My take on Eric Johnson's Steel String Singer #005

[Stratoblaster]

Since Ive already had a prototype happening it wasn't much for me to mess with filter & reverb mixing section.

I tried the circuit you so kindly provided beasley and I can report it works perfectly.

I tried changing & omitting various components and it was for the worse. It works best as is.
For example I added the 1meg/33pf network. For my taste the dry signal became too low and reverb is overpowering on anything over 2 on the send and return pot.

[beasleybodyshop]

That's awesome! I never got a chance to build this one out yet. Maybe someday!!

[Bombacaototal]

Hi guys, first time posting here.

I was working on SSS#005 from AN pictures also, I was perplexed by 1Meg resistor feeding filter circuit, I was also perplexed by wet/dry mixing. These are results of my work. Please note, I have never heard or saw real SSS, AN or Bludotone copy of SSS and most importantly I have not built an amp based on my layout/schematic yet, so assume it has errors.

I would like to take this opportunity to thank all of you guys who contributed to this and many other forums, you guys literally changed my life.

Great job, very detailed layout.

Just a few corrections, tonestack grids are indeed 22K on input and after the volume is 220K without a cap (pics attached - these are correct on your layout).

On the PI it is 150K and 330K.

As far as bias pot, I have seen 10K pot with 100K to ground (attached) and 50K pot with 68K to ground (like your layout).

On the bias board, between the 2 caps, I am not sure if it is 1.5K or 15K. The resistor in between the diodes, I've seen 27K and 15K (pic attached)

On the dropping resistors, I've seen both 150K (attached) and 220K to ground to emulate the FET

Send is 1M and presence is 25KL, reverb return is 250K (pic attached)

[Bombacaototal]

just a couple more, the PI sometimes has 470R instead of 500R, and the reverb driver has the bypass capacitor

On the bias board I've seen a pair 22uF as well (attached)

Cap in the entrance of PI confirmed as 22n (attached)

[rootz]

Never thanked you for the detailed pictures, thank you!

I took the gamble and build me a demo #005 based on the schematics here, the layout, some LTSpice sims. There are still some blanks to fill in.

1) Where does the resistor string on the can cap connect to the PSU board? I some pictures it is obvious that there are two wires connected to the second 22uF cap on the PSU board. Would or could that mean that the CF positive supply is coming from the last 22uF cap on the PSU board (closest to the pots)? The black and white picture where you can also see the pot values, indicates that there is a separate node available. You can see two power resistors next to each other. Could also mean the can cap string and CF positive come from the second 22u cap and the PI from the third. That seems less logical, as that means you cannot independently adjust the positive voltage for the CF. The latter makes much sense to me in a 150W amp with probably around 500V on the plates. I see different values of resistors last in the string on the PSU board. On one board it looks like 47k (!). The resistors are Vishay PR03's. On those red is almost the same colour as the resistor. Not clearly visible. Brown is darker, by a fair bit. Orange? Not sure, haven't got any. I went with 470r, but that value in hindsight just does not make sense to me. On another board I.m pretty sure I see a blue 10k MOX resistor. On yet another PSU I see light MOX resistors with the value printed on them
2)The value of the bypass cap on v1b is an educated guess. In its current form, my amp surely does not need more low end. It could do with less!
3) I now have a A500k bass pot and A250k mid pot. This seems to give to much low end.
4) I settled on 68k grid stopper for v2b. It shows as unknown in schematics and layout. 220k would work too, maybe making the amp a bit friendlier to tele's.

While the amp sounds pretty good as is, quite addictive as a matter of fact, it is very bass heavy and scooped. No idea ow the real 005 sounds, or all its clones. Are those scooped and/or bass heavy? Not much drive in the amp as is as well. That could be caused by the fact that I do not use caps on the cathodes of V2 and the reverb driver. The mix of the reverb and dry signal is really nice though, especially a bit lower on the filter settings.

So, some blanks to fill in. Help with filling them in is very welcome.

[talbany]

No idea how the real 005 sounds

I am pretty sure the last song he plays (55:27) is the SSS. You can hear him shift between the SSS and ODS on the song ZAP! (Not the best recording)


Tony

[rootz]

Thanks Tony. Not the best recording indeed. But can we assume that the low end of the camera clips so severely because the amp has got a lot of low end? Yes, reasoning like that means cutting corners a bit. We have no idea what quality the recording device was.

Anyway, I was looking at a close up of the filters. On the low filter you can see all values but one. Would you (anyone whom it might interest) agree that the partly obscured resistor does not look like a 390k? What does it look like to you? The resistor is circled in red.

