You're welcome Guy. Your transformer choice sounds like the beginning of a hefty and great tone machine!
When working with a 5V transformer and (I guess) 5V relays, you might not have enough voltage to keep the relays switching via a foot switch IF you implement the F/S like I did. The advantage of my way is you only need a 3 conductor cable and two stereo jacks to get the F/S working and not 5 conductor and 5 pin DIN plugs like in a normal ODS. Chances are that you can borrow a 3 conductor cable with stereo jacks from a sound engineer at a gig if you forget to take yours with you. A DIN plug Dumble cable? No chance (I think).
Dumbleators are big . I need something like a Minimix. Or something simple like: input -> attenuation with resistors -> buffer -> send volume -> jacks -> return volume -> recovery -> output. Will piece something together on a experiment board.
I did not use the 1meg/68k combo. I went for 470k/68k. There is a master volume just before these resistors, so no need to dump loads of signal again. With the master on the front and back wide open, you'd have plenty signal to drive any output to saturation I guess. I get almost 100V p-p with the back master on 10 and the front on 6. More than enough for my needs (any needs actually).
I like the cut control too, but tried a presence again. So far, I like it. Gives some good bite to the sound.
You do not have the required permissions to view the files attached to this post.
yep, believe me, I know enough not to be dangerous in that way. ;^}
I've built several ODS amps, JM, countless fenders, marshalls, voxes and variants.
It's the integration of the reverb circuit I'm working on now.
rootz wrote: ↑Tue Oct 01, 2019 4:38 pm
You gotta know what you're doing to not be dangerous! That being said: if you work cleanly, slowly and always keep one hand in your (back) pocket while doing measurements, you start minimising the chances that you'd electrocute yourself. What also helps, is making test setups in LTSPICE. I can highly recommend that. Always safe and as long as your parameters are right, predicted outcomes will only slightly vary from reality. For example: I designed the whole PSU in Spice and was off by about one volt.
Now what you also should do is look as much at schematics from Fender, Mesa, the ones here, etc. to get a better understanding of what circuits do. Implementing reverb is pretty simple when you use a 2 tube (4 triodes) like in many Fenders. Paralleled driver triodes (12AT7), half 12AX7 recovery and half 12AX7 mixer, just like in the schematic above. Which works, that is essentially the Two Rock Jet or the CRS v2 (and countless other amps probably). Jet users rave about their cleans and reverb (but who wouldn't after paying 2 grand for an amp that size).
Keep safe, high voltages in these amps are lethal!
Excellent diagrams rootz! I am excited to build mine and will report back with my finding later this Nov/Dec. Sounds like you have yours tuned just were you like it.
Yes dumbleators can be too large and cumbersome. If I go with a 50 or 20 watt version I will probably use the 372fx or 372hx transformers. I have heard good things about the 300 series and would like to try one.
Did you find that the reverb was sufficient (I am not expecting surf style reverb from this implementation ) with just the 1/2 tube driver as opposed to the full tube driver in the JM?
Chat later
Sorry Barry, for a brief moment I thought you were not so experiences with tube electronics. Sounds to me now, you are up to the task to figure out how to make a reverb work. Out of curiosity: for what kind of amp are you looking for a reverb and what have you come up with so far?
Guy, I'm using a 370FX in this amp. Less voltage than I'd like, but it had been very reliable for the past 5 or 6 years 9since I got it.
The reverb is not as deep as that of the JM amp, but more than enough for my needs. A single 12ax7 triode seems up to the task to drive the reverb. I use a 3 spring long decay tank. You could use a 12AT7 as driver/recovery tube. The lower plate impedance might be a better match for most reverb transformers.
I let you be the judge on te reverb. Here's a snippet with both send and return of the reverb on full. There are ways to get much more reverb out of the circuit, but I don't need that.
Thanks for posting these great pics rootz and thanks for the sound demo!
Great attention to detail in your work!
The reverb is very nice sounding and more than enough . I can't wait to start mine.
Your JJ 6v6 tubes sound excellent with what ever plate voltage the 370fx is providing!
