Bombacaototal wrote: ↑Fri Apr 30, 2021 10:00 am
Hi all, I spotted a couple more mistakes. The cathode cap on the mixer circuit is reversed on Ryans layout. It should be 1uF on the dry path and 5uF on the wet. This is as per Jap schematic and in line with all other SSS amps which always have a fatter/more low end on the reverb side
Second is the LNFB on the reverb driver, the 2.2M should come before the 10K, like other SSS amps and as per Jap Schematic
Both will yied in sonic differences
If I'm reading correctly, the "fix" would be like this? I feel like this was debated once before..
Screen Shot 2021-04-30 at 6.18.53 AM.png
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Bombacaototal wrote: ↑Fri Apr 30, 2021 10:00 am
Hi all, I spotted a couple more mistakes. The cathode cap on the mixer circuit is reversed on Ryans layout. It should be 1uF on the dry path and 5uF on the wet. This is as per Jap schematic and in line with all other SSS amps which always have a fatter/more low end on the reverb side
Second is the LNFB on the reverb driver, the 2.2M should come before the 10K, like other SSS amps and as per Jap Schematic
Both will yied in sonic differences
If I'm reading correctly, the "fix" would be like this? I feel like this was debated once before.. Screen Shot 2021-04-30 at 6.18.53 AM.png
found a mistake on the power supply as well. According to the Jap schematic, the 60uF is on the PI supply and not on the screens...now if the jap schematic is not correct on this is another story, but thought i would bring up for discussion, but this will definately change the feel of the PI
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By analysing the gutshot of 002 and comparing with the trace of 001, the 2.2M could be either way, maybe soldered after 10K or at the input signal lug.
The opposite side of the 2.2M is soldered to the 0.05uF directly, I think, without a board lug, and the 0.05uF is epoxed to "glue" in the board. The other side of the 0.05uF must be jumpered straight to the socket PIN1.
So I guess the question remains if the Jap schematic is reliable on this....
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Last edited by Bombacaototal on Fri Apr 30, 2021 11:54 am, edited 1 time in total.
Rafael, all the "mistakes" you pointed out have been discussed, wet /dry mixer: you want more bass on dry side, making more bass on the wet side is making the reverb boomy. That's why there is 5uF cathode bypass cap on the dry side.
Screens/pi filtering: 60uF for transient spikes on the screens and it feeds another node which make more sense to put the 60uF, or 47uF in my case, on that spot.
Bombacaototal wrote: ↑Thu Apr 29, 2021 10:27 am
Hi all, I was double checking the 002, as I am planning on doing it, and I think there is a mistake on the filters.
PLease find a "rough" correction (in pink - with erased in black) on the layout and the trace from 001. At least this is my perception...I think the current one is as per Jap Schematic, which looks wrong if you check the other SSS references...
On the 001 board you drew some black lines suggesting where the tracks would be. I guess it could be wired like this, but it leaves me wondering what that bare bridge wire is for.
Bombacaototal wrote: ↑Thu Apr 29, 2021 10:27 am
Hi all, I was double checking the 002, as I am planning on doing it, and I think there is a mistake on the filters.
PLease find a "rough" correction (in pink - with erased in black) on the layout and the trace from 001. At least this is my perception...I think the current one is as per Jap Schematic, which looks wrong if you check the other SSS references...
On the 001 board you drew some black lines suggesting where the tracks would be. I guess it could be wired like this, but it leaves me wondering what that bare bridge wire is for.
Hi Richard, the 001 board is full of bare bridge wires like this, I think where he started and where he finished were somewhat different. On that case of the filter circuit, who knows, could well be due to the size of the component, it would be fairly snug to fit on the very close together lugs, but still feasible...
Although i am intregued, and would like to know what the difference in sound would be, i don't see the same thing you do. That is, on the 001 board. On the gutshot of the 002 i realy can't see anything.
But what I see on the 001 is this:
There is a bare wire going from the white wire to the 0.001 cap. I believe this is a repair. The reason for my assumption is that: 1, I think i also see a trace under this wire; 2, there is a blob of solder on the eyelet that does not seem like the work of Mr. Dumble; 3, there is something what looks like green oxidation on the eyelet, which could explain why the repair was needed.
On the other side of the 0.001 cap i can see a trace going to the bare bridge wire. This wire goes towards the bigger cap. Since this side of the bigger cap connects to the anode of v1b, i believe both caps in the ss001 are parallel and not in series.
This bare wire could not have been for the 470k resistor imo because however the caps are wired, in both cases the 470k should be over the wires going to the filterswitches.
( Now i do think initialy Mr. Dumble planned for some component in that spot, in series with the 0.001 cap, but changed his mind later)
So to mee, at least on the sss001, the caps look to be in parallel.
Now on the sss002 i couldn't tell. The picture is to blurry for me to see anything. The way both caps are placed on the board would suggest you could very well be right. Looking at this board, it sure would be logical if they where in series.
On my amp I changed the 0.001 cap from parallel to in series with the 0.01 cap. (the ones that go to the step filters)
Filter settings seem to be more active, not a night and day difference but noticable. With a certain settings I can get closer to that SRV's "Riviera Paradise"/"Lenny" sound which is very cool !
Also the reverb trail seems to be a litlle bit louder. I might revert the reverb nfb from 180k to 100k.
I'm a bit behind revising my #002 but I made the following changes yesterday and tested it this morning. I should be up to date now.
1) V1 LNFB is now 100k from 1m
2) Entrance to filters is .01uf first and then the .001 network
3) Reverb nfb changed to 100k vs 270k as written on the Japanese Schematic.
4) 60uf screens filter vs 20uf originally
5) Richard's reverse polarity protection diofe
All I can say is that I liked the amp before, and now I LOVE this amp! It's incredible what these changes did. The amp is not "bright" or lacking bass at all. I actually find myself using the bass filter more now. I agree with Erwin that the high filter is much more subtle throughout the range. The touch sensitivity and compression is perfect. Before, it was pretty wild amp that needed to be pushed hardddd to get the power tubes working and for the amp to sound good (I use a Boss TAE reactive load so it wouldn't blow my ears off) Driving it hard made the nice natural compression too by driven tubes but now with the lnfb it is so much easier and intuitive to play. Reverb sits perfect too in the mix with the 100k.
I took before videos so I can compare with after the changes. I'll post it here when I'm done. Attaching pics of the changes. The amp reminds me a lot of my JM sig I built.
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I had a feeling my modded JM sig wouldn't be a million miles away hence me not jumping on to this build, tempting as it was/is
M
but you're missing the controversial filters
I just checked my recordings and I only properly captured the after properly and I must not have selected the proper input device for before I was too excited. I'll still post the video for tests
!
I had a feeling my modded JM sig wouldn't be a million miles away hence me not jumping on to this build, tempting as it was/is 
I was too excited. I'll still post the video for tests