Results 1 to 21 of 21

Thread: Sweetening 5E3 overdrive

  1. #1
    Senior Member
    Join Date
    Dec 2008
    Posts
    757
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0

    Sweetening 5E3 overdrive

    I work on guitar amps, but my background is as a keyboard player. I've got a client who bought a 5E3 kit built by someone else (a Weber kit, I think), and he asked me to de-bug it. He thought that there was a problem with the speaker, but that turns out not to be the case. The scope shows me that what he doesn't like about the amp is that it has a kind of unpleasant overdrive tone, which he perceived to be a speaker malfunction. Swapping different speakers makes no difference.

    I've tamed it somewhat by adding a grid-stopper resistor to the input of the phase inverter, but it still has a kind of "ragged" sound when driven hard. And, because it's only 14 Watts, it's easy to drive hard. I've had to explain to the client that this amp is very different from his DRRI, despite it being a Fender circuit and having a 2 x 6V6 output section.

    So, I'm wondering: what is the great appeal of the 5E3 design? I've heard other 2 x 6V6 amps from this era, like the Multivox Premier 120 that seem to sound better "out of the box," without a lot of tweaks and mods. Or is successful tweaking and modding part of the fun of building one of these? :-)

    All that said, any further tips on how to make this amp sound a bit sweeter when overdriven? I've been through it carefully, and there's absolutely nothing "wrong" with it. It's just the circuit itself. Is this where the Paul Ruby zener mod might come in handy?
    Thanks in advance for any advice!

    P.S. Coupling caps are all 0.022uF Sozos, and we have played with cathode bypass values without success.

    0 Not allowed! Not allowed!

  2. #2
    Supporting Member
    Join Date
    May 2006
    Location
    Staffordshire UK
    Posts
    3,360
    Thumbs Up/Down
    Received: 7/0
    Given: 12/0
    How big did you do with the grid stopper? 1M is fine, won't cut treble (due to there being no voltage gain) and may help to smooth it out.
    My take is that because there's no mid scoop / not much treble boost, there's not enough treble from the instrument for power amp harmonics to 'mingle in' with, causing them to stand out rather.
    Putting in a 6G3 vol/tone mixer arrangement seems to help with this, and also as the 2nd stage may be exhibiting blocking distortion as stock .
    Also the VB+ can be near 400V with some transformers / rectifiers, which can be good for a hard edged rock tone, but ~350-360V can sound sweeter.
    Pete.

    0 Not allowed! Not allowed!
    Last edited by pdf64; 01-07-2012 at 05:33 PM. Reason: typo

  3. #3
    Senior Member
    Join Date
    Dec 2008
    Posts
    757
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    I used 470k, but I can go higher.

    0 Not allowed! Not allowed!

  4. #4
    Old Timer
    Join Date
    Jun 2006
    Posts
    3,315
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Have you tried the Normal/Mic Channel at very overdriven settings? Should be rich & creamy.

    A 5V4 might help it hold together a bit longer before going ragged (if uncorrected plate voltage exceeds ~385vdc consider a 300-330ohm cathode resistor too) but "ragged" & "unpleasant" don't sound typical of a properly working 5E3. If it sounds like the amp is malfunctioning...then it probably is. Though as you point out, it's got little in common with a DRRI.

    Can you post pics of the circuit? These amps can be sensitive to layout & wire routings...even if voltages & components are OK.

    0 Not allowed! Not allowed!

  5. #5
    Senior Member hasserl's Avatar
    Join Date
    May 2006
    Posts
    988
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Getting the goods from a 5E3 circuit is all about player technique. For one thing, you've got to ride the guitar volume control; you're always making adjustments with it. Another is picking dynamics. Players that are not accustomed to tweed style amps have problems with this, especially the guys that always crank the guitar volume all the way up and never adjust it, that is a recipe for farty, blatty, distorted tone; and doubly so when using humbucker pickups. 5E3's played well can be one of the sweetest tones ever, and like a Telecaster, there are so many different tones available by varying the controls and playing techniques.

    With that said, I too like to cut some of the bottom end using some smaller coupling caps and a 4.7uf cathode bypass cap. But I have played many stock 5E3's and have no problems getting great, great tones from them. Again, it's all in the player's hands. He needs to develop his technique. Keeping in mind he'll never have a lot of headroom out of that circuit. If that's what he's wanting, it's the wrong amp.

