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  1. FlaCharlie

    Guess im the guy who brings this back up... (tubes sounding better)

    I don't have any insights or theory about tubes and psycho-acoustics but I do find some of the things you've said about your preamp to be puzzling. Perhaps you or some of the more technically minded participants can comment. I was under the impression that a tube needs to have a load. In the...
  2. FlaCharlie

    Good sounding cheap Chinese tube amps?

    You should rotate your transformers. The PT and OTs should not be oriented in the same way, especially if they are mounted that close.
  3. FlaCharlie

    L Cochrane push pull 6l6 amplifier debug.

    I don't know anything about pricing on the secondary market but I suspect they sell for quite a lot since his amps do seem to have a reputation for sounding good. Many people are familiar with Kevin Davis' Glow in the Dark site which displays numerous amps designed and built by well known...
  4. FlaCharlie

    high res. 9303 schematic needed

    Here's the Beitmans and the Sams. The Sams is in .pdf and can be enlarged to view details.
  5. FlaCharlie

    Build 2A3 or 300B tube amp?

    If you decide to go with the 2A3 another kit to consider is the Analog Ethos Legendarium. @theflattire built one of them a while back and was quite pleased with it. He had previously built one of the Bottlehead amps that also ran 2A3s. Here's his build thread...
  6. FlaCharlie

    Snap, crackle, pop.

    If heat changed the color it would have to be extremely localized for it to change the second color band from orange to black or brown while the first color band remained orange. It seems more likely to me that they are different values. He just needs to do a simple measurement. When you can...
  7. FlaCharlie

    Snap, crackle, pop.

    The pic in post #40 doesn't show the orientation of the 100uf 50v caps very clearly. The gold stripe on the one in the foreground (the negative lead) is clearly visible and the stripe on the other one is not visible. Unless the two pairs of resistors are grounded differently, the two caps...
  8. FlaCharlie

    Zero Zone tube preamp putting out DC?

    So your tech has had this preamp for almost a year now and no progress has been made? The troubleshooting suggestions I made earlier should take maybe half an hour to try. His post (#137) from 11 months ago seems to indicate that the filament winding of the transformer drops from 8v unloaded...
  9. FlaCharlie

    Little Dot Mark II tube headphone amp blowing fuse, help needed please

    Thanks for the clarification. I knew there was a reason they are typically used with sections in parallel and one per channel.
  10. FlaCharlie

    Little Dot Mark II tube headphone amp blowing fuse, help needed please

    I was under the impression that a single 6N7 couldn't be used as a stereo preamp since the cathodes of the two triodes are internally connected and brought out to a single pin. I've seen two used, one per channel, with the two triodes wired in parallel which is what the data sheet specs...
  11. FlaCharlie

    Installed a wifi board (Arylic) - now Tick, tick, tick sound, grrrrrrr!

    I use several Apple Airport Express units to stream via WiFi around my house. If you have an Aux power outlet on the back of your receiver you can plug it in directly. The audio output will need a 1/8" stereo to dual RCA adaptor and then plug the RCAs into your Pioneer. It's also a dual...
  12. FlaCharlie

    inexpensive output transformer.

    Everything you say is correct, of course. Perhaps "rarely" was a bit too simplistic. Maybe I should have said that the lowest notes typically comprise a very low percentage of the total notes played. Lots of variation depending on the type of music though. Lots of what we hear with all...
  13. FlaCharlie

    inexpensive output transformer.

    Keep in mind that the main difference between high quality (expensive) OTs and lesser quality (inexpensive) ones is typically found at the extremes of the frequency range. Yet, in most recorded music there is very little musical information at the extremes. Those who choose OTs based solely on...
  14. FlaCharlie

    FX Audio 6j1 tube preamp - a $31 wonder

    Hard to guess what they mean by that. You would need to take some measurements to figure it out. Could be supply voltage, could be plate voltage but in either case it's not a huge difference from the original. According to the original "Fever" schematic posted earlier in the thread the...
  15. FlaCharlie

    Show us your flea-watts amps!

    I would suggest that you start a new thread to discuss these technical aspects further. It seems to me that this thread is primarily intended to be a simple "show and tell" thread for people to post pics of their flea power amps. The particular design issue you're interested in probably...
  16. FlaCharlie

    Show us your flea-watts amps!

    The only ones I have any experience with are the Meanwells but I'm sure there are numerous other brands too. I'd just buy them from a major electronics supplier, not something you find on eBay or AliExpress. I believe DigiKey has warehouses in Europe too but, if not, other suppliers should...
  17. FlaCharlie

    Show us your flea-watts amps!

    I assume your comments apply to @kurorin 's amp - the one that uses the 71A or 12A as an output tube.
  18. FlaCharlie

    Show us your flea-watts amps!

    No, I've never tried it with output tubes. As far as I know the rule with directly heated tubes is that, since the filament also serves as the "cathode" any bias scheme that involves the filament requires the tubes to be heated separately. I'm sure Jack understands the technical details much...
  19. FlaCharlie

    GloTone Cockeyed Monkey - A Directly Coupled SET

    Yeah, I assume that most of the difference is the 2v higher wall voltage and significantly lower ESR of the film caps. Close enough. Real world listening results under normal operating conditions are the important thing.
  20. FlaCharlie

    GloTone Cockeyed Monkey - A Directly Coupled SET

    Yeah, that's basically what I did except that I added resistance between the rectifiers and the first cap but the results would be the same. There is some discrepancy between my PS schematic and PSUD because my schematic voltages are measured with the variac set to 122v, which is about what...
  21. FlaCharlie

    GloTone Cockeyed Monkey - A Directly Coupled SET

    That's correct. All voltages are measured, not based on a sim like Spice, which I have no idea how to use. I did run a PSUD sim but the results are suspect since the program can't be configured as a Cockeyed Bridge using a tube as a slow start device.
  22. FlaCharlie

    Show us your flea-watts amps!

    Thanks, I found the website. The schematic was somewhat hidden but I also found it so I'm posting it in case others are also curious. The whole design seems rather complex. I'm not very technically oriented but it seems like it shouldn't take so much to drive a 71A or 12A. These tubes are...
  23. FlaCharlie

    Show us your flea-watts amps!

    You're the master of compact design! I'm used to working in tight spaces when restoring vintage amps or modding a circuit in an existing chassis but when I build things myself from scratch I like to have plenty of room.
  24. FlaCharlie

    GloTone Cockeyed Monkey - A Directly Coupled SET

    The current was calculated at idle, not dynamically, if that's what you're asking. It's posted on the schematic. As I understand it, current is essentially constant in a SE amp which is Class A by definition. The DCR of the Hammond 156c plate chokes shown on the schematic are the measured...
  25. FlaCharlie

    Show us your flea-watts amps!

    Here's my latest build, the GloTone Cockeyed Monkey. Details, including schematics, are here: https://www.audiokarma.org/forums/index.php?threads/glotone-cockeyed-monkey-a-directly-coupled-set.1040847/
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