Two rock crs v3 clone and v1 vs v3 differences

[rootz]

You got a great sound with the strat! Turning up treble and setting the presence between 4 and 7 does help the bloom.

Thank you Erwin! It's different from the Strat sounds from e.g. Matt Scofield. It's less bold, brighter. Might have to do with the home rehearsal volume I play on. Amps generally need turning up to come alive, Dumble or the likes don't seem different.

Treble was already up and presence was on at least 2 'o clock I think. I use a 2k5 presence pot, so need to turn it up a bit higher. Imho presence comes on really slow, I suspect that is a general characteristic with Dumbles.

[rootz]

sounds great Rootz. Nothing wrong with that at all. At gig volumes I'm sure that will open up even more and give you what you're looking for


Nothing wrong with Tonerider pickups. I've used them a lot. In fact I bought a set of boutique PAF's to replace the tonerider humbuckers in a guitar I had. I ended up putting the toneriders back in. They didn't work as well in that particular guitar.

M

Thanks Marcus. Chose the Toneriders for the glowing reviews and the price was hard to beat. Once heard a Les Paul at north sea jazz festival in The Hague and was floored by the sound. The guitarist works at a rather famous guitar store in The Hague, Max Guitar. I was their guest then. I asked him what that pickup was. Can't remember the name, but it was dirt cheap (€ 35,-) and from China IIRC. Moral: expensive pickups don't make a great sounding guitar, cheap ones aren't bad perse.

Had a friend over here just before lock down. Brought his amp in for repair (Bugera 333, actually a pretty nice amp if you're in for old school metal) and a cheap Hello Kitty Squier. That guitar had a Seymour Duncan JB in the bridge I believe. That thing sounded muffled through his amp, but like an articulate monster through my amp. I was so surprised I'm actually considering buying such a cheap guitar too. Might be hit and miss though. Moral 2: comparably dirt cheap guitar can sound stunning through a Dumble IMHO.

[rootz]

I'd be very happy with an amp that sounded that good! And even happier if I could play that well!

I think your demos sound great!

Thanks for sharing! I hope you'll enjoy the amp and not mod it too much away from the great tone you're already getting.

With respect, 10thtx

Thanks for your kind words Guy. I will enjoy this amp and it will stay this way for 99.5%. I actually love this #124 config also with humbuckers, more than I liked high plates with a Strat. Only mods I will do in the foreseeable future will be an upgrade on the OT to a deluxe (I now use a pretty cheap OT for a Marshall 18 Watter). Might experiment with 8k and 6k6 reflected impedance. Not sure what I will gain, but curious enough to find this out. The other mod will be to replace the 270p cap preceding the reverb send pot by a 470p one. Need a bit more mids in my reverb signal. That's it. After that I need to build a new amp. Luckily I have an empty combo cabinet for one

By the way Guy, you were working on a new amp when I started this one? Sourcing parts and ideas IIRC. How is that one coming together?

[Guy77]

I'd be very happy with an amp that sounded that good! And even happier if I could play that well!

Thanks for your kind words Guy. I will enjoy this amp and it will stay this way for 99.5%. I actually love this #124 config also with humbuckers, more than I liked high plates with a Strat. Only mods I will do in the foreseeable future will be an upgrade on the OT to a deluxe (I now use a pretty cheap OT for a Marshall 18 Watter). Might experiment with 8k and 6k6 reflected impedance. Not sure what I will gain, but curious enough to find this out. The other mod will be to replace the 270p cap preceding the reverb send pot by a 470p one. Need a bit more mids in my reverb signal. That's it. After that I need to build a new amp. Luckily I have an empty combo cabinet for one

By the way Guy, you were working on a new amp when I started this one? Sourcing parts and ideas IIRC. How is that one coming together?

Hi Rootz. I just started working on the amp this week. I have all my parts including some nice cow suede to cover the combo!
Here are some early pics. I will through in a 6th preamp tube so that I can run the tank with a full tube instead of half. I will let you know how it sounds in a week or 2.

