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amplifier

  1. david winter

    Sony STR-3800L - Transistor replacements on output board

    Hi, I need to replace the transistors on a Sony STR-3800L output board as both outputs are shorted. The last four transistors in the list differ with the service manual. References in bold were originally installed in this amp, which may be an early specimen (serial at rear is in the 5007xx...
  2. david winter

    Yamaha B-2 - Unstable bias and very tight adjustment range

    Hi, I'm trying to figure out what can cause the -85V supply to drop to -60V when the bias increases up to around 40mV. With no bias, I get the +85V and -85V voltages correct. Adjusting the bias on either channel makes the -85V drop down to -60V. I checked the transistors on the negative rail...
  3. C

    MC250 3v Voltage Spikes One Channel

    Hey all, I had an MC250 brought to me with transformer buzz and severe hum in both channels. I found the 500/200uf multi section filter leaking and after replacing that both buzz and hum are gone. However; I am still getting a nasty voltage spike of 3v dc in the left channel on power on and...
    • CaseyWKC
    • Thread
    • amplifier filter caps mc250 mcintosh mcintosh 250 mcintosh 2500 multi film section caps solid state
    • Replies: 18
    • Forum: McIntosh Audio
  4. C

    Crossover Melt Down - Looking for an Explanation

    Hey all, hope I am posting this in the right place. We've all had our fair share of speaker and amp mishaps I'm sure, but I'm trying to make sense of something that happened the other night. I have a pair of Aerial Acoustic LR5 speakers. I had been driving them with a pair of mono blocked...
    • CaseyWKC
    • Thread
    • amplifier compression crossover damage crown macrotech gain gain sensitivity line sensitivity overdriven
    • Replies: 60
    • Forum: General Audio Discussion
  5. A

    Sony TA-4650 help needed

    Dear all, I inherited a TA-4650 from my dad which had been idle for around 15 years. I used it with great enjoyment for more or less a year before noticing one of the channels was sounding more silent than the other. The difference wasn’t huge, but it was perceptible. Given the reputation of...
  6. A

    KRELL KST-100 power issue

    Hi everyone Got a used Krell KST-100 a few days ago that was playing fine when I listened to it before I bought it. I connected it today to a digital DAC with premplifier output. I turned the Krell on. Played for about 10 minutes. Then the home circuit breaker went off. When I reset the...
  7. W

    Recapping a SAE 2600

    Does anyone have a service manual for a SAE 2600 ? I have the schematics but am looking for the service manual.
  8. N

    Help Troubleshoot Issues With Sony TA-AX390

    Hi AK - This is my first post so please let me know if there's anything missing or if it needs to go in a different section of the forum. I picked up a Sony TA-AX390 integrated stereo amplifier last spring and have had it for a few months now. I got it for a good deal alongside a separate tuner...
    • nsdigirolamo
    • Thread
    • amp amplifier help integrated amp integrated amp help sony sony ta-ax390 ta-ax390
    • Replies: 2
    • Forum: Solid State
  9. maskof

    Advice Needed: Marantz 2385

    Hey everyone, I hope you’re all doing well. I’m a bit hesitant about getting this Marantz 2385 amplifier. I’m still a fan of Sansui and Pioneer, so I’m unsure. Has anyone here tried this monster receiver? How does it sound, and what’s the usual price range? I found one for $1,500 in mint...
  10. wmac

    Sansui AU-11000 new project

    I just received the Sansui Au-11000 beautiful Amplifier, which I intend to restore. Below is a picture of it I was so happy until I opened it, then my disappointment, this must be one of the first units produced. If you look at a similar AU-11000 or Au-9900, all of them have connectors to...
  11. S

    Need Help choosing receiver

    Hello, I could use the support of everyone here. I have a Rotel RSX – 1067 receiver, which runs a five channel stereo system in my main viewing/living room at my home. There are two powered quad front speakers, two quad passive rear speakers, a polk center speaker, and a separate zone running...
  12. T

    Comparing Sony TA-2650, harman/kardon PM640 and Beomaster 1900

    Thought I write couple of lines how these three compare to me. As it's what I have at home now and been working on these as a new hobby kind of. Setup: Source: MXN10 and RME Babyface Pro Speakers: Beovox S45-2 (rebuilt filters, inside cabling and added SpeakOn connectors) Room: fairly small so...
  13. david winter

    Sony TA-1130 - Very early serial ?

    Hi, Out of curiosity, I'm about to service a Sony TA-1130 which seems to have a rather early serial: 550008. The chassis also shows a sticker with 00374 stamped on it. Is this one of the very first units to roll off the production line, or are there lower serial numbers for this model ?
  14. N

    Yamaha rx-a 1050 convert to power amp

    hi all first post here so please dont judge :) So im trying to convert a motherboard failed yamaha avr to a power amp just by using its transformer, amp boards and speaker terminal board ?( dont know the name of this board) all advise comes in handy . First question can i connect line in signal...
    • nikke92
    • Thread
    • amplifier avr diy power power amp power amplifier yamaha
    • Replies: 44
    • Forum: DIY
  15. zastin17

    Marantz 4140. Hard Clipping/Chirping at near max output, but only in 2x Channel bridge mode.

