I am puzzled by what you are trying to achieve with the bass channel...
The AA165 has 3 triodes before the PI and full tonestack control between the 1st two triodes with additional shaping on the 3rd.
The 6G6B has 4 triodes before the PI and split tonestack control between the 1st two valves and between the 3rd and 4th triode.
Your amp has only two triodes before the PI.
My simplistic thought is that you cannot achieve with two triodes what Fender did with three and four triodes. I am sure there are smarter people on this forum who can correct me
Yeah, Jay’s right - omitting a gain stage will result in a very different sounding amp. With only 2 preamp stages before the PI the best you can do is emulate the Normal channel of a Deluxe (or similar), but not your original Bassman design.
Jay wrote: ↑Mon Oct 07, 2024 1:55 pm
I am puzzled by what you are trying to achieve with the bass channel...
The AA165 has 3 triodes before the PI and full tonestack control between the 1st two triodes with additional shaping on the 3rd.
The 6G6B has 4 triodes before the PI and split tonestack control between the 1st two valves and between the 3rd and 4th triode.
Your amp has only two triodes before the PI.
My simplistic thought is that you cannot achieve with two triodes what Fender did with three and four triodes. I am sure there are smarter people on this forum who can correct me
I don’t think it’s that outlandish is it ? Brownface sound one Chanel, blackface the other.
There is a completely vacant tube hole there so gain stage adding would seem to be fairly feasible ?
RectifiedAmps wrote: ↑Mon Oct 07, 2024 2:04 pm
Yeah, Jay’s right - omitting a gain stage will result in a very different sounding amp. With only 2 preamp stages before the PI the best you can do is emulate the Normal channel of a Deluxe (or similar), but not your original Bassman design.
Not my design , just a starting point. Given I don’t have enough know how to ‘design’ and the current amp sounds excellent, I will likely just copy it. But it occurred that a good use of the ‘bass channel’ would be to give it a different guitar voice , as I won’t be playing bass through it.
But the over arching thing that I like about this amp is that it’s clean and loud for surf BUT compared to other blackface big iron amps I’ve used it has a really nice compression to it without farting out or getting fizzy.
I suppose this makes sense ? Fairly restrained gain stage , but cathode resistor bias , ss rectifier .
Jay wrote: ↑Mon Oct 07, 2024 1:55 pm
I am puzzled by what you are trying to achieve with the bass channel...
The AA165 has 3 triodes before the PI and full tonestack control between the 1st two triodes with additional shaping on the 3rd.
The 6G6B has 4 triodes before the PI and split tonestack control between the 1st two valves and between the 3rd and 4th triode.
Your amp has only two triodes before the PI.
My simplistic thought is that you cannot achieve with two triodes what Fender did with three and four triodes. I am sure there are smarter people on this forum who can correct me
I don’t think it’s that outlandish is it ? Brownface sound one Chanel, blackface the other.
There is a completely vacant tube hole there so gain stage adding would seem to be fairly feasible ?
That is fair enough, I just assumed you wanted the bass channel operating for a bass guitar.
Yes, you can add the valve in the spare hole, the wiring would be a bit longer between parts, etc but more importantly, it needs to be fitted into the right section of the power supply circuit so that may need changes as well if you want to stick with the voltages as per original design.
So what are you going to do with two copies? (the one you have now and the one you are hoping to build)
To be honest Jay, I’m sure I will just build the one. I literally have all the parts to clone it but I was just playing round with the idea of making something different. I think I’ll just sit with how it is. Kind of hard to work out where this amp came from as it really doesn’t seem to match and kit schematic.