Cheers!
Guy

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[rootz]

Oh man, that looks nice! Love the face plate, I still need to do a decent one.

You are aware you used my slightly older Two Rock layout? In the newer one I put the cathode resistors and caps right of the V1 circuitry. A little more true to a Dumble, but I couldn't hear any difference though.

I'd suggest to forget the 6th preamp tube. I think the drive is less because the reverb driver is after the master volume. So the master volume output limits the available voltage to the driver, thus limiting it. The dual recovery makes up for a lot of it, but don't expect reverb splash like in a genuine Fender reverb. If interested: I adjusted this schematic to a pre master reverb driver. You can run that with a 12at7 driver/first recovery. Should drive the tank a lot more.

Anyway Guy, this reverb with the driver post master does not leave much to want for if you want some extra ambience and warmth to you sound.

[Guy77]

Thanks for the update rootz! After reading your post I think I will prefer the Master vol after the mixer stage.
I found your other layout in the other post . Looks amazing as usual!

I noticed it doesn't have the full tube to mix the wet and dry signal. I wonder how that will effect the sound ,if any.
The hole is drilled so I may go full blown ODSR #60. I will sleep on it and decide tomorrow.
I will post my results when done.


Thanks again rootz!

Cheers!

Guy

[rootz]

Do you mean the other layout where I made a crossover between a SSS #005 and a #124? That is a very different reverb circuit and untested. I'm sure it will work though as it is more in line with the TR CRS v1.

However, I did do a schematic and comparison of the #124, Mayer TR and a kind of a cross between them. That is essentially a CRSv3 with the reverb pre master. Big difference: in the Mayer the reverb is taken from the volume pot wiper, in the CRSv3 it is taken from the master wiper. So in the latter amp you lose a double triode (pre driver and half the dual reverb driver). You can see that in the schematics below.

The graph shows a comparison of the clean output frequency curve. My design and the #124 are pretty close, mDb's difference. The Mayer is a bit of a different animal. low global negative feedback (12k instead of 4k7) and a contour control on top of a wide open presence account for most of the difference. High end is a bit subdued due to the pre reverb driver loading the high end after the volume control a bit. All of these differences can be made smaller by adjusting feedback, presence to contour and a bit of frequency shaping.

Putting the master after the reverb will require some tinkering. Certainly doable and if I had money to burn I'd already build an amp that way. But I seem to have more ideas than money lately

[Guy77]

Thanks for the update rootz. I see the similarities between the 2 schematics and how the Mayer is a different animal.
I will build mine similar to yours ( Post master vol reverb) and post an update when done.
I noticed the ODSR #60 schematic floating around on this forum also has the reverb coming after the overdrive stage .

Also regarding the level control I guess it could also function as a Master volume and get placed on the front of the amp and then place the other volume in the back. Do you find that you prefer adjusting the Level control on the back more to shape your tone or do you prefer having the Level in the back since you just set it once and leave it?

Thanks again rootz!

Cheers

Guy

[rootz]

I saw those #60 schematics and layouts too. Seems like a very interesting amp, but I'm not exactly sure how accurate the schematics I've seen are.

I've left the second master volume on the back of the amp. Easily accessible, but mostly set and forget in a live environment. The first master is the one like in a real Dumble. They both need to be turned up a bit to let the amp breath. I've got no bright cap on the first master, so no need to turn that one up far to get rid of exces brightness.

Reverb Send and Master on the back aren't always easy to operate because of their placement. But easy enough for me. Use some high torque pots (so not the Bourns low torque ones for example) and mount some round knobs. You'll learn to recognise them by touch very soon. At least I did.

[Guy77]

I finally finished this amp . Thank you for the work you did on this amp Rootz, this truly is an amazing sounding amp!!!
This has become my favorite amp by far! I think everyone should build this amp!

This amp is like having all the best qualities of the JM amp and the Overdrive Special all in one amp!

