GT's in my 5E3, I just took out the old tubes and popped in the new ones. I also put a 15w 8ohm resistor in series with the speaker.
A mod that Bruce posted awhile back.
My Deluxe is not as loud as it used to be....but it's still pretty loud.

Does anybody have a good source for NOS 6k6gt's?

[Henk]

Nice tip using those 6K6GT Tubes.

"I also put a 15w 8ohm resistor in series with the speaker"

There are two wires on a speaker, on what one do you have to put the resistor?

[Bruce / Mission Amps]

Henk, you can remove one of the wires from the speaker, it makes NO difference which one,.... and solder the resistor right on the speaker lug instead and then solder the loose wire back to the other end of the resistor.
Now the speaker voice coil and the resistor are in series.
Half the available speaker energy is across the "dummy load" resistor so the speaker sees half power.
The total power to the speaker with 6K6GTs with this little mod is about 5-7 watts.
Still pretty loud but the 6K6GT tubes sound good and overdrive a little easier then 6V6GTs.