Recent content by Tom-s
  1. Tom-s

    The Reference 6SN7 Thread

    That's only until someone notes the GU50 is based on a Telefunken LS50 that is close to the family of FL152 -> EL152, EL153 and EL156. Here's a sample from that family in my collection.
  2. Tom-s

    Bottlehead Amplifier Discussion / Comparison Thread: Crack, SEX & Mainline

    Inspired by the beauty of the Mainline amplifier. I decided to rewire my S3X and lose a stage. Just a single stage, doing it all. For speakers and headphones this time. It now uses the E55L tube (triode connector for a massive 50mA/V transconductance!!) from the Mullard Mitcham factory. This...
  3. Tom-s

    Desirable / collectable vacuum tubes for sale. Updates in first post regularly! Pic heavy.

    I'm selling out some of my tube collection via Head-fi. The start post is up to date. I try to add tubes regularly, so keep an eye. The list of actual tubes is found below and up to date. If you have a question, looking for a specific tube, do ask via PM. Tube testing. Every tube test "good"...
  4. Tom-s

    The 6SN7 Identification Guide

    Last weekend I rebuild the previously pictured self build 1626 Darling amplifier (also found on this forum, sold as Amps and Sound Kenzie) that's doing speaker duty in my study. I rewired the driver section from 12SL7 to 12SN7 (Led bias, CCS@4ma) and started looking around my collection for...
  5. Tom-s

    The 6SN7 Identification Guide

    Thanks for playing along guys, much appreciated! No one's close. Another set of hints. This is the current setup (don't do OPT rolling, hugely impractical as can be seen). The output tubes will teach you the heater voltage. The code seen, the Island of origin. The before told hints the actual...
  6. Tom-s

    The 6SN7 Identification Guide

    Here's a riddle for everyone! Haven't found a picture online of a second specimen, that's why it's here for you! I'm a warm sounding European SN7 and I lack controlled heater warm-up. What am I?
  7. Tom-s

    The Reference 6SN7 Thread

    Height difference is not related with tubes being from different years. Especially in the '20s, '30s and '40s a height difference within a batch was normal. Here's an example of a same date (see Tax sticker), so about the same age, pair of Fivre 76 tubes. Notice the height difference? In this...
  8. Tom-s

    Crack;Bottlehead OTL

    Look at the E80CC/12BH7 modifications thread on the BH forum and all info's there. https://forum.bottlehead.com/index.php?topic=5989.225 As you'll learn from that thread; the 12BH7 wants 7-10mA current to optimize it in Crack. This is done by lowering the R1 resistance on the CCS (see post...
  9. Tom-s

    For 6AS7G tube rollers here .....

    So i opened a window this morning, to cool my study, for a good day of tube rolling! Downstairs i heard the unmistakable sound of shattering glass. It could technically be called "tube rolling"; this one did a false start!...:deadhorse: RIP 1954 - 2020 Death by "tube rolling" off my desk
  10. Tom-s

    Crack;Bottlehead OTL

    I'm not that good with cables. But i do try tube rolling. Meet the grandparents of 12AU7, the first indirectly heated medium mu triodes, type 27. Shown here is a mesh plate version -227- labeled Sonatron (a 1920's company). Based on build/labeling/date code; this pair was made by Sylvania...
  11. Tom-s

    Crack;Bottlehead OTL

    I'm also a very happy @Deyan adapter user! I now have about 10 of them. And all are perfect for my rolling adventures! His 37 / 76 adapter is getting some fine use. I found a General Electric 37 pair in the collection today and opened the boxes for the first time since packing (Date code 43-L0...
  12. Tom-s

    Crack;Bottlehead OTL

    The following should be read with this in mind. I have enough tubes to not have a single clue anymore on how every single one sounds. The driver tubes are Sylvania 76's, that's some sort of grand father version of the 12AU7 and 6SN7/7N7 that became 6J5 and went into a single envelope ->> 6SN7...
  13. Tom-s

    Crack;Bottlehead OTL

    IMHO, while the gains may vary. Rolling a bypass fancy type cap just for the sake of experimentation, to experience how the PS influences the sound, is a good thing to try. Especially with cheap / Russian caps, go ahead. To be honest, i feel you're not the only one here :). But in a good way...
  14. Tom-s

    Schiit Lyr Tube Rollers

    @TK16 Those are Gf1 or Gf2 type builds. They could well be from that date. And yes, those tubes are Bendix Aviation Corps -> Pioneer Eclipse. The original prints on those are red. New from old army supply they have the Bendix boxes with side acces. Edit: And for those with questions about the...
  15. Tom-s

    Schiit Lyr Tube Rollers

    IMHO one should be careful what to advice on. If they were 100%, this would be a "good price". He tested them at 170V plate, -1Vg -> 8.5mA = 100%. Now it's possible they were 5.5mA that was rounded up to 6mA. So two of them have one half that may be 65% or so. And will test as Bad or...
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