New amp build - EF86, 10w 6L6/EL34 single ended combo (in tweed)

Discussion in 'Amps and Cabs' started by eddy999, May 29, 2014.

  1. eddy999

    eddy999 Member

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    I wanted to build a nice simple clean combo to use as a pedal platform - as simple as it comes - power switch, volume. I only play in church and we always mic up the amps - my previous head/cab were overkill and more than i'd like to carry.

    The circuit is an EF86 preamp feeding a 6L6GC (or EL34) with a volume pot between the two - doesn't get much simpler than that. I based it on my previous 10w head, although I got rid of the power scaling and added a choke for better filtering without losing voltage (and volume).

    The build went surprisingly well considering it has been around 8 months since my last proper project. After all the voltages checked out for the initial power up I popped the tubes in and it worked beautifully. The noise floor is very low, no audible hum and only hiss at higher volumes. I'm very pleased with the lack of hum as my previous single ended amp originally hummed until I added an additional RC filter before the plates - that solution did however lose voltage through the resistor due to the entire amp's current draw feeding through it.. In this version I decided to try a choke with a low resistance before the plate feed - sounds great and the current rating is way above what the amp pulls so it should perform well.

    I had the cab built by Chris Uff (A UK cab builder who I found through Ampmaker.com) - he did a great job with the build and turned it around really quickly - highly recommended (chris@c-and-l.freeserve.co.uk).

    All I need to do now is mount the chassis in the cab (when my cage nuts arrive in the post that is) and sort out a faceplate.. I don't think i'll go with a laser etched plate this time - I'm going to experiment with some thin real wood veneers to keep the simple look. I used a pre-drilled chassis, hence the extra unused holes on the front panel.

    I decided on an Eminence Ragin Cajun for the speaker (10 inch). I haven't tried one before and i'm very pleased with how it sounds so far.

    I'm very pleased with how the amp turned out - the EF86 has tons of headroom and takes pedals really well, plus really sings when hit with a nice clean boost (i'm using a TC Spark). I'll add clips soon when I get the time to record them.

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  2. tele_jas

    tele_jas Member

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    Hey, Brits aren't supposed to use Tweed..... That's for us Americans! ;)

    Just kidding....That's a sweet n simple build (good looking too) and I bet it sounds amazing! Can't wait for the clips.
     
  3. cj_wattage

    cj_wattage Member

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    That's an excellent build, sir. Very compact!
     
  4. THiwaTT

    THiwaTT Member

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    that build looks great!
     
  5. sickboy79

    sickboy79 Member

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  6. Mattbedrock

    Mattbedrock Silver Supporting Member

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    That's elegantly simple. Very nice idea and nicely executed. Thanks for sharing!
     
  7. scorched

    scorched Member

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    Very cool. Any schematics?

    Looks like a great little project.
     
  8. eddy999

    eddy999 Member

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    A quick clean demo, some reverb and delay in places (from pedals rather than post-prod). More to come later on.

    [SOUNDCLOUD]https://soundcloud.com/eddy999-1/10w-combo-clean-demo[/SOUNDCLOUD]
     
  9. PGrant

    PGrant Member

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    Really cool build. But the guy that built the cab still has a Freeserve email address? LOL!
     
  10. eddy999

    eddy999 Member

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    Chassis mounted. I've ordered some wood veneer samples that should be big enough to cut into a faceplate - i'm interested to see how they turn out.

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  11. novel

    novel Member

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    Nice!

    With such a simple circuit, does it in fact stay clean and constant in character all the way up, or does it change with volume and reach breakup at a certain point?

    Sounds like a perfect clean amp/pedal platform.
     
  12. eddy999

    eddy999 Member

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    It stays clean and sounds the same nearly all the way, only starting to break up when nearly cranked. It seems with an instrument level signal my preamp only just has enough juice to start pushing the 6L6GC into overdrive (and sounds great doing it). When hit with a clean boost like the TC Spark however it is a different story and it breaks up much sooner (and is a fair bit louder too).

    As a clean platform for mic'ing there's plenty of clean headroom before it starts to distort which should suit my needs perfectly.
     
  13. eddy999

    eddy999 Member

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    I haven't updated the schematic but it is basically this, minus the vvr and with the choke instead of the first 240ohm resistor.

    http://pauledwards.co.uk/images/schem.png
     
  14. Lost_Cause

    Lost_Cause Member

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    I am very interested in doing this. What kind of guitar are you playing though the amp?
     
  15. eddy999

    eddy999 Member

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    A PRS Custom 24.
     
  16. Lost_Cause

    Lost_Cause Member

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    Thank you very much. So choke in place of r12 right? I have a few cabinets waiting for an amp.
     
  17. Lost_Cause

    Lost_Cause Member

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    Good to know you are playing a guitar with HBs and getting that sound.
     
  18. eddy999

    eddy999 Member

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    No it was R13 I swapped out for the choke, and I left out the B+ fuse and VVR also this time.
     
  19. zzmoore

    zzmoore Member

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    It's funny, when I first started Reading/Hearing about Variable Voltage Regulation...I could never understand the acronym.
    I always that people were typing
    WR
    which looks so much like
    VVR
    when it is all said and done..... ;) :)
     
  20. eddy999

    eddy999 Member

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    Yes I find that the Wariable Roltage works really well on the whole, just not necessary in this build. :)
     

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