Here is the final form of the amp. Yes, it has a name: The Delta Sonic.
In this video it is me playing at home. With videos of mediocre players like me, great players like Nic Clark, and others you should be able to get a good idea of the amp's character and tone. I plan to take it to the jam my band hosts at Ziggies in Denver this Sunday and let everybody have at it.
The amp has a JJ 5751 preamp tube and JJ 6V6S power tubes. We altered the tone stack slightly since the last iteration.
In this video The tone is on 3 and volume on 5, with the mic volume backed off just a bit. It is very loud for a 15-wall amp. I am using my MXR Carbon Copy delay pedal for just a touch of slap back.
Here is a photo of the delay settings. As you can see, I don't like it too splashy... just a little slap.
rogonzab, I've seen some reviews where people said the tube was prone to microphonics, but I haven't experienced that. There is no way an amp with microphonic tubes would get shipped from any competent custom amp builder. Everything gets tested.
The JJ 5751 sounds good. It is not as warm and full as my favorite, the NOS JAN Philips 5751, but the selling price of that tube has risen to $35. If you wanted an NOS tube in the amp I'm sure Bruce would do it for you but there would be a small price increase for that.
The JJ 5751 sounds like a de-tuned 12AX7, which is pretty much what it is. We tried nine different preamp tubes in four different categories in the Delta Sonic amp: 12AU7, 12AY7, 5751, and 12AX7. The gain factor of the 5751 tubes were what we were looking for, to put the rated power and sweet spot in the right places before the feedback threshold.
This amp fills a gap between the smaller Champ amps and the bigger mid-sized amps with around 30-35 watts. We wanted to retain the fun barkiness of the Champ sound but with a bigger, more dynamic and less compressed tone. And we wanted it to be giggable.
The JJ 5751 did this. Interestingly, I tried a vintage black plate RCA 5751 in the amp and didn't like it much. The JJ is more lively.
So, to answer your direct question, Yes, there are better sounding 5751 tubes but in this particular amp this tube delivered what we were after.
Also, I wanted to comment on my claim that it is "very loud for a 15-watt amp." That is not just hyperbole, it is a fact mostly due to the big iron in the trannies and the high sensitivity of the Eminence Lil Buddy speaker. The speaker is rated at 99.1 dB, while speakers from Jensen and Weber for example are more in the 92-95 dB range. It is a difference you can hear and feel when you play the amp.
This is the only amp I'll be taking to the jam at Ziggies tonight. No excuses. It will be lined out to the PA and I'll have a delay pedal for anybody who wants to use it. Stress test, baby.
I'll get some video and post it later. Hey, if you are in the Denver area come on down. It is a very fun jam.
