New Tube Preamp project

Discussion in 'Tube Gear' started by Tleung, Oct 6, 2018.

  1. I always wanted to have a 6SN7 preamp. My last attempt was converting my 56 Pre to 6J5 Transformer couple line stage. It is being rebuild atm because of the hum issue. One of my buddy recently build an simple 6SN7 2 stage preamp. It is from the VTV valley issue 11.

    It sounded very nice but a bit forward. In this project I will be modify the power supply section adding a choke and 1 more stage RC filter.

    I happen to have some old stock of Holco and Caddock resistors that match the value require.

    It is a one gain stage with a Cathode follower design.

    Just finish drilling and sanding the chassis. Just put on first coat of primer.
    20181002_214148_HDR.jpg 20181006_144852.jpg 20181006_144901.jpg
     
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  2. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    This should be fun. :)
     
  3. Wntrmute2

    Wntrmute2 Junior Member

    Subscribing
     
  4. StevenZ

    StevenZ Active Member

    Cool. Looking forward to your progress.
     
  5. Well painting almost done. One more coat of blue paint and some light sanding will be ready for clear coat. 20181009_225247.jpg
     
    Last edited: Oct 9, 2018
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  6. Looks nice! Your project brings back memories for me. I built the VTV design 15 or 20 years ago and had a good time with it. I later rebuilt it with the Dick Olsher “Blue Velvet” circuit. There’s a lot you can do with one octal socket per channel.
     
  7. Interesting design by Dick Olsher. Do you recall the main difference between to two Amps. I know the VtV version is very simple and RAW. I am more curious about the sonic different.
     
  8. It’s been a long time since I had either of those 6sn7 circuits in my system so I can’t be very specific. I do recall the VTV had a huge soundstage with good depth; and the bass wan somewhat weak and hollow sounding. I preferred the sound of the Blue Velvet but there was something about it that I didn’t like. At this point I can’t remember any more details.
     
  9. Wntrmute2

    Wntrmute2 Junior Member

    Do you have schematics for the pre?
     
  10. I have the schematics at home but both are available on the internet. Olsher wrote an article describing the Blue Velvet in enjoythemusic.com.
     
  11. Here is a link to the Blue Velvet article (schematics are attached):

    http://enjoythemusic.com/magazine/equipment/1103/midmonth/bluevelvet.htm

    I looked online for a schematic of the VTV Octal but the links no longer work. It's very basic---just a simple gain stage directly coupled to a CF---and as I recall there were some errors in the voltages shown on the schematic.
     
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  12. Well two layer of clear cost and light sanding in between using 400 to 1000 and finish with 2000 wet sand paper. I am happy, last process buffed it using a hand buffer. Now start mounting hardware for dry fit. I like the looks so far. 20181011_224921.jpg
     
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  13. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    Beautiful work, Tony. :)
     
  14. Redboy

    Redboy Knobophobe

    That's a bold choice in color, Tony... and I like it!

    I hate painting, though. Hate it... so a "raw" industrial finish suits my projects just fine. :)
     
  15. Redboy

    Redboy Knobophobe

    Ooh, and I spy a Cerafine... wish I had more of those laying around!
     
  16. opa1

    opa1 Moderator Staff Member

    It's looking really nice! :)
     
  17. @Redboy I hear you regarding painting. Took me many hours to work on one chassis. I need to wait till it is all dry before sanding. All my gears are silver and black, so I was thinking a splash of colour will be fun. I already set my eye on Ferrier Red as my next project colour.

    @Redboy what value of Cerefine Cap do you need? I might be able to spare couple.

    Thanks everyone for the encouragement, I wasn't 100% sure about the colour until I look at the finish product.
     
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  18. Wntrmute2

    Wntrmute2 Junior Member

    Has that "old school" classic race car look to it. I dig it too.
     
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  19. Just finish the back of the line amp. Also some of my Cerafine stash 20181012_211325.jpg 20181012_211341.jpg
     
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  20. billfort

    billfort Administrator Staff Member

    This looks interesting Tony and wow, blue paint - haven't seen something like this in your room, I like it!

    You're on a tear of late too - seems just a few months ago we were talking about you starting to build again and you are almost 2 pre-amps and a pair of amps in!
     
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