Recent content by handyguy

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    Accuphase A-70 voltage conversion

    Does anyone know if the A-70 supports change in line voltages by easy circuit board/transformer wiring changes? The official Accuphase brochure states it is either 120/230vac (not even 100vac for the normal Japanese line voltage.)
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    New thread on DC offset protection and B&K 200.7

    Thanks for the tips. Yes, not sure about purchasing. There is one (an s2) going for a $1000 near me in like new shape, but, like you said, they are dodgy amplifiers to get involved with.
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    New thread on DC offset protection and B&K 200.7

    Thanks for the warning! Any tips on setting the bias and dc offset? I have the so-called service manual, which is just a few incomplete schematics (not even this model named in it), but no text.
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    Found an exact replacement for the LDR in Mc2255 and other Mac's

    Hi, I'm wondering what the symptoms are of a failing LDR? My MC2255 has a small, random, turn-on pop noises, and I am thinking it might be the LDR's, since I believe the dark resistance decreases over time, from what I have read.
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    New thread on DC offset protection and B&K 200.7

    There are a few different technologies for DC offset protection: Triacs, capacitors, relays (SSD/mechanical). Some say that mechanical relays are subject to total destruction due to arcing upon a DC event.
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    New thread on DC offset protection and B&K 200.7

    How/what did you replace the mosfet with? Just replaced the one?
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    New thread on DC offset protection and B&K 200.7

    Yes, but the factory fuses are 6 amp slow blow, probably not gonna protect from a sudden DC offset when an output transistor blows and goes short.
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    New thread on DC offset protection and B&K 200.7

    Hi, There are many (inexpensive) aftermarket DC protection boards you can buy to cover you if your amp does not happen to have protection. Youtuber xraytonyb has several videos on them. However, you would need 4 of these boards in this case. There are many different designs for these boards...
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    Yamaha NS-1000 driver diffraction reduction

    I believe bad speaker connections are one of the worst, easily fixable culprits. I would go with replacing those first and secondly, some solid speaker stands the place them at the correct height for your seating listening positions.
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    Yamaha NS-1000 driver diffraction reduction

    Although the NS-1000's already have an excellent sound stage/imaging, I believe the anti-defraction pads have slightly improved it.
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    Yamaha NS-1000 driver diffraction reduction

    I am very busy for the next few weeks so I have not had much time to listen. At the moment, they are able to be held on with just tension, but I was planning on using some double sided tape, mainly attached to the driver frames.
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    Yamaha NS-1000 driver diffraction reduction

    I know that there is some worry that sound wave diffraction from the edges of drivers can be of concern. To reduce that on my NS-1000's I cut some wool panels to place over the mid and high drivers. The material is 1/2" natural wool felt and I have attached the laser cut file here if anyone...
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    LDR 144-070 for MC2200/2205

    The next time I have my 2255 on the bench, I'll test the circuits and report back. It's so heavy, I don't like to move (and remove the glass) more than necessary. Thanks!
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    LDR 144-070 for MC2200/2205

    I was trying to further diagnose the thump, as it does not happen on every turn on. It's fairly minor, occurs with the speaker switch off or on, and occurs immediately upon turn on (as the self check counts down). Mostly seems to be the right channel. The bias and dc offset have been checked and...
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    LDR 144-070 for MC2200/2205

    thanks for the update.Wondering if a failing muting ldr might be the cause of the turn on pop on my mc2255? If it's failing to completely mute before the light switches on? I guess I can test that, in circuit?
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