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Hi Folks, Trying to diagnose a noisy (buzz) in a pair of self-powered speakers - LV1020 by Braun. The buzz/noise comes from the midrange and tweeter only. I've replaced a variety of transistors due to other audial artifacts ("popping") which ultimately was traced to the BC157 transistors...

Hi Folks, while transistor substitutions had sometimes been difficult in the past, I'd taken a couple years off from doing restoration work and it seems even fewer through-hole components are available from reputable dealers (Mouser, DigiKey) now. I feel like I've looked up dozens but all are...

Anyone have a suggestion for readily available sub for BC341? I've found several but all are either 20 bucks a piece or NLA. Thanks!

Anyone know a reliable equivalent to the old BAX13 diode? I've searched this forum and others and haven't turned up anything (which is a new experience for me!) Thanks in advance.

Hi Folks, Looking for a little help-- I'd mainly like to get confirmation on an assumption. I have a tube preamp that about 1.5 years ago recapped the electrolytics and replaced the selenium rectifier with silicon diodes. It worked great for most of that time until one night, I accidentally...

Hi Folks. Need some help here-- trying to troubleshoot a pair of powered speakers (schematic attached). Both speakers have been exhibiting thump at turn on and one exhibits some intermittent static after long warm up and this same one consistently exhibits this same static as the cap...

If the Bias Alignment Instructions are as follows (translated from German): "The quiescent current of the output stage is set to 35mA at room temperature and 220V mains supply without signal with R611, R641 at 30mA and R671 at 25mA." Could I expect to halve the current figures for 110V...

Hi Folks, I have a pair of powered speakers- one speaker gets noisy when it's been on for a good 20 minutes at least. When I power down, the noise becomes more consistent as the P/S caps discharge. Would this perhaps indicate that the noisy transistor is in the power supply?

Looking for equivalents for BC157 and BC171 -- I know these are old devices, but I'm not finding much of anything in terms of modern (orderable) replacements. Anyone run into these before? Suggestions? TIA.

Hi folks, Restoring a pair of tri-amped Braun speaker and just got around to replacing two filter caps. The originals have a metal case with positive and negative terminals on top and have a bolt protruding from the bottom of the cap case which is bolted to the chassis/ground. Using the DMM...

Hi Folks. Restoring a pair of internally tri-amped speakers and I've run into an issue I'd like to get some opinions on. The schematic can be found here. The midrange amplifier keeps blowing its 1.25A fuse. Through testing, I found that T634 and T635 were bad. There has been some work on...

Hi Folks, I have a Chord Mojo that I use when on business travel and absolutely love the sound-- both through IEMs and used as the DAC on my main system (components rotate often). Can anyone suggest a DAC with similar audio characteristics that I could use as a permanent part of my main system...

Hi Folks, I have a pair of LV1020 amplified speakers with replacement 12" woofers that appear to be of the car audio variety. I'm looking to begin my search for original replacements (however long it takes) but haven't found the model number and/or manufacturer of the originals. I realize...

Bogen Preamp, schematic attached. FWIW, I've noticed some inconsistencies in the schematic in terms of cap values, etc. I can go into details on the ones I've noticed if that's helpful. This was in original condition when I received it and I never powered it up before recapping it. Typically...

To preface-- I've recapped (and fully restored) dozens of solid state amps with varying topologies. I've learned to do my research and ask questions so I can proceed confidently-- but tubes are a different animal. This is my first tube amp (it's actually an integrated)-- a Heathkit AA-151. I...

I'm trying to fix this for a buddy but am running into some issues. It won't come out of protection and the signal doesn't make it past the pre-outs, which helps isolate the problem area. 1) I can't find any offset adjustment instructions in the manual (found here) 2) I'm tracing signal...

Hi Folks, Recently acquired an integrated amplifier and after pulling and testing the outputs, found a phenomenon I haven't run into before. The left channel's output transistors' gain are on average about twice as high as the right channel. Two things to point out: 1- the voltage...

Hi Folks. After a year layoff, I've moved back to a house, built a new workbench and im ready to get back to my favorite hobby. Restoring these magical sound-producing machines. First up on the new bench: a (very) dirty 2245. The insides appear untouched and both channels play with little...

Hi Friends. I recently acquired a pair of EV Cardinal IV speakers, exceptional condition in blonde Klipschorn cabinets. I realize the crossover is encapsulated in tar-- and the brilliance knobs may have some corrosion. Are there any other considerations to take before firing these old...

I recently performed a recap on a beat up Luxman L110, schematics for the 1st stage/protection/PS board and the 2nd stage/driver board are attached. There have been numerous repairs done on this heavy duty integrated over the years and I need to fix it for a friend. With R703 removed (there...

Hi Folks- recapped one of these beasts and now it wont come out of protection. It's possible one of the pots were inadvertently adjusted during the process as it's a relatively tight space/awkward unit to work on. Looking for nominal offset figure and bias, too if that's available (the SM...

Have a problem folks, and haven't been able to find much in the way of remedies thus far on the Internet. Have a Phillips GA-212 with intermittent issues. I've replaced the belt (was original), and the previous owner replaced the power switch. I also just replaced all 3 lamps in the speed...

I'm sure these photos have made the rounds often, but I haven't seen this particular one before. Very cool. http://imgur.com/wrP02YN

Hi Folks- I'm thinking about embarking on a mission to rewire a Dynaco Stereo 400 power amp that I've been (slowing) working on for a while. It's an absolute nightmare to work on as-is, with solid core wiring and a huge heatsink. The wiring is so rigid it literally suspends the driver...

I have an HH Scott 272 Integrated completely redone (magnificently, I might add) by Craig @ NOSValves. I want to use this as my daily driver (perhaps on a switch opposite a Sansui AU-7500) I have quite a few speakers, including Bose 201 series II (heh) Burhoe Green Ohm Walsh II...