John Warren

Here's an example of using a distortion analyzer, one channel is not behaving. The trouble channel will output 5VRMS with 1%THD. A listening test alone would not catch this given 5VRMS can be quite loud and <1%THD isn't terrible for a tube amp. It will show up in the tube pin voltages however as a significant departure from SM requirements.

Recently completed 240. Was in rough shape. Kept the transformers, boards, pots and switches and bottom chassis cover, just about everything else replaced. Sometime in its history the original films were replaced with Multicaps. Other past modifications performed on it caused addition headaches as well. For those of you considering restoring your MC-XX or MC-2XX the service manuals provide expected DC voltages at each tube socket pin, no signal applied at the inputs. If you do not have access to a distortion analyzer, rating the voltages with a Fluke or bench top DMM and writing them down is the next best thing and, if there's significant deviations, the %THD will suffer. Presuming they're within the ranges identified and your tubes are in reasonable condition, your amp should perform with low distortion.

This forum was the first I migrated to after giving up on Usenet. The unmoderated rec.audio newsgroups became toxic, flame wars. Every thread degraded to a shouting match.

He's looking for work? Also, not all cabinet shops do veneer work, they source it to outside suppliers. Does your bud do his own veneering? Does he know how to match veneers or source the right stuff? Reason why I'm asking is I've had issues with suppliers I've worked with in the past. They're used to making kitchen cabinets but have little appreciation for the details needed for "structural" loudspeaker enclosures.

Mineral spirits or Turpentine will work well. Both are very pungent, but Turp isn't as toxic.

Home entertainment setups w/large screens, cable TV interconnects, active subwoofers, and main power amps (2, 4 and 6 channel) can get noisy if 3-prong power cords from various components are plugged into different wall sockets. The Jensen transformers break loops that can occur from this sort of thing. They're broad bandwidth, low distortion, work well.

The $1 Paypal "test" payment has you thinking this is a scam? If the $ was sent using Zelle, what's the problem?

I would agree, the K33E is a rugged driver and, if it's damaged, can be repaired. Albeit how easily in Germany I can't say but given it's the only country in EU where audio is taken seriously there's probably a source for repair.

And, for the record, my collection of rare vintage drivers with coil rub includes University, EV, Bozak, Emilar and a few super rare Japanese drivers. Also in the junk woofer pile, Ohm, Advent, KLH, Sony, McIntosh, AR and Technics sourced.

Why? Vintage drivers were designed for a 10-20W tube amp. A 35W rating isn't RMS either, it's "peak" or whatever the supplier identified it to be. In RMS ratings it's much lower. Failure is always mechanical damage to moving assembly before the voice coil opens, the coil rubs. For the Klipschorn bass unit there's the K33E or you can go down the path of sourcing rare, niche, vintage drivers that will have high probability of failure and, should they fail, become conversation pieces because a recone is impossible.

I stated it was the best sheet metal basket driver ever made. I did not say it sounds very good.

Nice!

On the subject of Alnico magnet, musical instrument loudspeakers, Jensen 15PLL is the best sheet metal basket driver ever made.

Example from McGee, 1964. Utah at $35/pr. In 1964 $1 is equal to $10 today, so $350/pair. Weber's charging $500/pr!

And remember, when you see "hand made" just what are they getting at? Even at JBL, I saw many, many drivers assembled by hand. Production campaigns of 250, 500 and 1000 pieces/run had alot of hand work.