Amp gurus , PT questions and others...

Amp tinkerers and people who aren't afraid of 700 volts or so in here....

Moderators: Slowy, Capt. Black

User avatar
Jay
Vintage Post Junkie
Vintage Post Junkie
Posts: 8224
meble-kuchenne.warszawa.pl
Joined: Sat Sep 25, 2010 9:35 pm
Has liked: 1795 times
Been liked: 1470 times

Re: Amp gurus , PT questions and others...

Post by Jay »

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 :D

User avatar
RectifiedAmps
Fender
Fender
Posts: 565
Joined: Tue Jul 22, 2014 7:05 am
Location: Wellington
Has liked: 243 times
Been liked: 288 times

Re: Amp gurus , PT questions and others...

Post by RectifiedAmps »

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.

User avatar
StrummersOfThunder
Vintage Post Junkie
Vintage Post Junkie
Posts: 8024
Joined: Sun Jul 15, 2012 2:23 pm
Has liked: 1017 times
Been liked: 1615 times

Re: Amp gurus , PT questions and others...

Post by StrummersOfThunder »

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 :D
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 ?

User avatar
StrummersOfThunder
Vintage Post Junkie
Vintage Post Junkie
Posts: 8024
Joined: Sun Jul 15, 2012 2:23 pm
Has liked: 1017 times
Been liked: 1615 times

Re: Amp gurus , PT questions and others...

Post by StrummersOfThunder »

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 in reality I’ll like not do that

User avatar
StrummersOfThunder
Vintage Post Junkie
Vintage Post Junkie
Posts: 8024
Joined: Sun Jul 15, 2012 2:23 pm
Has liked: 1017 times
Been liked: 1615 times

Re: Amp gurus , PT questions and others...

Post by StrummersOfThunder »

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 .

User avatar
Jay
Vintage Post Junkie
Vintage Post Junkie
Posts: 8224
Joined: Sat Sep 25, 2010 9:35 pm
Has liked: 1795 times
Been liked: 1470 times

Re: Amp gurus , PT questions and others...

Post by Jay »

StrummersOfThunder wrote: Mon Oct 07, 2024 2:37 pm
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 :D
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)

User avatar
StrummersOfThunder
Vintage Post Junkie
Vintage Post Junkie
Posts: 8024
Joined: Sun Jul 15, 2012 2:23 pm
Has liked: 1017 times
Been liked: 1615 times

Re: Amp gurus , PT questions and others...

Post by StrummersOfThunder »

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.

Post Reply