new KT77 and GZ34 tubes in Roadster

[talltxguy]

Heard a lot about the KT77's and finally got a chance to try them out. I ordered them from The Tube Depot with a bias point of 50. I only ordered a pair of them in case I didn't dig things.

I only used spongy as bold would be way too hot - most likely destructive - with a rating of 50.

I tried all the channels with diodes going and thought the distortion played nicer and smoother than EL34's or E34L's that I've tried. The cleans were very nice - with good bass and some crispness as well.

I then tried the KT77's with the stock Mesa rectifier tubes and didn't care for the distortion tones at all although the cleans were descent.

Then I switched rectifier tubes to GZ34's and found the magic. I don't see the need for diodes at this point.

Interestingly enough, the 50 watt mode sounded better with the KT77's than the 100 watt mode with my other tubes going on. I shall be ordering another pair at payday. 8)

Bias switch set on EL34:
1) Spongy diode drew 54.2 mA.
2) Spongy with JJ GZ34's drew 46.9 mA.
3) Spongy with stock Mesa rectifier tubes drew 39.8 mA.

 

[espboogie123]

I wanted to try out the gz34s in my roadster but for some reason I read alot that roadsters trip out with gz34s. Many started to blow fuses. The dual and triple recs have no problems running the gz34s.

 

[talltxguy]

I was concerned about it too. I read a bunch of posts on here from guys using GZ34's with their Roadsters. Now I'm one of those guys.

Don't know if it matters, but I always run my amp in spongy.

 

[LithiumZero]

I run GZ34's in my Roadster in bold and have zero problems. I really like them too.

 

[glassjaw7]

Cool! I love my 77's and GZ34's in my rectifier. Awesome improvement. 8)

 

[TheSoulsRemain]

For having some 6L6 (JJ , TungSol), KT77, EL34 and GZ34, best Improvement is to setup the BIAS at his correct value.
But swapping 5U4 for GZ34 is the Best starting point to put a BIAS pot in DR. (because If You have crossed the line to find an improvement by using a non-Mesa tube, it means that the second step is a BIAS pot.)

 

[talltxguy]

Right now I'm running the KT77's at 70% max plate dissipation with the spongy tube rectifier (GZ34) mode. It's a good bias and sounds really good. I do check my bias with a meter even though I buy tubes with specific bias points on them. When my warranty runs out, I will most definitely get an adjustable bias so that I don't have to worry about ordering tubes with an exact bias point to achieve 70%.