I made a slight change in my build, I added an extra preamp tube ( 6 preamp tubes instead of 5 ) this way I could use an 12AT7 to drive the reverb tank and another 12AX7 for recovery.
I was worried that this amp would not have enough reverb since the reverb comes after the Master volume but wow the reverb was amazing!!!
The reverb in this amp gets very intense and gets into surf territory !!

Here are the changes I made:

I used an extra preamp tube for the reverb (12AT7)
I used the JM classic tone stack with 100K slope resistor and 0.1uf bass cap, 0.05 uf mid cap and 0.001 uf treble cap.
I used Low Plate on V1 and High Plate on V2 for the overdrive channel.
I used the 1mg pot for Reverb Send and 1mg pot for the Level control. I believe you did this too rootz.
I built the amp to run 4 x 6V6 tubes and 410v on the plates.
I used a 33uf on v1 and a 33uf on v2 everything else was 22uf except first cap that was 47uf. There are 7 different B+ stages in total.

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Cheers!

Guy

[rootz]

That looks wonderful Guy, I love the changes you made to my (or better said Two Rock's) initial ideas. That is what it is all about: taking a design and tweaking it to your liking and needs.

Yes, I have two 1meg pots on the back for reverb send and global master volume. I have the classic tone stack too, bone standard #124. I run 410V on the plates of a pair of 6V6's, 22uF filtering for every node except output tube plates (47u) and reverb driver (no cap). Sims suggest a difference reverb response between filtering or not filtering the reverb driver node. Something I should look into deeper.

You say you use 6 preamp tubes. Have you just doubled on the reverb driver with a 12at7, leaving half a 12ax7 unused? Or did you use all triodes available? A schematic or clearer pictures or video would be very nice to have!

[Guy77]

That looks wonderful Guy, I love the changes you made to my (or better said Two Rock's) initial ideas. That is what it is all about: taking a design and tweaking it to your liking and needs.

Yes, I have two 1meg pots on the back for reverb send and global master volume. I have the classic tone stack too, bone standard #124. I run 410V on the plates of a pair of 6V6's, 22uF filtering for every node except output tube plates (47u) and reverb driver (no cap). Sims suggest a difference reverb response between filtering or not filtering the reverb driver node. Something I should look into deeper.

You say you use 6 preamp tubes. Have you just doubled on the reverb driver with a 12at7, leaving half a 12ax7 unused? Or did you use all triodes available? A schematic or clearer pictures or video would be very nice to have!

Hi Rootz. I just doubled on the Reverb driver with a 12at7 and left a half 12ax7 unused. I edited one of the schematics you posted showing the 7 separate B+ nodes I used for the amp and the 2 10K dropping resistors that I changed to 22K. The B+ on my reverb driver 12at7 is about 380v and the tube that I used was a Jan Phillips NOS 12at7wc.
I also used the .0047uf cap for the reverb pot instead of the .002uf. It gave the reverb more mids like you mentioned! This has become my favorite amp!
The ODSR #60 also uses this same setup for its B+ nodes ( with 1 extra node).

With several amps on this forum getting pcb designs I think this one would make an excellent candidate.

I will get a video done and post it here later.

Cheers!
Guy

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[jazzbass]

More video, now with a Strat. Pretty much a 62 clone, with cheap tone rider pickups. Again low volume home practicing, so not much bloom and feedback happening. Should practice more on my Robben Ford runs, oh well...

good, you sound really good. I love the sound of the Fender Stratocaster very much and would like to hear from you also a recording with the clean sounds of the amplifier. Thank you

[rootz]

Give me a couple of days for your request, I have a busy schedule this week.

[Synchu]

What a great sounding and looking amps. Loved the Strat video!
Amazing attention to detail and gotta love the LTSpice simulations.
I’m also using it quite a bit, esp. comparing tone stacks and it proved very useful and indeed quite accurate.

That said - do you guys mind posting the LTSpice files as well?

Niki