Dumble modded bassman on ebay

[Reeltarded]

We need this amp. Let's build this amp!

[bepone]

..double post..

[bepone]

It IS super confusing. All the resistors and the early coupler is part of v1 gain thing.

The TS comes after v2. Looks like its here:

09B23DD3-9BE7-4465-B415-35D3894D7175.jpeg

this is clear.. TS after classic CF stage, ala marshall.. but it is stated 2 channels, switchable? where is system for switching if there is no any relays=?
looks like we have LO and HIGH inputs, like JCM800 or Soldano HR, you plug into the first one , you have high gain, you plug into second one, you have classic Marshall JTM..
what is consufing, is that people stating that was possible to use both channels, via some external switching A-B.. and if is that layout, that is not possible? if we plug into normal channel this immediately switches off gain ch..?

[bepone]

We need this amp. Let's build this amp!

i'm just building something, but want right channel (V3) to be classic Fender with one 12AX7 with tone stack, and V1 and V2 to use for high gain, also with separated tone stack, channels will be completely separated between, to give amp more versatillity
V4 will be PI with Marshall values, channels merged before PI

[Reeltarded]

It is only two sides without switching. There are videos of a few amps like this one on youtube. The gain side sounds amazing.

[bepone]

ok, every day i'm closer!
anybody knows what are the values on V2 cathode follower stage?
doesnt seem like 820R and 100k there.. if i put contrast cathode value looks like something about 2k, maybe 2k2
also anode looks like 220k?

[bepone]

some red color is there..220k...? or is a tolerance.. ? impossible to work like that

a3.PNG

[Reeltarded]

hahahaha

6EDA263D-D3AE-4EA4-B2CE-648F44D82436.jpeg

[Reeltarded]

Let's go with normal values there and look at other amps. 820R and 100k.

The first stage is a rat nest of confusion for me. The UP Bandmaster might help.

[bepone]

what colors has this resistor 2 posts upper? black-black-black?

bandmaster UP is low gain version, i dont see any gain there.. real deal is this bassman UP, so first stage V1a, V1b, V2a, V2b makes the amp.
if we go JCM800 values, all is more or less clear. but i dont think this is JCM800 route? or HAD decided last 10-20 years to Marshallise Fenders?
so V2a-b can be like Soldano SLO 220k anode, 100k cathode follower, 1k8-2k2, 1uF in cathode this will be very nice sound, i have installed everywhere, no surprises with that stage, i will start with that values to see.......

[Reeltarded]

I think the tonestack and CF on this amp are same as Bandmaster UP. It's the first stages and placement of the tonestack that make the difference.

Let me find other UP bassman images if I can. If this circuit is worked out I will change plans for a chassis I already made a board for and make it switchable. I love the Sebago interpretation.

The earlier schematic posted in this thread by Aaron Griffin looks very possible.

[bepone]

if you have some other bassman UP post it, i will fire my version today probably

[Reeltarded]

I am jealous.

[bepone]

startup was very succesful, amp is great! in the way that all has great cleans, crunch, overdrive.
in short, fender cleans, marshall drive! this can be easily holy grail? maybe i should open new thread