I don't remember seeing but which rectifier tube are you using with the 6ar6? I thought I'd try your tube combo in my fire bottle.

They arrived looking like they had been shipped from the factory. Perfect condition, boxes in good shape but aged. Seller claimed they were NOS, so never used except for being tested.

Tested them again and they had like new readings. Popped them in and slowly turned up the volume. Very quiet. Also substituted in a 5Y3GT rectifier for my 274B.

I've played them for 4 hours now. As they may be NOS, I guess I need to break them in. Seems like an odd thing to have to do with tubes which were likely manufactured in the 1940s.

First impression is that they are a bit forward in the midrange, with strings, horns and vocals having a bit of emphasis. At least in my system. The same has always been true of both of my Inspire amps running 6V6s. Maybe this will change as I burn them in. Deep bass was decent & pleasant if not as tight.

Whereas my "big" power tubes: KT66, KT88, KT120, KT150 sound very neutral, open, big soundstage, well defined bass.

I noticed that after playing for 3 hours that my output transformers were only warm to the touch, not nearly as hot as they get with my "big" tubes.

Do you know when/ if Dennis will be taking orders for the phono preamp

Thanks,

Lee

I spoke with Dennis yesterday about this. As before this phono pre is slow rolling. In an effort to lower the noise floor they as moving toward a second chassis for the power supply. It may be a while.

Thank you for the update

Lee

Hey Leew, Dennis and I had a discussion about the phono preamp and I suggested that we separate the power supply from the phono stage.
The phono stage and power supply chassis will be 6"x 9" and should be ready this week.
I'll be posting pics of the layout once I receive them.

Awesome !, I am sure I'm not the only one that has been waiting a few years for it.

Thanks,

Lee

Sorry, I missed your question somehow. I'm using an RCA 5u4g.

And remember how I said I was going to stop tube rolling for a while? That was a lie. lol. I'm using a tall bottle 7n7 and the RCA 5u4g and...

A friend gave me a pair of Mullard El38 tubes and the adapters. I'm in love! Here's the maddening thing about this amp, you can get equally enjoyable, but different, sounds out of this amp. The el38 gives me an amazing amount of clarity and that leads to a depth that its lacking with other tubes. I can especially hear it with acoustic instruments. Piano notes and their overtones ring out more, as do the strings and body of classical guitars. Room reverberations are easier to hear leading to a deepening of the soundstage.

But! The 6ar6 (and the 807 to a lesser extent) gives me a much "thicker" sound. That makes the mid bass and bass hit harder and warms everything up. Rock sounds amazing with that combo and anemic with the el38. Do I really want to switch tubes every time I get in the mood for different kinds of music?

I assume that the el38 is a better load or something for my particular speakers and so has less distortion whereas the 6ar6 has a lot more. I think I still prefer these to the Psvane Kt88 tubes that came with the amp but the el38 is closer to that sound.

The el38 tube is beautiful and the blue glow is super strong! Looking at the specs it seems as though they should last approximately forever in this amp. They are being run far below their max ratings and are practically loafing along. Maybe I should put the 5ar4 back in...

Have I mentioned how fun this amp is?

Thanks for the info. I agree it is a fun amp. I have to admit that I'm also enjoying the heck out of the Western electric 300 b from Dennis. I don't believe I'll be tube rolling much with it though. Yet.

How high a current for the heater?
 

Hey straitwire, do you know how much current the heater circuit can handle in the firebaottle kt88? I'm looking at some tubes that pull 1.5 amps on the heater.