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

[Bombacaototal]

In my opinion 002 is a completely different amp, fairly agressive and snappy and punchy due to the higher gain circuit, but it also has a very tight bass. I run mine with bass pot at maximum and a couple clicks on the low filter. The difference in bottom between 2 and 5 has a lot to do with coupling capacitor sizes and filtering. They are both great amps and the filters do allow for a lot of tweakability in regards to fine tuning the voicing. They do sit in different sonic footprints tho

[talbany]

Here is a really good video of John noodling straight into 002



Back to too much Bass
Tony

[Guy77]

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.

Hi Bas congrats on a great sounding and great looking amp!

As I mentioned in our email I built a modified version of this amp without the step filters. I also ran my DC cathode follower off a separate node on the Power Supply board. I also did not want to run my Cathode follower tube at the same high voltages as the power tubes.

As I increased the size of the dropping resistor, which in turn dropped the B+ voltages on the Cathode follower, the bass became less tight and a little more compressed sounding. The amp became warmer sounding . I liked this change.

Merry Christmas and Happy Holidays everyone!

Guy

[Bombacaototal]

Here is a really good video of John noodling straight into 002



Back to too much Bass
Tony

Thats not 002, it's Two Rock Oak cliff special, which is their version of 002

This is the actual 002 through a PRS cab which is a bandmaster clone and has a lot of bass (I have that exact cab). You can hear how tight the low end is even in such massive cab and like me, Mayer cuts his high filter almost all the way and really pushes the bass pot

https://youtu.be/xdIQRrhiQAw

[rootz]

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

I think 002 and 005 are not comparable aside their name. Yes, you can see some similarities, but the concept of the preamp is very different. 002 is loaded with feedback loops, 005 has just one in the reverb. Classic vs (partially) Skyline, tweed mixer vs modified Fender reverb, etc.

In the added schematic and plots you can see the rather dramatic effect of the 1meg//33p combo before the filter. The smaller you make the resistor, the more gain and high end (relative to the bass). Also the mid scoop is somewhat less prominent. I think V2a in a 002 could receive more signal, but then again, the filter section is implemented differently in the amps too!

I have no real means to know what the preamp voltages in the real 005 are or should be. My calculations based on Taylors versions of the amp, lead me to believe the preamp voltages are actually quite low, around 170V for v1a. Much lower than in 002. Also because of the lower value cathode resistor on v1b and lack of feedback loops around v1, it is pretty easy to get some mild overdrive from v1(b). I do think it is a bit one dimensional with just overdrive from the preamp. I think a TS808 is more suited. 005 feels like it was meant as a big clean machine and platform for a fuzz and tube screamer.

Do you know the voicing of the HPD you played? Or all they all the same? I seem to recall Brandon offered more voicings. I don't find my amp particularly raw, but certainly punchy.

[rootz]

In my opinion 002 is a completely different amp, fairly agressive and snappy and punchy due to the higher gain circuit, but it also has a very tight bass. I run mine with bass pot at maximum and a couple clicks on the low filter. The difference in bottom between 2 and 5 has a lot to do with coupling capacitor sizes and filtering. They are both great amps and the filters do allow for a lot of tweakability in regards to fine tuning the voicing. They do sit in different sonic footprints tho

Agreed. The filters in 005 are very helpful, especially the high filter. With every click I gain another frequency band that emphasises part of the guitar. I don't like filters with overdriving the front end of 005 very much yet. Might need some more tweaking.

[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.

Hi Bas congrats on a great sounding and great looking amp!

As I mentioned in our email I built a modified version of this amp without the step filters. I also ran my DC cathode follower off a separate node on the Power Supply board. I also did not want to run my Cathode follower tube at the same high voltages as the power tubes.

As I increased the size of the dropping resistor, which in turn dropped the B+ voltages on the Cathode follower, the bass became less tight and a little more compressed sounding. The amp became warmer sounding . I liked this change.

Merry Christmas and Happy Holidays everyone!

Guy

Hi Guy!

I called you last week and left a message, have some board shots for you.

I do have the step filters on dual layer 6 position switches. This means that when my low filter is on 0, a 7 step filter would be on 1 (390k engaged). That is already a pretty big step in lows, so I might adjust the 390k resistor to 100k.

