1. Win a Broadcaster or one of 3 Teles! The annual Supporting Member Giveaway is on. To enter Click Here. To see all the prizes and full details Click Here. To view the thread about the giveaway Click Here.

Project: Low Watt With Reverb

Discussion in 'Shock Brother's DIY Amps' started by jchabalk, Oct 3, 2020.

  1. jchabalk

    jchabalk Tele-Meister

    Posts:
    490
    Joined:
    Mar 11, 2009
    Location:
    Northern California
    Like many of you i imagine i've been playing more in my house and given that amp building season is upon us i'm thinking of a new build and am looking for some suggestions.

    I've been thinking about what i want and it would be along the lines of a Tweed Princeton with a 12" speaker and reverb. Maybe a switchable tone stack from champ style -> TMB for a little more control?

    I'm sure this isn't breaking new ground and figured i'd check here as a lot of you are pretty well familiar with low wattage builds like this - and suggestions or pointers i should check out?

    Given that i've got a little more time and flexibility on my hands lately i'm also thinking i might take a stab at building and finishing the cabinet for this one. I'm thinking tweed style but am looking around at other options now too.
     
    WalthamMoosical likes this.
  2. jimgchord

    jimgchord Tele-Afflicted

    Age:
    47
    Posts:
    1,426
    Joined:
    Apr 3, 2018
    Location:
    victor,ny
    For me the added stuff wasnt worth the hassle on such a small amp when there are so many good verb pedals out there.
    Cabinet finish options are endless. Heres a tweed princeton with no tweed....
     

    Attached Files:

  3. wabashslim

    wabashslim Tele-Afflicted

    Age:
    69
    Posts:
    1,944
    Joined:
    Nov 26, 2005
    Location:
    Sonorous Desert
    That's what I concluded too. I was going to put reverb & trem into the empty area in my Plexi-6V6 chassis but since I didn't originally plan for that the extra wiring next to the power section would have been a noisy nightmare. I bought a Strymon Flint instead and I'm very happy with it. The faceplate covered the extra holes.

    upload_2020-10-3_11-2-15.png
     
  4. Paul-T

    Paul-T Tele-Meister

    Posts:
    484
    Joined:
    Nov 23, 2018
    Location:
    London
    A good number of people have put a 1-tube reverb into a Princeton and it probably costs good amount less than a Strymon Flint.

    My next project is a Deluxe Micro with 1-tube reverb. I have a backup in the form of tube-town's LND reverb too. Most of the cost, obviously, is in the reverb spring, so it doesn't hurt the wallet too much to find a few bits and experiment

    I haven't tried this, but this is Tubenit, from the el34 forum, with a suggestion for a 1-tube reverb in that circuit.
     

    Attached Files:

    Last edited: Oct 3, 2020
  5. sds1

    sds1 Tele-Afflicted

    Age:
    44
    Posts:
    1,564
    Joined:
    May 4, 2017
    Location:
    Orlando, FL, USA
    The one-tube circuit as a drop-in reverb is limited in that you can only do so much wet/dry mixing without going the Fender route -- which is to attenuate a majority of the dry signal in the mixing stage, then recover the losses in a following stage.

    To this effect I now consider the Fender reverb a 2-tube reverb because it won't work without the recovery stage. Also FYI you don't really need parallel 12AT7 driver, a single triode is fine. The 12DW7 is probably the ideal tube for the 1-tube reverb.

    Sorry for the unsolicited brain dump on that but I recently got done with several iterations of revision to the 1-tube reverb trying to achieve Fender-style amounts of reverb and I wish the info out there had a better disclaimer as to its inherent limitations and how it actually performs. It's still a nice reverb but even on 10 I could never say it's too much and probably not enough for many folks.
     
    King Fan, wabashslim and jchabalk like this.
  6. sds1

    sds1 Tele-Afflicted

    Age:
    44
    Posts:
    1,564
    Joined:
    May 4, 2017
    Location:
    Orlando, FL, USA
    You'd be switching between a lossy and non-lossy tone control, therefore there is a big gain boost in the tweed/champ style mode. Just something to think about, it would be cool but know it's way more than an frequency response adjustment.
     
    King Fan likes this.
  7. tubedood

    tubedood Tele-Holic

    Age:
    55
    Posts:
    501
    Joined:
    Sep 25, 2018
    Location:
    Orlando
    Awww sorry to hear the little 1 tube reverb with a 12DW7 doesn't add much reverb to the sound... I was thinking of trying it in a PP6V6 build. Might have to go the traditional transformer style.

    The single tube 12DW7 reverb I was thinking of trying doesn't use a transformer.. similar to an old Ampeg style.
     
    Last edited: Oct 3, 2020
  8. Paul-T

    Paul-T Tele-Meister

    Posts:
    484
    Joined:
    Nov 23, 2018
    Location:
    London
    Ah, good info, do you have a thread on that?
     
  9. jchabalk

    jchabalk Tele-Meister

    Posts:
    490
    Joined:
    Mar 11, 2009
    Location:
    Northern California
    Awesome, thanks so much for the comments and suggestions. I probably should have said in the original post that this project is probably equal parts filling time and trying to build something just a bit out of the ordinary - i also have a good deal of spare parts. I've built a handful of fender and marshall circuits previously and in many ways this amp would be somewhat redundant to those, my favorite all around is my 5e3 but it tends to be too loud to play in my house and i really like adding some reverb to it - ideally without having to break out a peddle.