    I have had this wonderful old amplfiier for around 8 years. I got it completely factory, and somebody shorted out the lamp circuit. Easy fix luckily!! Worked great after clearing the short. The entire time I've owned the amp, it has had this strange behavior when I set it to 4x channel bridge...
    • zastin17
    • Thread
    • 2 channel 2270 4 channel 4140 amplifier bridge clipping marantz
    • Replies: 0
    • Forum: Marantz Audio
  16. david winter

    Kenwood KA-5002 - Correct schematic (or compilation of known variants) ?

    Hi, I have an early KA-5002 (serial 250498) which doesn't match the two schematics that I have. I noticed the following differences : - A completely different protection board under the chassis: smaller, no ref, only 4 transistors (of which two 2SC1213, one 2SC883 and one 2SA537A). No schematic...
  17. T

    Curtis Mathes HA-235

    Hi! I'm a librarian in Dallas, I am looking for a service manual for this amp. I can't seem to find it in the Sam's Photofacts Index and I have a patron who has had this piece for a while and wants to repair it. Any help is appreciated!
  18. maskof

    Advice Needed: Marantz 4300 for €800 – Worth It?

    Hello everyone, I found a Marantz 4300 Stereo and Quadradial Receiver. The owner told me it’s in good condition, and the price is €800. Before I make any commitment, do you think it’s a good piece to collect and worth giving a try? I know it’s a Quadradial Receiver, but is the price reasonable...
  19. S

    Amp and tuner or reciever

    I am currently looking at the Yamaha A-S701 with a NAD C427 tuner vs. Yamaha R-N800A. My concern is in the quality of the tuner in the reciever. I miss the 70's and would love my old school stuff back. I wish money wasn't a issue but would like to stay under 2K. I could really use unbiased...
  20. Hollow_Man

    Technics SH 3434 audioscope: Problem with wave form

    Hello I have a Technics SH-3434 audioscope that has a fault in the wave form The horizontal line should cover the entire width of the screen but in my equipment it is compressed When I send a constant frequency the wave is compressed in parts and at the middle point it breaks I...
  21. JHint

    Need help - bias on vintage amplifier SAE Mark IV DM

    Hello amazing community, I’m posting today with a request for help with my SAE Mark IV DM Amplifier - Won at an auction with the matching pre-amp and a dead right channel. The dead channel was solved by identifying FIVE of the eight fuse connectors being loose or broken, and I replaced all the...
    • JHint
    • Thread
    • amplifier sae solid state
    • Replies: 7
    • Forum: Solid State
  22. F

    Balance control on stereo amplifier does not work. Adjusting the volume changes the balance.

    I recently bought a second-hand Mitsubishi DA-U530 integrated stereo amplifier with a broken balance control. Adjusting the balance to the left produces crackling sounds in the right channel but does not change the output power of either channel (as indicated on the amplifier), except for it...
    • FaultyVibes
    • Thread
    • amplifier balance da-u520 mitsubishi stereo volume
    • Replies: 7
    • Forum: DIY
  23. electrotek

    Onkyo A-9130 Volume Increase Causes Protection

    Hi legends! I recently acquired a 5 year old Onkyo A-9130 amp from a first-time owner who found it would cut out (assumably protection circuit) after the volume reached above about 10 o'clock (1/3rd power) if, and only if, music ("input") is playing. However, using headphones does not cause the...
    • electrotek
    • Thread
    • a-9130 amp amplifier onkyo power protection circuit
    • Replies: 0
    • Forum: Solid State
  24. maskof

    Looking for Luxman M-07 service manual and schematics.

    Hello everyone , I found this Luxman set, which includes: LUXMAN M-07: Stereo power amplifier LUXMAN DA-07: D/A converter LUXMAN C-06: Control amplifier However, my concern is that I couldn’t find any manuals for them, especially for the LUXMAN M-07. Does anyone here have the service manual...
  25. Lamar

    Favorite era of pieces shown

    Given the pieces within the eras shown, which era would you say is your favorite? 60's Late Sansui 3000A '68 Sansui 3300 '69 McIntosh 1700 '68 70's Early Sansui AU 777A '70 Sansui 210 '72 Sansui Seven X 2 '74 Sansui Eight Deluxe '74 70's Mid Sansui AU-11000 '76 Sansui 881 '75 Harman Kardon...
    • Lamar
    • Thread
    • amplifier krell mcintosh: pioneer realistic receiver sansui solid state sony speakers
    • Replies: 22
    • Forum: General Audio Discussion
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