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  1. 9

    Help requested with NE5532 headphone amplifier.

    Okay, is the "pop" upon inserting the headphones into the output jack when the amplifier is on normal as well? I've come to understand that, depending on the output capacitor, turn on thump (and possibly turn off thump) is unavoidable but I wouldn't have thought that there would be possible...
  2. 9

    Help requested with NE5532 headphone amplifier.

    I've recently built this hybrid subminiature tube/op amp headphone amplifier and I've noticed that it delivers mighty thump through the headphones on power on. I then decided to power the amplifier on first and *then* insert the headphones but I still received quite a large "pop" upon inserting...
  3. 9

    Could someone help me identify these tubes?

    Okay, so it seems that both the "Mullard" and "United National" tubes are RFT? I had a feeling that they were of the same manufacture but the fact that one had one getter support whereas the other one had two kind of threw me. The reason I had a question about the Mazda tube is that it has the...
  4. 9

    Could someone help me identify these tubes?

    I've had these European 12 series tubes in my collection for quite some time but even after comparing them against European tubes that I own I cannot determine who made them. If anyone could give me any ideas or clues as to who may have produced them I would greatly appreciate it. Thank you...
  5. 9

    Attempting to create a tube amplifer output stage.

    I have one regenerative receiver that I have already built and another that I will build soon that I would like to build a companion tube amplifier for. My design criteria is that I would like to power the amplifier entirely off of batteries for the sake of portability. I do not need for this...
  6. 9

    Attempting to sort out a battery powered tube amplifier

    So, in order for this switching business to really work you'd need to not only switch between the plate of V3 receiving signal from the grid of the 1st or 2nd 1T4 as well as break and make the connection respectively from the plate of the 1st 1T4 to the grid of the second 1T4? Don't worry. I...
  7. 9

    Small footprint headphone amplifier?

    The question is how many of these designs actually use the tubes for something other than a mere unity gain buffer? I've read a few write ups showing that quite a few of the hybrid designs on the markets use the tubes more for decoration than for any gain in the circuit.
  8. 9

    Attempting to sort out a battery powered tube amplifier

    I recently e-mailed the designer of this circuit and he clarified to me that the switch selects either the plate of V1 or the plate of V2 to be connected to the grid of V3. The plates of V1 and V2 are never shorted together at any time. I'm still absolutely baffled as to why either inserted the...
  9. 9

    Are low voltage tube circuits possible?

    Lately I've been trying to see if it is at all possible to create some sort of low voltage AF amplifier. It doesn't even need to be particularly hi-fi. I'm just looking for something that will give me an entirely tube based amplifier that will amplify either a line level input, an input from a...
  10. 9

    Small footprint headphone amplifier?

    Hello, I was wondering what options were out there for vacuum tube based headphone amplifiers. One of the qualifications that I have is that it needs to be small in size and also have tubes that are of common or at least relatively common type so that various brands may be trialed in the...
  11. 9

    Attempting to sort out a battery powered tube amplifier

    Right, 1/8" jacks with internal switches! Thank you for reminding me of that. Yes, the B battery is a string of 9V batteries. I've never heard of capacitors across battery supplies. What does doing this try and achieve? Does it matter if the capacitor is electrolytic or film? I'm still a bit...
  12. 9

    Attempting to sort out a battery powered tube amplifier

    I have been finishing up an amplifier that I have built from a kit. It's a relatively simple battery tube amplified based around a 3S4 final amplifier and a 1T4 preamp. It was built from a kit and so I have included photos showing the schematic as well as the parts list. The amplifier works well...
  13. 9

    Negative feedback for 928GTS

    @Dadbeh A person had messaged me a while ago showing interest in the table but said that they needed to move something along before they could purchase the table I had on offer. When other people, yourself included, had started to show interest I had a moment where I thought "I really should...
  14. 9

    Help needed eliminating "pop" noise in audio output of radio

    Is there a way of shunting this to ground through relatively high value resistors to ground on the output of the audio? Would a zener diode work or would I just end up running into issues with distortion?
  15. 9

    Help needed eliminating "pop" noise in audio output of radio

    I've recently purchased an XHDATA D-808 portable shortwave receiver. This receiver, like a few others out there, uses the Silicon Labs si4735 chipset as the basis for its receiver section. An issue that I am trying to solve is a loud "pop" heard through the headphones whenever the mode of the...
  16. 9

    RIP MikE

    Rest in peace MikE. Wishing strength and peace to his family and friends.
  17. 9

    Looking for a small tube amplifier

    I've decided to move my audio equipment from my basement up into a smaller room and so I'm looking for a tube amplifier that has a small foot print as I would like to keep things compact. The room itself is about 10' x 10' at most. I'm using a pair of Voice of Music Model 91 speakers but I am...
  18. 9

    Tube phono preamp opinions

    I'm looking to add a tube phono preamp to my system and I'm having trouble figuring out which direction I should go. My main amplifiers are a pair of Wurlitzer 6420 mono blocks. Seeing as how they have no volume control I was looking to see what tube phono preamps are out there with volume...
  19. 9

    R.I.P. George Grand aka Toasted Almond

    I bought a Sony tape deck from George and he was gracious enough to ship it to me even though his ad stated that shipping was not available. From reading all of the stories and sentiments shared here it is clear that he was an extraordinary gentleman. May he be resting in peace.
  20. 9

    Recommended McIntosh restoration service?

    I found a pair of MC60's and an MX-110 tuner recently and I'd like to have them gone through. They're not in terrible shape but the chrome plating on the MC's will more than likely need to be redone as some corrosion has gotten to it. I was wondering who you folks would recommend to do a...
  21. 9

    Nikko preamplifier transistor source?

    Hello, My friend has a Nikko integrated that needs a new set of preamp transistors. They are of types BC 310, BC 311 and BC 312. He'd like to replace them with original units rather than equivalents. Does anyone know where we could source these transistors?
  22. 9

    Help needed with Aiwa auto stop mechanism

    Here are some more photos of the mechanism: http://i.imgur.com/rVGRzwK.jpg http://i.imgur.com/PEitAdz.jpg http://i.imgur.com/FRhvzOe.jpg http://i.imgur.com/rgVyGKt.jpg http://i.imgur.com/lfHIRHo.jpg http://i.imgur.com/3d8qYVB.jpg http://i.imgur.com/TTsD2ss.jpg...
  23. 9

    Help needed with Aiwa auto stop mechanism

    I'm nearly done with cleaning and rebelting my TPR-300A but I am rather confused by the auto stop mechanism. I was wondering why, upon reassembly, the tape deck would not function nor would the amplifier come online. Upon doing some basic voltage tracing I found that the leaf switch that turned...
  24. 9

    An electrical marvel.

    It reminds me a bit of city skyscrapers poking through the clouds. Good thought. If the inside smelled like "Fresh Spring Breeze"...
  25. 9

    An electrical marvel.

    People say that Sony products are reliable and here is another example for your consideration. I picked up this STR-AV270 for use in my studio as a simple monitor amplifier. It looked a bit dusty inside. I figured that I would need to give it a good cleaning and so I took off the cover to get a...
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