Interesting observations on the CF positive voltage. I really like the firm and fast low end the amp has now, but certainly interesting to test some values.

Also merry Christmas to you, your relatives and anyone else here too!

[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

I think 002 and 005 are not comparable aside their name. Yes, you can see some similarities, but the concept of the preamp is very different. 002 is loaded with feedback loops, 005 has just one in the reverb. Classic vs (partially) Skyline, tweed mixer vs modified Fender reverb, etc.

In the added schematic and plots you can see the rather dramatic effect of the 1meg//33p combo before the filter. The smaller you make the resistor, the more gain and high end (relative to the bass). Also the mid scoop is somewhat less prominent. I think V2a in a 002 could receive more signal, but then again, the filter section is implemented differently in the amps too!

I have no real means to know what the preamp voltages in the real 005 are or should be. My calculations based on Taylors versions of the amp, lead me to believe the preamp voltages are actually quite low, around 170V for v1a. Much lower than in 002. Also because of the lower value cathode resistor on v1b and lack of feedback loops around v1, it is pretty easy to get some mild overdrive from v1(b). I do think it is a bit one dimensional with just overdrive from the preamp. I think a TS808 is more suited. 005 feels like it was meant as a big clean machine and platform for a fuzz and tube screamer.

Do you know the voicing of the HPD you played? Or all they all the same? I seem to recall Brandon offered more voicings. I don't find my amp particularly raw, but certainly punchy.

rootz
Before I look over the schematic again,a couple quick questions
1. How (or why) did you come up with the 170V V1 calculation? and why did you alter RK in V1 and what were you trying to achieve? (sonically) by going there? also how much distortion are you looking to get or is your problem just bass related or both?

2. The HPD I played was a very early ones IIRC it had a Skyliner stack, the reverb was very Fendery. It had a tendency to want to breakup sooner (on attack). had faster response time(tighter) vs mine which wanted to compress and sustain instead. (at around the same vol levels) 002 is more scooped in the mids (Classic)has a clearer bell like chime on the top end of the reverb signal vs the Fender style which is slightly darker. Thats what I mean by "Raw" sounding The best way to describe it is? more in the direction of that of a Super Twin (with pushed mids)
there was really no better or worse just different. Brandon told me he preferred the more raw sound of the later SSS's
3. The last would be the use of the Tweed mixer/buffer in 002

BTW.I did try bypassing the filters and this gave me some cool preamp distortion so I can see where that mod you described would alter gain/tone there. I messed around with it and went back stock. If I were to add more gain (or a boost switch) Thats where I would put it.

At the end of the day for me it's a one trick pony! a CLEAN/clear, dynamic muscular current generator w/a wide bandwidth and natural compression/sustain, very musical touch sensitive instrument I use as a platform for outboard gear

(I have a Reverend II I use for dirty rhythm and a modified (LED clipper)TS-808 w/Burr Brown op amp loaded for the violin thing. If I want just a little boost I use a TC Electronics RC Booster and an old Boss DD2-Digital delay for some slap back delay. Thats it no fuzz)
Hope this answers all your questions?
Tony

[rootz]

Hi Tony, I didn’t exactly come up with 170V for v1a. Instead I followed all values from the pictures I have: 4k7 and 10k or 47k on the PSU board (see pictures a bit earlier in the thread) and a string of 15k-820r-1k on the can cap. Sometimes Taylor adds a 150k or 220k at the last node on the can cap as a FET emulation. All values I have are from amps in the smaller chassis Taylor uses. If I’m correct, those are 22, 50, 75 or 100W amps (150W only in the big chassis). So I assume he uses Twin iron for the 100W version. That should give around 450V on the plates of the output tubes, right? I remember Brandon saying he had 515V on the plates, but probably with a slightly different dropping string (again, Taylor uses a different dropping string in the bigger chassis too).

With those assumptions and values I end up with 170V at v1a.

V1a has standard 1k5//4u7 cathode combo.
V1b is different. Not altered by me (the opposite actually), but taken directly from pictures. In one I could clearly see a 1k resistor, in another (posted above) I can read the value (684k so 680n). Keep in mind, I’m trying to clone a clone (AN SSS) of a clone (HPD) of the real 005. Brandon has had 005 on the bench.