I always liked my 6v6 tubes running around 350 - 385v and it appears yours are in that range, I don't like them when they are over 400v.
I swear I had a RAR file of someone turning a V3 inside out on here... someone posted it, multipart RAR of a well-documented V3 signature in a blue anodized chassis.
You do not have the required permissions to view the files attached to this post.
brentm wrote: ↑Fri Oct 04, 2019 4:28 am
CRSig3-50RectoInnen.jpg
I swear I had a RAR file of someone turning a V3 inside out on here... someone posted it, multipart RAR of a well-documented V3 signature in a blue anodized chassis.
Never that collection of pictures. I do have a large collection of pictures of a crs v1 in a black chassis. Posted by some paisley tele. Are you sure it isn’t that collection?
rootz wrote: ↑Fri Oct 04, 2019 7:17 am
Never that collection of pictures. I do have a large collection of pictures of a crs v1 in a black chassis. Posted by some paisley tele. Are you sure it isn’t that collection?
A quick follow up on the last few posts. I changed the tone stack to a classic, so now it is a #124 crs v3. This suits my taste better than the skyliner. Cleans are now much more like the Wonderland this amp used to be.
I recently did a couple of gigs with the amp. With the right speaker this amp is plenty loud for a pub or smaller stage. I use it as a monitor mainly, but always miked up. It misses the balls of a large output section though. I could always easily tell the difference between a 50 and 100 Watt amp, and I can hear this one has a smaller power section. Just less oempf if you know what I mean.
I never got as many compliments about my lead sound as I do now, with this iteration of the crs v3. None of my Marshall clones not the Trainwreck Rocket have this amazing singing quality, authority and sit so nice in the mix. Turn the amp up a bit and power chord roar. Still smooth and a bit polite. Never out of control like my jtm45 can get. I really like this amp too with strats and Les Pauls. Emg’s sound pretty good too.
Now much depends on speakers and cabs. I want my rig to look more in line with the traditional Dumble look, so time for some cabinet building. My now new 1x12 with EVM12L is 24 inch wide 13 deep. What I’d call oversized. Compared to my old combo, it sounds like hitting the loudness button when I plug in that new cab. Detailed, bright, smooth. I couldn’t believe the difference a new cab made.
So that is where my new ‘job’ starts: converting my current build to a chassis that fits my new combo and head. Yes, I made two places to go for one amp! I’ll probably will build a new amp anyway, a bit more along the lines of the TR Coral maybe. We’ll see. anyway, here are some (pretty shabby) pics of the cabs.
You do not have the required permissions to view the files attached to this post.
Beautiful looking cabinets rootz! I like the diamond pattern grill.
I also find I am always tweaking things after finishing a build. I imagine it one way in my mind but then when its done I want a different sound and out comes the iron lol.
In my case it was a 102 lowplate/skyline I just finished building and I realised I wanted my overdrive a little tighter and ended up with a highplate v2 and lowplate v1.
Thanks for all the nice words guys! It's been a few weeks, so I've done a couple of gigs with the new cabs.
It's still to early to judge if I like my new Creamback Neo is the combo cab, I have just done one gig with it. So far, I like what I'm hearing, but it's nowhere near as nice as the EVM in the 1x12 I think.
Next step would be (yes, tweaking) to go to better transformers. I'd like to do a 40/20 version of this amp first. To do that I first need to get clear what I want to Savino, the owner of Inmadout in Italy. I need some clones if the 022814 and 022855 for an amp that can do 40/20 with a quad of 6V6's or 50 with a pair of 6L6's. Now that I'm at it, where can I find specs on the trannies? I can only find specs on replacements from Hammond and Classictone.
The PT should be something like 330-50-0-330 @ 240mA?
A big plus when ordering from Savino: I can add a 6/12 V winding to the transformer for relays and a hefty 5V winding for dual GZ34 rectifiers.
Just to tease some new pictures. Still need to get some decent sound samples...
You do not have the required permissions to view the files attached to this post.
. I need something like a Minimix. Or something simple like: input -> attenuation with resistors -> buffer -> send volume -> jacks -> return volume -> recovery -> output. Will piece something together on a experiment board.