    I'm going to check into a couple of these that you've suggested, i'm also going to spend some time playing my tweed princeton through the speaker in my deluxe, and a 2x12 cab i've got here too and try to further dial in which direction i want to go.
     
    sds1 likes this.
  10. sds1

    sds1 Tele-Afflicted

    Age:
    44
    Posts:
    1,564
    Joined:
    May 4, 2017
    Location:
    Orlando, FL, USA
    The 1-tube reverb still uses a transformer. It's very similar to the Fender circuit in many ways. But the mixing/recovery is where things get different. You could say it's more about the implementation of the reverb circuit than the circuit itself.
     
  11. sds1

    sds1 Tele-Afflicted

    Age:
    44
    Posts:
    1,564
    Joined:
    May 4, 2017
    Location:
    Orlando, FL, USA
    No but if you started one I would surely jump in to add my 2 cents, and would be super curious to hear other folk's take on the matter as well.
     
  12. tubelectron

    tubelectron Tele-Afflicted

    Posts:
    1,539
    Joined:
    Nov 25, 2010
    Location:
    France
    @jchabalk,

    Here is a one-tube reverb that I designed and use with success on several of my compact amps :

    [​IMG]

    The reverb transformer can indeed be a regular 022921 Fender one. IIRC the reverb unit is a 8AB3C1B from Belton-Accutronics, fully damped in a bag and shielded. But as you can see, the following gain stage must offer a recovery gain of 5.05/0.651 = 7.75 to retrieve the initial input voltage.

    The amp below is an example of implementation of that single tube reverb circuit :

    [​IMG]

    It's a compact amp but not a low watt though : 23WRMS clean tone on a 8" 100W Eminence speaker. Size comparison with a SF PR :

    [​IMG]

    That said, the reverb circuit is of course convenient for a low watt amp, just assuming you can provide the recovery gain of circa 7.8 ;).

    -tbln
     
    jchabalk, Jlwctn, dunehunter and 2 others like this.
  13. tweedy_woodpecker

    tweedy_woodpecker Tele-Meister

    Age:
    49
    Posts:
    142
    Joined:
    Jun 25, 2019
    Location:
    Austria
    I‘ve built a parallel SE 6V6 amp with full Fender style reverb and TMB where the middle pot also acts as a raw control where you can gradually take out the tonestack and get less gain loss and more tweed style tones which I really like. It makes it a very flexible amp and I think it could be more useful and less complicated than a switch and two seperate tonestacks.

    For home volumes you could also use only one 6V6...nice cabinet by the way!
     
    jchabalk, Jlwctn and sds1 like this.
  14. RollingBender

    RollingBender Tele-Afflicted

    Posts:
    1,340
    Joined:
    May 14, 2011
    Location:
    SW Minnesota
    I’ve built 4 amps with the Tubenit 1-tube reverb. Not quite capable of Dick Dale but generally more than you ever really need (usually sitting at 3 or 4 on the reverb dial).
     
    tubedood and Jlwctn like this.
  15. sds1

    sds1 Tele-Afflicted

    Age:
    44
    Posts:
    1,564
    Joined:
    May 4, 2017
    Location:
    Orlando, FL, USA
    Which 4 preamps were in play?

    It may have much to do with how much signal is passed to the reverb circuit, less dry signal means higher wet mix potential.

    I had better luck with it on an 18W circuit for example, than D-style circuits.
     
  16. printer2

    printer2 Poster Extraordinaire

    Posts:
    6,933
    Joined:
    May 24, 2010
    Location:
    Canada
    How do you find the tube-town reverb?

    I am in hurry-up-and-get-stuff-done-outside-before-the-white-stuff-arrives mode so I have not tried this yet. I want to make an add-on for a normal Champ with a single preamp tube. I have mid impedance tanks so low voltage seems to be the way to go with them. That can be high voltage for others if need be. The way out there part is taking the reverb signal from the grid of the second triode and the return signal from the tank sent to the cathode of the triode. I figure if temolo or NFB can be sent to the cathode circuit why not the reverb? It may require a cathode follower, or a mosfet source follower instead for less power requirements.

    The upside would be people being able to add reverb to their BF or Tweed amps with no modification other than soldering in a send line and a return. A SS circuit with adapter and tank might be a way to go with a reverb control on the back of the cab rather than drilling a hole in the amp. Anyway that is the concept. Will it give enough reverb? I do not see why not, but until I get around to doing it I can't say for sure.
     
    jonrpick likes this.
  17. Paul-T

    Paul-T Tele-Meister

    Posts:
    484
    Joined:
    Nov 23, 2018
    Location:
    London
    It's a back up for my Deluxe Micro, which I'm not near to starting yet (unless there's another lockdown) ; I'm going to build the board with space and power supply for a 1-tube and might well try with both that and the tube-town.

    Reports on the tube-town are very limited; compared to the Surfy-verb, though, you can use it at line level and it only cost $15 or so - transformer and tank will work with either, hopefully.
     
  18. EmWeAh

    EmWeAh Tele-Meister

    Age:
    40
    Posts:
    101
    Joined:
    May 9, 2019
    Location:
    Germany
    there is a tube-town forum with some posts about the LND reverb. Posts are mostly in German, but nothing google translate couldn't fix ;)...

    Edit: typos...
     
    Last edited: Oct 5, 2020
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.