What can be confirmed, tone stack wise: 10n mid cap, 47n or 100n bass cap and a 2n cap for mid boost, all on the preamp board. Also visible: 150k slope resistor. So Skyline values on the board. What I can’t see: pot values. There is one picture from Taylor where the pot values are written on the chassis; classic stack values.

The HPD you played, did it have Skyliner pot values too and a 1n cap over the bass pot? I can’t find pictures with a 1n cap on the bass pot.

[talbany]

Hi Tony, I didn’t exactly come up with 170V for v1a. Instead I followed all values from the pictures I have: 4k7 and 10k or 47k on the PSU board (see pictures a bit earlier in the thread) and a string of 15k-820r-1k on the can cap. Sometimes Taylor adds a 150k or 220k at the last node on the can cap as a FET emulation. All values I have are from amps in the smaller chassis Taylor uses. If I’m correct, those are 22, 50, 75 or 100W amps (150W only in the big chassis). So I assume he uses Twin iron for the 100W version. That should give around 450V on the plates of the output tubes, right? I remember Brandon saying he had 515V on the plates, but probably with a slightly different dropping string (again, Taylor uses a different dropping string in the bigger chassis too).

With those assumptions and values I end up with 170V at v1a.

V1
Great thanks for the explanation! Ok so for the sake of accuracy lets go with what we know about the original
IIRC Brandon had his custom made by Heybour. AFAIK Dumble raised his voltages in his 150W 6550 loaded amps and has been known to use Peavey (Duce/Ultra/5150) Iron in his 120W amps. we don't know for sure what Iron is in the original but Ill bet ya it's more than likely 510V (under load)
So if Taylor figures his version was only 100W and used 6L's so he didn't need the higher voltage transformers but at the same time could compensate for that by adjusting his dropping string then OK I get it? Do you know for sure Taylor used stock Twin iron? or did he too call Heybour?
170V on V1 sounds low? to me for an amp designed to be clean. At that lower voltage on V1 the amp will be darker, (scoop the mids) and a looser bottom end with less headroom. AFAIK Dumble ran a few of the earlier ODS amps a little lower 180V but have not heard of anything 170v?? . I believe mine runs just a bit under 200V and the supply side of V1 on the drawing has 298 VDC.
So perhaps this is contributing to your bass heavy sound (I would start there)

V1a has standard 1k5//4u7 cathode combo.
V1b is different. Not altered by me (the opposite actually), but taken directly from pictures. In one I could clearly see a 1k resistor, in another (posted above) I can read the value (684k so 680n). Keep in mind, I’m trying to clone a clone (AN SSS) of a clone (HPD) of the real 005. Brandon has had 005 on the bench.

Somewhere I have some shots of the HPD I'll dig those out and take a look and get back after Christmas Ok?

The HPD you played, did it have Skyliner pot values too and a 1n cap over the bass pot? I can’t find pictures with a 1n cap on the bass pot.

I think it was a stock Skyliner but will double check that as well! when I get more evidence.


Merry Christmas everyone
Have a safe Holiday!

Tony

[rootz]

I remember reading Brandon using Heyboer transformers too, but can't remember the source.

I can confirm getting 515V with Deuce transformers, at least when on 220V primary tap and my 226V (230V nominal) wall outlet.

I assumed Taylor uses pretty standard 100W iron, but also would like to check that. I believe he used to use Classic tone?? Let me see if I can dig up some pictures to 'prove' this, as your questions are more than valid. I also tend to agree 170V looks about 30V too low.

With the lower bass pot value, slightly adjusted low filter and some other small tweaks the bass is now really under control. The low value global negative feedback resistor of 220k contributes a lot to the big bass.

It would great if you can check some values!

Happy holidays Tony

[talbany]

I remember reading Brandon using Heyboer transformers too, but can't remember the source.

I can confirm getting 515V with Deuce transformers, at least when on 220V primary tap and my 226V (230V nominal) wall outlet.

