Two rock crs v3 clone and v1 vs v3 differences

[rootz]

Hi Niki,
Thanks for the kind words. What do you mean by the ltspice files? There are many. The ones containing the designs, but also files with the tube models, parts, transformer models. Looks like I should just make a post here on this forum with all files I use, for others to use too and hopefully improve.

And jazzbass, I'm still pretty much out of spare time to do a clean demo of the amp...

[Synchu]

That will be great. Thanks.
Niki

[tylerbaster]

Hi, rootz

Thank you for generous sharing! Two-Rock mentions CRS that, “It has a separate isolated power supply for the reverb, which enhances the reverb effect and prevents loading of the dry signal. In conjunction with our other reverb innovations, you’ll immediately notice a rounder, warmer, less restrictive feel.”
https://www.two-rock.com/portfolio-item ... signature/

We can see 2 sets of diode rectifiers for High Voltage on the power supply board here.

Have you tried “separate isolated power supply for the reverb” ?

[rootz]

No, never used a separate power supply for the reverb. Looks like a lower voltage winding for that purpose and 35W mode? Can’t see what component is between the PSU caps.

Then again, is that a CRS V3?

Can’t see how a separate power supply would prevent loading the dry signal. If anything, loading by the reverb driver stage makes the signal rounder, because you load the v1b output with it. Loading would make the amp sound warmer, not less loading.

[bepone]

Nice isn’t going to cut it I’m still not getting the famous Dumble bloom and feedback thing. Maybe I should just turn it up louder and forget about the neighbours for a couple of minutes. Seriously, how loud should one get before feedback happens? I’m rather positive I’ve got my lead dress right. I’d share gut shots to check on that if anyone can help me with this (would share them anyway).

Those hifi amps are EL34 monoblocks. EF184 long tail pair (two tubes per phase inverter), cascode constant current source on the ltp, schade feedback from the output tubes, Lundahl transformers, Mosfets driving the output tubes (class AB2), Ultra linear. Based on designs from pete millet, SY, gingertube (baby huey) and ideas from George/tubelab on diyaudio.com. Have to dig some further to find the schematic again.

sorry for OT.. i saw this just now . Dumble sound you cant get without volume, but you allready know that.

im interesting in the second actually, EL34 is lets say "not made" for AB2 class, or is existing very limited info about. it is pure audio pentode made for convenctional drive in AB1. did you empirically arrived to this idea ? i see that you have A2 drivers, some advanced topology but aren't you affraid to burn g1? actually i building the same, EL34 PP, but with normal drive, just finished transformers and pcbs.

if is too much OT you can also respond on PP , thx

[rootz]

No problem. My hifi amps are as much class AB2 as some of the Steel String Singers with CF drivers: not much. Sure, the MOSFETS can deliver more current, but that is not their main purpose. I wanted an amp free from blocking distortion. This does just that.

Just fished an SSS 005 with a CF driver and a quad of 6V6 output tubes. Not sure about the AB2 capabilities of them, but they do deliver some 60 clean Watts, without blocking distortion. The output stage just compresses a bit. No farting out, no massive amounts of cross over distortion, no nothing.

Both my hifi amps and the SSS are very dynamic amps with lots of authority in the bass. I think the CF (or SF) certainly helps with the latter.

[bepone]

No problem. My hifi amps are as much class AB2 as some of the Steel String Singers with CF drivers: not much. Sure, the MOSFETS can deliver more current, but that is not their main purpose. I wanted an amp free from blocking distortion. This does just that.
..
Both my hifi amps and the SSS are very dynamic amps with lots of authority in the bass. I think the CF (or SF) certainly helps with the latter...

understand from the bass aspect, completelly. + AB2 class helping with the transients of course. output stage is sucking the current from the driver out how is arriving the peak over the maximum and there is no more coupling cap to do charging/discharging cycles. g1 grid resistance how is increasing the current in it is droppig to low levels and load for the driver became high, and huge maybe.

this is now my concern, and question-. tubes for A2 class are mostly transmitting pentodes, tetrodes, triodes which have perfect linearity in positive area!
per example my favorite tube of all time, SRS551, or RS1003 which is a beast, built for A2 torture , in the datasheets you can find stated grid g1 alowed power Pg1 max=0.5 Watts!

the same for the 2E22, direct heated pentode, geat linearity in A2 area, increased even more with grid g3 drive! in datasheet you can find grid driving power of 0.55 watts!

6L6GC has AB2 statements in datasheets, also 6V6 can be abused those are transmitter tubes..but EL34 in my mind was always used in "audio" A1, AB1 topologyes because i never find grid g1 max available power in any paper. and it is easy to burn that with mosfet follower in constant overload use.

but this is all theory. good to find real usable data, and that is working without problem in the life. i'm sure you never use hifi amp at max long time , more like 5-15 watts in daily use and you are not stressing too much EL34's

[bepone]

i need to say that this thread i find very amusing to read, has a lot of usable info, but from the name of the thread i will never find them , i just open this unintentionally

[bepone]

to respond also here..always good to respond on time

I doubted for a while to build a ported cab, based on the drawings/Thiele parameters of EV. Reports about them being beamy, more difficult to mike than an open back cab and the the fact that they are narrower than the head I build, stopped me from building one. Your best advice would be to just build one and listen for myself, right (really looking for an excuse to start a new project here, haha)?

