rootz wrote: ↑Tue Aug 29, 2023 10:09 pm
The voice of the 005's I did was rather aggressive, especially when I pushed the preamp. Totally clean they are rather scooped sounding, with an abundance of bass frequencies. The main contribution here? 220k feedback resistor. At least that is what can be seen in all AN 005 derivatives. I tried multiple tone stack configs, but ended with a250k, b100k, a250k TMB and a very gradual high filter with low values ranging from 0 to 390 pF. One of those amps is now on stage with Nalle Colt and is undoubtedly one of the best clean amps I ever heard. Takes pedals really well, not overly bright even through an Alnico Blue in a pine Lazy J cab. I think I used a 100k feedback resistor in his amp. And it has 4x6V6 in the power amp, Bassman transformers. Works very well with hum buckers too. An amp you won't regret building!
Thanks for all this info Bas. I am building another one this Christmas and I will try the same PI values and v1 cathode setup as yours . I also ended up with a 250K, 100K , 250K TMB and I did the same gradual High filter as you did and it was very pleasing to the ears. Yes these amps tend to be Bass heavy as well but in a nice way!
Cheers
Guy
A quick note: the loop you use works best before the master volume. I see the value of the feedback resistor is not the standard 2meg2 anymore. Have you confirmed that you get enough signal from the first lnd150 to provide effects with? Otherwise you might end up with a horrible signal to noise ratio.
On another note: the zero loss fx loop was meant to be used before the master volume, but used some slightly different component values.
No I have not verified. I haven't actually implemented the loop yet, the circuit as drawn is more of a placeholder and aspirational lol. I might not even use an internal loop and just leave passive jacks.
I am close to fire up on this one though! Stay tuned
"It's like what Lenin said... you look for the person who will benefit, and, uh, uh..."
beasleybodyshop wrote: ↑Tue Sep 26, 2023 1:40 pm
Updated Schematic with some annotations. Thanks to Martin Manning and Gil Ayan for the additional information on PI Balance procedure:
SSS5-modded-with-loop-v3.pdf
Echoing rootz, nice schematic. Which application did you use for that?
Thanks Stephen. I use Inkscape. It's a free vector based image creator software, similar to Adobe Illustrator. My implementation is probably a crude approach but I built a library of objects and just start connecting assets together. I also use it to build layouts. Big shout out to Robert Hull (formerly with Tube Depot) for the help learning the software and with building layouts and schema with it.
Going to do the big fire up tonight!
"It's like what Lenin said... you look for the person who will benefit, and, uh, uh..."
beasleybodyshop wrote: ↑Tue Oct 03, 2023 3:07 am
Thanks Stephen. I use Inkscape. It's a free vector based image creator software, similar to Adobe Illustrator. My implementation is probably a crude approach but I built a library of objects and just start connecting assets together. I also use it to build layouts. Big shout out to Robert Hull (formerly with Tube Depot) for the help learning the software and with building layouts and schema with it.
Going to do the big fire up tonight!
Crude? I wouldn't say so unless you wanted it to perform electrical calculations. Kudos to you for gathering the library of objects. For work on layouts in Illustrator I've had to spend hours and hours on such an activity. I like the clarity of your work here and it's given me some ideas for improving the schematics I produce in DipTrace.
Well I finally got this thing working, really pleased with how it sounds out of the gate.
I went with marshall/tweed PI values. Amp has great sustain. The low end punch is wild, and with the step filters i was able to dial in complementary tones from a handful of cabs i have laying around the shop.
The Reverb does sound great but it is different. Might be the spring tank im using but it has a ton of decay, and you really have to dial in the reverb control to make it play nice. But once dialed in you could ape some really cool plate reverb type sounds.
Subbing the EP-3 preamp in lieu of the generic dumble FET was a solid choice, hands down. Thickened up the tone in a very musical way.
I added a 3 way global feedback switch on the back: 4.7K/100K/No feedback and damn, with zero NFB it turns into a marshall plexi on steroids. Did not suffer from the saggy looseness that amps tend to have when you disable the GNFB. Maybe I can chalk that up to the post PI driver? Amp in 100K NFB mode does great JTM/bassman overdrive tones when cranked, and clean tones are really, really good. This amp excels at the "clean at edge of breakup" type thing that musos love.
Am really pleased with Martin Manning's filter implementation. Sweep across both High and Low filter registers was excellent. All very useful settings and was great for dialing in different cabs. Those filters seem to be great for that kind of thing.
The only issue I have left is resolving an odd ground loop:
If you turn the master volume and presence control all the way down, and flip the amp off standby there is a moderate ground loop type hum. You can make this go away by turning the master up to around 3 o'clock OR turn the presence control up past noon. This all goes away when you disconnect the Global feedback loop. I've tried moving the ground around for the presence pot but that doesn't seem to change it all that much. hmm. Any ideas?
"It's like what Lenin said... you look for the person who will benefit, and, uh, uh..."
Running a quad of 6CA7 at approx 445vDC plates I get right at 80w of power before the waveform starts to clip. Not bad! Will try to shoot a decent soundclip to share at some point.
"It's like what Lenin said... you look for the person who will benefit, and, uh, uh..."
beasleybodyshop wrote: ↑Tue Oct 03, 2023 9:39 pm
Running a quad of 6CA7 at approx 445vDC plates I get right at 80w of power before the waveform starts to clip. Not bad! Will try to shoot a decent soundclip to share at some point.
Congrats on your power up! I also experienced the marshall style break up on mine once I ran it with 6550 tubes and took the GNFB to above 50k. Many people think this SSS is just for clean tones but as both of us have discovered they get some gnarly driven sounds happening too!
Thanks
Guy
Last edited by Guy77 on Sat Oct 07, 2023 1:51 pm, edited 1 time in total.
So GNFB was causing this hum issue I was having. I realized I had the feedback on the 16 ohm tap. I have a variable feedback switch that toggles between 100K, none, and 4.7K feedback resistors. I guess the ratio of NFB was too high with 4.7K swapped it to 68K and on the 4 ohm tap and no more hum, abd it sounds glorious. The clean tone is really amazing. The amp is very dynamic. Tried through a cab with EV12s and a cab with WGS creamback clones and it slays with the creambacks. Definitely an amp worth building!
"It's like what Lenin said... you look for the person who will benefit, and, uh, uh..."
swapped it to 68K and on the 4 ohm tap and no more hum, abd it sounds glorious. The clean tone is really amazing. The amp is very dynamic. Tried through a cab with EV12s and a cab with WGS creamback clones and it slays with the creambacks. Definitely an amp worth building!
