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Get a load of the wiring job.I do like the creativity he used in places and the Russian silver micas but the resistors are not what you use in an amp this expensive.Such a bargain lol.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
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Good god what a dog's breakfast that thing is. The soldering is a joke, and gluing components to the chassis... Meh, I've done it but I won't do it again. I had a large filter cap I glued to the chassis of a Grundig radio because I didn't have a suitable clamp. Worked fine for 10 years, then came unglued and shorted against the chassis.
But seriously, $7500 for something so sloppily rebuilt is just a joke. There really does seem to be a lot of builders out there suffering from the Dunning-Kruger effect.
I think I'd take a nice, minty MC240 gone over by Terry DeWick, thank you.
Hi, what ever the circuit is I don't know. I put my mouse on the picture of the innards and blew it up. Those solder joints look like Otis Campbell from Mayberry did the wiring while in his cell.
The splattered paint look is something maybe reserved for something in the future you'd see in Absolute Sound, with the price tag to match.....Mark Korda
What's up with those coils of wires??
At such a bargain I should sell my stuff and buy maybe?
I had the Sherwood hookup up for an ENITRE day. Then I had to break it down to paint the room and entire house. But it was a good hour of listening!!!! That really is a wonderful stereo.
charles
Magnavox used those to prevent VHF parasitic oscillations. Look in any transmitter that uses parallel connected output tubes and you'll see 'em, usually using a large carbon resistor as the winding form. If you DON'T use them when you parallel tubes, you may get some strange behavior...
Charlie
Those coils are made up to act as small inductors because when you wind wire like that,it creates inductance and that is used for various functions.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Wouldn't it be more accurate to buy a coil of exact known value.
I know the formulas to calculate inductance but purchased coils always seem more "accurate" than a good home brew.
Maybe I should make my own capacitors - ah!
I've been eyeing a Marantz 250M for restoration. Do you do those?
charles
Not really because many times you can't find the values or they may not be that critical.The 5 or 6 turns of solid wire was a very common inductor and
it's better to make your own.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
than an MC60. Yeah, sure.
He says they are 50 watts per and then he recommends 95 db speakers as a minimum? With 50 per you should not even have to worry about the sensitivity of your speakers.
"With 50 per you should not even have to worry about the sensitivity of your speakers."Vinnie, there are quite a few "Watt Hog" speakers out there, for which 50 WPC would prove insufficient.
Paul Joppa's 102 dB. rule is useful in matching amps to speakers. "Joppa's Rule" states that for "average" volume listening spaces, an amp/speaker combo should be capable of 102 dB. SPL peaks at a 1 M. distance.
Where things can become highly problematic is the derating sometimes necessary when commercial speakers are mated to tube power amps. A nominally 4 ohm speaker whose claimed sensitivity for 2.83 V of drive is 89 dB. is "really" 86 dB. sensitive, as 2.83 V. into 4 ohms is 2 W., not 1 W. Another "gotcha" is impedance curve. Large dips in the curve, particularly in the deep bass, require reducing the nominal impedance and allowing for the consequent reduced sensitivity.
Big Thiel speakers, with their dips down to 1 ohm, are (IMO) very poor candidates for mating to tube amps. The power O/P needed is less important than a very large damping factor. BTW, those big Thiels will wreck mass market SS equipment, should it be connected up.
Eli D.
Edits: 08/15/16
with even typical dynamics the peak to RMS ratio of Recordings are 15-18dB. I just fired up my B&K 2270 sound analyzer and placed the microphone a meter away.... talking at a normal voice level - like a telephone call yields 91dB peak - Dropping my mouse onto its pad from 4 inches generates 101.81dB peak levels (1 meter away) This is not a snare rim hit! dropping my mouse onto the desk surface without a pad from 4 inches gives a peak level of 113.6dB! a hand clap gives me 130dB peak at 1 meter
I remember taking the sound meter to a Jazz Club (seats about 50 people) 10 years ago and measuring the concert from the back of the house. Piano topped 110dB peaks, snare topped 120dB and even the trumpet was over 105dB. Now the maximum RMS levels (A weighted) rarely topped 100dB. Live music impulsive sounds typically have a 24-30 dB crest factor (the Ratio of the Peak to the RMS values) - most (almost ALL) recordings use limiters that drop this to 15dB or so. This is the SHAME of the music and recording world.
IMO a system that can't reproduce over 112dB PEAKS risks clipping the amplifier on Dynamic music transients. I have measured 112dB peaks from my listening seat from my very inefficient MMG (83dB/watt@ 1 meter) loudspeakers driven by amplifiers that clip at about 1000 Watts. By this standard an 93dB/W@ 1 meter speaker would need a 100 Watt power amplifier.
"The hardest thing of all is to find a black cat in a dark room, especially if there is no cat" - Confucius
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