    0 Not allowed! Not allowed!

  6. #6
    Senior Member
    Join Date
    Dec 2008
    Posts
    757
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    MWJB,

    Again, I'm not really a guitar player, so I'm not that articulate when it comes to discussing the different flavors of overdrive. I'm not sure I'd be able to identify "rich & creamy" overdrive if I heard it. I play enough to determine if an amp is working properly or not. This is really the first time I've worked on a DIY amp built and sold by an amateur amp builder, and it looks like it was reasonably well-done to me. I fixed a few iffy solder joints, but nothing major.

    This amp produces a clean sine wave on a scope that calculates to 14W, which should be about right. Cathode voltage is +22V with a 270 Ohm cathode resistor, and cathode-to-plate voltage is 360V. Tubes are NOS Sylvania 6V6GT, GE 12AY7 input tube, JJ ECC83 gain stage & PI, and CBS Hytron 5Y3WGTA. The current owner is a talented, but younger guitar player, and, in the end, I'm not entirely sure that this is the amp he really wants.

    I did install a 1 Meg grid stopper on the PI, and that seems to help. As you requested, I'm attaching a pic of the build.

    Click image for larger version. 

Name:	IMG_2549.JPG 
Views:	254 
Size:	916.1 KB 
ID:	16737

    0 Not allowed! Not allowed!

  7. #7
    Senior Member
    Join Date
    Dec 2008
    Posts
    757
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by pdf64 View Post
    How big did you do with the grid stopper? 1M is fine, won't cut treble (due to there being no voltage gain) and may help to smooth it out.
    I went up to a 1M grid-stopper, and that did, in fact, smooth it out. I appreciate the help!

    0 Not allowed! Not allowed!

  8. #8
    Junior Member
    Join Date
    Jan 2008
    Posts
    11
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Try bumping up the grid stoppers on the 6V6's, as high as 100K and see if that helps.

    0 Not allowed! Not allowed!

  9. #9
    Old Timer
    Join Date
    Jun 2006
    Posts
    3,315
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    I think you have an extra "0" in there? ;-)

    0 Not allowed! Not allowed!

  10. #10
    Junior Member
    Join Date
    Jan 2008
    Posts
    11
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Nope, I meant one-hundred-K. Refer to the "Avoiding unpleasant overdrive tones" paragraph here:

    The Valve Wizard

    0 Not allowed! Not allowed!

  11. #11
    Old Timer
    Join Date
    Jun 2006
    Posts
    3,315
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Needing 100K grid stoppers on a 5E3...or anyother Fender based design is a sure sign that you have bigger issues elsewhere.

    0 Not allowed! Not allowed!

  12. #12
    Senior Hollow State Tech Bruce / Mission Amps's Avatar
    Join Date
    May 2006
    Location
    Denver, Colorado
    Posts
    3,045
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by Rhodesplyr View Post
    MWJB, ...
    This amp produces a clean sine wave on a scope that calculates to 14W, which should be about right. Cathode voltage is +22V with a 270 Ohm cathode resistor, and cathode-to-plate voltage is 360V. Tubes are NOS Sylvania 6V6GT, GE 12AY7 input tube, JJ ECC83 gain stage & PI, and CBS Hytron 5Y3WGTA. The current owner is a talented, but younger guitar player, and, in the end, I'm not entirely sure that this is the amp he really wants.

    I did install a 1 Meg grid stopper on the PI, and that seems to help. As you requested, I'm attaching a pic of the build.

    Click image for larger version. 

Name:	IMG_2549.JPG 
Views:	254 
Size:	916.1 KB 
ID:	16737
    It looks good to me too. I think it is a kit from Ceritone ... looks like one of their painted or powder coated chassis. I don't know what they use for output transformers but a cheap one can make a difference too.
    360v plate to cathode is a little high for classic 5E3 tone but still OK.
    14 watts output is high too... was that measured into a speaker or a dummy load and at what frequency?
    After many many hundreds and hundreds of these amps... I also run into players who simply just cannot squeeze "the tone" out of a tweed amp! ha ha. You might have to reconsider it and suggest something else.

    0 Not allowed! Not allowed!
    Bruce

    Mission Amps
    Denver, CO. 80022
    www.missionamps.com
    303-955-2412

  13. #13
    Senior Member
    Join Date
    Dec 2008
    Posts
    757
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    All problems were solved with the 1 Meg grid stopper on the phase inverter. Both the sound and the trace on the scope testify to the improvement.

    0 Not allowed! Not allowed!

  14. #14
    Senior Hollow State Tech Bruce / Mission Amps's Avatar
    Join Date
    May 2006
    Location
    Denver, Colorado
    Posts
    3,045
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    OK cool.. I would say that you should never need a 1M grid stopper resistor on the 5e3 PI so.... I don't know what the actual problem was and probably still is.
    Regardless, I live by this rule:
    #1 What ever sounds good, is good.