i have built 3 TL806's and you cant miss with the build.i like them a lot.. it is good and correct sounding cab.. one box was from the cheap particle board and still was good!

if you are interested here is a list of the speakers i remember from the tests that working good in this box:

EVM12L (of course it is built for this )
Celestion G12-65
Weber 12F150 (thin in open cabs but very good in TL806)
----------
Not (so) good (muddy)
Celestion Alnico cream (muddy)
Celestion Creamback M65
EVM 12S (too much middle)

i have a lot of videos with TL806.. video with EVM12L and restored Ampeg V4, 100W+ on it
https://www.youtube.com/watch?v=F-OR8utP8jM

here is one with deluxe reverb "replica"
https://www.youtube.com/watch?v=RJmnSDC0I6E

here is one with JTM style DIY
https://www.youtube.com/watch?v=RCKrnRTlYVY

[tylerbaster]

Thank you for your reply
[quote] Looks like a lower voltage winding for that purpose and 35W mode? [/quote]
Exactly. Loop & Reverb recovery node is fed by the lower voltage winding regardless of the 50W or 35W mode.

[quote]Can’t see what component is between the PSU caps.[/quote]
Could you tell me which component are you referring to ? I will be happy to confirm.

[quote]is that a CRS V3? [/quote]
The pic and schematic I posted are CRS V1.Sorry for my ignorance. I noticed CRS V3 has two tube rectifiers.
CRS V1, CRS V2 and John Mayer Signature seems to have the separate isolated power supply.

CRS V3
http://www.mts.org/audio/wp-content/upl ... oInnen.jpg
CRS V1
http://www.mts.org/audio/wp-content/upl ... Q60_57.jpg
http://www.mts.org/audio/wp-content/upl ... g60_57.jpg
CRS V2
http://www.mts.org/audio/wp-content/upl ... CN0029.jpg
http://www.mts.org/audio/wp-content/upl ... 2Innen.jpg
John Mayer Signature proto?
http://www.mts.org/audio/wp-content/upl ... -Proto.jpg

[imo1]

Hey Roots!

I'm really digging on your take on this design. This is what I'm leaning towards as well.
Wanted to see your thoughts on the amp now that you have had it for a while. Did you end up sticking with the initial schematic that you listed or did you change anything? I didn't see the files in the files section, but maybe i missed it.

Ian

[jazzbass]

No, never used a separate power supply for the reverb. Looks like a lower voltage winding for that purpose and 35W mode? Can’t see what component is between the PSU caps.

Then again, is that a CRS V3?

Can’t see how a separate power supply would prevent loading the dry signal. If anything, loading by the reverb driver stage makes the signal rounder, because you load the v1b output with it. Loading would make the amp sound warmer, not less loading.

Hi tylerbaster, hi rootz,

what voltage does the transformer have in the 35W position? I ask this because I suppose that the difference with the 50Watt position is only a minor filtering due to the difference of the first capacitors, 47uf against 110uf.
I can be wrong but I don't see what advantage it has to power loop & reverb recovery with lower filtering than the 50W position.
The same reasoning applies to the higher power version of the amplifier.

Franco

[imo1]

@rootz
I'm curious as to which design you actually built. Did you use the later schematic(comparison between 124, JM, and crs V3) or the early one that you listed for general design? I thought you followed the general pre of the low plate..100K plates, etc, but the schematic you referenced has the higher gain pre with the EQ of the low plate.

Mainly interested because the amp sounds so good!!!

[jazzbass]

Hi Tylerbas,

perhaps in a hi-fi realization of great value it would make sense but I have my doubts that in an amplifier for musical instruments it constitutes even a small advantage.
The purpose of the instruments for making music is to "build" a sound while that of the Hi-Fi industry is to reproduce the sound as faithfully as possible, but also the realization of this desire is influenced by external factors, the listening room, the type of furniture and their quantity, the absorption or reflection of the walls and the environment ... practically an excellent Hi-Fi, however immersed in an environment, reproduces its own truth with respect to the live performance, also influenced by the environment where it is performed ..... so I believe that Two Rock represents a study, an exercise that in any case must find the approval of the consumer.

Ciao, Franco

[jazzbass]

Hi everyone,

I just finished (almost ... I have to replace the choke I get today) the Steel String Special thanks to the very generous help of Rootz, it's a wonderful amp.

Now I would like to build the CRS v3 following the indications of this discussion because I must admit that I miss the distorted sound (there is always the hand of Rootz to stimulate my and your curiosity)

I have available a chassis purchased from Tubetown, a good part of the components and a power transformer from InMadOut, the model TA M50 34, primary 0-220-230, secondary 3.15-0-3.15; 340-0-340; 0-5, which should be right for 2 x JJ 6L6.

The power transformer was purchased for a project I didn't do and I'd like to use it now. Do you think it might be suitable?

P.S. sorry for my ignorance but ... the 100K trimmer on the relay board corresponds to the U28 of the wiring diagram (and with this question I found out, you will certainly understand that I am an absolute beginner in electronics)

Thanks
Franco