I assumed Taylor uses pretty standard 100W iron, but also would like to check that. I believe he used to use Classic tone?? Let me see if I can dig up some pictures to 'prove' this, as your questions are more than valid. I also tend to agree 170V looks about 30V too low.

With the lower bass pot value, slightly adjusted low filter and some other small tweaks the bass is now really under control. The low value global negative feedback resistor of 220k contributes a lot to the big bass.

It would great if you can check some values!

Happy holidays Tony

Rootz
Wife kicked me out of the kitchen so I have some time and looked over what I have. Sorry I cannot share the shots
Power supply configuration
1.PT is FWB rectified, This feeds the plate supply. After the STBY is a 500 ohm resistor/Choke This feeds the screen supply and is filtered
2. Then followed by a 10K 20 watt wire wound power resistor
3.This feeds the 3rd filter which branches off to the plates of the C.F driver and the cap can
4. The last cap on the board is isolated by a 560 ohm resistor and feeds the PI trimmer
5.Input to the cap pan looks to be a 15K resistor this feeds the reverb output transformer and mixer/recovery filter cap
6.Also coming off the 15K goes through a 2 ohm safety resistor that gets filtered and goes out to V2
7.Followed by a 1K oxide to the last node of the cap that feeds the FET board junction that also feeds V1

Given he used a resistor and not a choke and FWB rectifier implies that he used Peavy iron in the original

As far as the Bass control He uses Alpha pots (No labels) and I do not see a cap hanging off the top and bottom of the pot. I do see the resistor but cannot tell what value it is?

So I just noticed that your using 6V's correct? If so your going to have to lower the GNFB resistor because the 6V's generate a lot less current than the 6550's to get the same effect.
Also The preamp in 005 is designed and voiced for a 150W high powered output section so that may also be part of your bass problem so give it plenty of GNFB

That's what I got! it let me know if something doesn't look right and I'll take a 2nd look later!
Good Luck

Tony

[Guy77]

Hi Guy!

I called you last week and left a message, have some board shots for you.

I do have the step filters on dual layer 6 position switches. This means that when my low filter is on 0, a 7 step filter would be on 1 (390k engaged). That is already a pretty big step in lows, so I might adjust the 390k resistor to 100k.

Interesting observations on the CF positive voltage. I really like the firm and fast low end the amp has now, but certainly interesting to test some values.

Also merry Christmas to you, your relatives and anyone else here too!

Hi Bas, yes got your voicemail thank you. Yes I would love to see shots of your boards!
I just sent you an email , let me know if you got it.
Please reply with your board shots!

I also love to run all my amps with at least 200v on V1. I just find that that the amp comes to life more and has a little more volume than running things at 170v

Thanks
Guy

[rootz]

Thanks Tony, looks I got it right first time 'round! I swapped the CF and PI supply later and that was a mistake.

I tend to agree that Dumble probably used Peavey iron. I wonder, however, how those transformers would keep up with the heater demand of 4 6550's and 5 preamp tubes. Seems a bit much for a Deuce transformer. Then again, didn't the PT on EJ's amp fail?

Anyway, with the values you give me, I still end up with barely 170V on the plates of V1a, even with 515V on the plates of a quad of 6550's, 500 Ohm resistor before the screens and a 10k 20W dropping resistor for the CF (and the rest of the string).
I think there is no discussion about the values of the resistors on the can cap. That should be 15k -> 820r -> 1k. I'm looking at a HPD gut shot showing those exact values (also posted in this thread on p1 or p2).

I guess the tone pot values come down to preference. For now I'll work with classic stack values.

And yes, 6v6's power tubes. I've always wanted to try a quad of them on (too) high voltage. It will sound different from 6550's of course, but consider this an experiment. I'm pretty sure the chassis I'm using could house a quad of 6550's, but it for sure would need active cooling (aside from other transformers and accompanying fork lift).

The nfb has to be adjusted. A pure 150W would deliver almost twice the current. I'll see where I end up when I connect the nfb resistor to the 16r tap. That will help with the low end for sure.



Guy, I'll get back to you on dm and send you the pictures.

[beasleybodyshop]

I suspect a big part of the low end issue people have with this amp is going to be very low amount of NFB - therein lies the rub though, as you change the dynamic character of the amp. JM2C.