    0 Not allowed! Not allowed!
    Bruce

    Mission Amps
    Denver, CO. 80022
    www.missionamps.com
    303-955-2412

  15. #15
    Supporting Member
    Join Date
    May 2006
    Location
    Staffordshire UK
    Posts
    3,360
    Thumbs Up/Down
    Received: 7/0
    Given: 12/0
    In Rhodesplyr's other 5E3 thread, a speaker change is detailed. The original speaker was a vintage PA type with a wizzer cone; that may have been responsible for some harsh/unpleasant overdriven tones.

    0 Not allowed! Not allowed!

  16. #16
    Senior Member
    Join Date
    Dec 2008
    Posts
    757
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by Bruce / Mission Amps View Post
    OK cool.. I would say that you should never need a 1M grid stopper resistor on the 5e3 PI so.... I don't know what the actual problem was and probably still is.
    Regardless, I live by this rule:
    #1 What ever sounds good, is good.
    A big part of my business is fixing organs, which are often fairly complicated; if I can somehow miss a problem in a circuit as simple as a Fender Tweed Deluxe, I should just put a gun to my head and be done with it :-)

    The 1 Meg resistor addition fixed the initial complaint, which matched the description exactly of the sound of an overdriven cathodyne phase-splitter on the Valve Wizard site. That complaint was resolved with the Jensen whizzer-cone speaker still installed. That speaker, however, still had some odd higher frequency resonances that I'd wager are part of the whizzer cone, and the amp sounded better matched to most other speakers. It's possible that the whizzer cone accentuated the behavior of an overdriven phase inverter.

    0 Not allowed! Not allowed!

  17. #17
    Noodle of Reality Steve Conner's Avatar
    Join Date
    May 2006
    Location
    Glasgow, Scotland
    Posts
    7,251
    Thumbs Up/Down
    Received: 6/0
    Given: 0/0
    My feeling is that the story goes like this.

    Guitarist of younger generation builds a 5E3 kit.
    To test it he plugs in a cheap guitar with overwound humbuckers and bashes out some power chords.
    The poor 5E3, dragged into the 21st century, protests with a noise like a diarrhea stricken pig.
    Another "Farty distortion in 5E3 plz help" thread appears on the MEF.

    A whizzer cone certainly won't help matters either.

    0 Not allowed! Not allowed!
    "Enzo, I see that you replied parasitic oscillations. Is that a hypothesis? Or is that your amazing metal band I should check out?"

  18. #18
    Junior Member
    Join Date
    Nov 2006
    Posts
    17
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Just curious, was there any specific reason that the bypass cap was left off the 1.5K resistor on V2? I read back twice and saw no mention of it.

    0 Not allowed! Not allowed!
    Last edited by Trout; 01-13-2012 at 03:56 PM.

  19. #19
    Supporting Member deci belle's Avatar
    Join Date
    Jan 2010
    Location
    Santa Fe, NM
    Posts
    374
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    The poor 5E3, dragged into the 21st century, protests with a noise like a diarrhea stricken pig.
    hahaha!!!

    0 Not allowed! Not allowed!

  20. #20
    Member
    Join Date
    Dec 2012
    Posts
    54
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by Bruce / Mission Amps View Post
    OK cool.. I would say that you should never need a 1M grid stopper resistor on the 5e3 PI so.... I don't know what the actual problem was and probably still is.
    Regardless, I live by this rule:
    #1 What ever sounds good, is good.
    ..which can unfortunately often be right before the amp dies.

    0 Not allowed! Not allowed!

  21. #21
    Member
    Join Date
    Jun 2008
    Location
    upstate NY
    Posts
    85
    Thumbs Up/Down
    Received: 0/0
    Given: 1/0
    Just to clarify, are you guys talking about putting a 1M resistor on pin 7 of V2? (I know this is a very old thread, but I just came across it!) Thanks.

    0 Not allowed! Not allowed!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Spanish 5e3 low overdrive
    By RedRooster in forum 5 E 3
    Replies: 14
    Last Post: 03-22-2011, 04:50 AM
  2. ef86 overdrive ?
    By mtx11 in forum Theory & Design
    Replies: 2
    Last Post: 03-01-2009, 10:25 PM
  3. Overdrive and Reverb
    By luthierwnc in forum Theory & Design
    Replies: 4
    Last Post: 02-01-2009, 11:27 PM
  4. Quality of overdrive
    By brebis in forum Vintage Amps
    Replies: 4
    Last Post: 12-30-2008, 07:34 AM
  5. overdrive circuit
    By drlowlow in forum Theory & Design
    Replies: 3
    Last Post: 01-16-2007, 12:36 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •