Author Archives: retrovoltage

The New Stewart-Warner Series 900 Radio

This Consolette Ensemble combining Stewart-Warner Table Cabinet Receiver with the New Stewart-Warner Dyphonic Reproducer, an arresting value at $113 (less tubes). Radio Retailing, April 1929

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Yamaha B-2X Check-Up and Adjustment

I recently had this Yamaha B-2X through the shop. It’s a massive beast of a power amplifier from the late ’80s, delivering up  to 170W per channel with 0.002% THD. Being somewhat more recent, this one just needed a quick … Continue reading

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Extracting Screenshots from the HP 3585A Spectrum Analyzer

I’ve posted a few times about my HP 3585A spectrum analyzers over the past several months, and after chipping away at the problem I’ve finally solved the screenshots issue! It boiled down to a bad GPIB cable for my National … Continue reading

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Accuphase C-200 Professional Pre-Amp Full Overhaul

When Kenwood’s engineers left to form Kensonic, they really brought their A-game, and this Accuphase C-200 pre-amp is no exception. It’s a mammoth device, built with exceptional attention to detail and top of the line components throughout. The owner reported … Continue reading

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Harmony H400 Tube Guitar Amplifier Repair

I recently had another Harmony amplifier, the  H400, through the shop for an overhaul. It’s owner, who previously sent me a Harmony H500 for service as well, took it to a local tech but wasn’t satisfied with the repair so … Continue reading

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Telefunken Bajazzo Sport 201 Transistor Radio

I don’t typically service portable transistor radios, but I make an occasional exception for something especially unique or interesting. The Telefunken Bajazzo Sport 201 is no exception – it’s a high end piece of German engineering, a great performer with … Continue reading

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Sony TA-5650 Full Re-Cap and Adjustment

I recently got to work on another of the Sony VFET line of integrated amplifiers, the Sony TA-5650. I’ve had one through the shop previously, and this one came in for the same service. It came in running fine – … Continue reading

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Fun with the HP 3585A Spectrum Analyzer

I spent some time playing around with one of my HP 3585A spectrum analyzers over the weekend to get a feel for its capabilities. While it’s only good from 20 Hz – 40 MHz, it’s a very capable tool within … Continue reading

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1960 Grundig SO191 Stereo Hi-Fi Console Repair

This stunning piece of late mid-century modern German engineering, the iconic Grundig SO 191, recently came through the shop. It’s owner picked it up from an antique shop in nearly pristine cosmetic condition, but with a few electrical issues to … Continue reading

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Bose® 901 Series VI Active Equalizer #199732 Repaired

A first for my shop, I recently worked on a Bose® 901 Series VI Active Equalizer! These are considerably newer than the Series I-IV that typically come through the shop, although they’re still getting to be 25+ years old at … Continue reading

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