[rootz]

Also in line with my earlier questions/blanks to fill in:
What are the values of the resistors circled in yellow?
The PR03 (brown MOX) looks like yellow violet orange to me. But it is difficult to see exactly as lighting influences vibrancy and appearance of colours. What do you think?

Also for the blue MOX resistor: that is most definitely not a 470 Ohm resistor, right? Looks more like 10k to me. Agree/disagree?

[talbany]

Thanks Tony. Not the best recording indeed. But can we assume that the low end of the camera clips so severely because the amp has got a lot of low end? Yes,

When I saw Eric shortly after Ah Via Musicom he was using #005 along with his Tube Screamer so the low end was not as punchy and was used primarily as his dirty rhythm tone and he kept it on all the time in the front end along with an echo-plex so I am sure it helped to soften the blow. #005 also does not have the DC coupled CF as this too helps to compress the bottom end as well. This a big reason why I recommend something like #002 that has that feature to their SSS's. I got a chance to play a High Plains drifter a while back and IMO struggled a bit to control the low end (in a closed back cabinet). I would imagine this is why Eric used his with the Tube Screamer as it's a great dirty rhythm tone. SRV ran his the same way with a Screamer (Texas Flood Dumbleland) is another good example of that style amp w/ Screamer. IMO although it's a great clean amp (with a little spring reverb) I consider it too clean and needs something in the front end to give it some texture. This is just my opinion

Hope this helps

Tony

[rootz]

So this seems in line with my findings Tony, that is good to know!

On a side note: the 005 does have a DC coupled CF driver. At least all the Steel string Sultans from AN do. Which is a clone of a hpd, which is a clone of 005.

Some measures I took to control low end better: smaller bass pot, 250k. The bass pot now has a tail resistor of 1k, instead of 10k (skyline) or 1k8 (classic).

Next I’ll check for improvement. If no improvement:
- lower feedback resistor to get low end more under control in power section;
- adjust filter section. I don’t see a 390k resistor for the first step in some pictures. Instead there seems to be a 100k resistor.
- adjust the 1meg//33p combo preceding the filter. Lowering the resistor leads to less scoop and a bit more high end.

Ideally I would begin with an amp as close to the original as possible and tweak from there. Now I just need to find someone with the missing info. Those people seem to be very very scarce these days

[talbany]

On a side note: the 005 does have a DC coupled CF driver. At least all the Steel string Sultans from AN do. Which is a clone of a hpd, which is a clone of 005.

Rootz
Your'e right.Thanks the correction. For some reason I thought the HPD was driverless? Old age
Tony

[Bombacaototal]

Hi Rootz and Tony, I agree, this amp has an overwhelming amount of low end. I did modify mine to accommodate my personal taste

[rootz]

Yeah, but man does it sound good with a tube screamer!

I converted to partially classic stack. a250k bass pot and b100k mid pot. Not a big difference but noticeable.

Next I'm going to rewire the CF positive supply to a separate node, the way I suspect it is (or IMHO should be) in the 'original' clones of Brandon and Taylor. The PI will then come of the 4k7 resistor on the PSU board, as does the string of resistors for the preamp and reverb. It is either this (based on all pictures I saw) or the PI on a separate node. In a 150W version with 500+ V on the plates, it does not make sense to me to run the CF positive almost at screen supply voltage (although resistors are a fair bit bigger in size and value). The CF will be happy with me, as as it is both plates of the 12ax7 waste 700mW in heat.

In yet another picture I think I can Identify the small ceramics on the preamp board both as 500p. Seem to be yellow Ceramite new production?

And In yet another picture the value of the cap on the cathode of v1b is visible: 684k, so 680n. The cathode resistor is clearly 1k in other pictures. I consider these values now visually confirmed in one example of the Steel String Sultan.

[rootz]

There is the bypass cap value.

[talbany]

Hi Rootz and Tony, I agree, this amp has an overwhelming amount of low end. I did modify mine to accommodate my personal taste

My 002 has 4.7uF throughout but does have the modified filters the amp does have plenty of low end as long as it's tight and not farting out I can set the contour with the filters and the Mix w/ bass control , so I really have not felt the need to do any other mods to mine. 002 is as we know an earlier SSS circuit and has the different (DC coupled)mixer circuit, Classic style EQ and only has one feedback loop and is a little more "raw"sounding IMO so perhaps these alter the low end response time in #005, probably?? (be glad it's not a Dumbleland) The HPD amp I played was more Raw sounding and little faster punchier but didn't spend much time with the filters, cabinet's, guitars or rooms?
https://ampgarage.com/forum/viewtopic.p ... 914#p84914
BTW. On the video i posted Eric runs his bass control above noon through a closed back cabinet, not shy with the low end (But sounded great with a Tube Screamer ) It's personal taste thing.

Tony