The boards are adapted to as close of input impedance match as possible when ordered (and noted on website). Many boards 210, 201A 202 etc. are very similar but differ in subtle ways because M.C. cartridge designs (even same models) varied in performance, especially in low frequency "equalization" and output level. We at APT tried to keep up with this matter and attempted to calibrate each card to within +/- 1db at 50hz (lows) for specific cartridges, but it was getting too complicated when more different M.C. designs kept coming. 201 or 202, A, B whatever, were often updated with a multi parallel input transistor board (to change impedance, slight gain, against noise parameter, etc.)....Read Full Article
Read Full ArticleVince, the shop owner, has worked as chief technician at KLH/Burwen Research and knows this equipment inside and out. Recently he was asked to possibly update and improve this unit. He modified the click sensor circuit to gain ride the audio ticks to allow easier and less critical "sensitivity" and "threshold" adjustment, so that the unit tolerates a greater range of audio level coming through without false "de-clicking" of audio transients. ...Read Full Article
Read Full ArticleVince used to work for Apt and has developed certain upgrades to increase the reliability, longevity, and also the fidelity of these already remarkable preamps and amplifiers. The APT 1 Amplifier and Apt Preamp upgrade consists of three levels to suit your modification needs. The APT 1 amplifier is a truly advanced product and even by today's standard, a very modern audiophile amplifier design. Some of it's design technology is only now being implemented in fancy name equipment. Seldom are so many of it's clever design tricks for correctly stabilized feed back circuits, optimized impedance matching both at input stage design, power supply and output amplifier circuit have been utilized in total (even compared to fancier products.)...Read Full Article
Read Full ArticleVince used to work for Apt and has developed certain upgrades to increase the reliability, longevity, and also the fidelity of these already remarkable preamps and amplifiers. The Apt Holman Preamp and APT 1 Amplifier upgrades consists of three levels to suit your modification needs.
APT Holman Preamp Upgrade:
Level 1: We repair the obvious faults and clean all controls and switches. We replace any obviously bad capacitors and do only minor upgrades....Read Full Article
My circuit alterations are very neatly done and can be undone if required. The unit in general will be less buzz saw sounding and can be easier to program warm tube overdrive sound into it. Ultimately, the unit will have Voicings which can be made more intense or subtle, i.e. more crank, or more silky overdrive, or cleaner for the Acoustic sound. ADA's engineers and I, about 20 years ago, would swap ideas and the engineer who developed this product apparently later included some of my modification into the MP2. I did this same modification for many serious pro players in the 1980's. The cost is $300.00 which includes all cost of parts and return shipping (parts may be tubes, connectors, or capacitors, about 20 parts maybe installed.)...Read Full Article
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