John Curl's Blowtorch preamplifier part II

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Hi Brad,
I had a 300 for a while and was dubbing vinyl from a decent 'table, arm, and Shure V15.
Naks were very happy machines. There was an update to change the idler wheel for the fast winds to a gear later on. T/U tension was dropped to 35 gr/cm with the gear mod installed. That was valid for "standard mechanism #2". The earlier machines from the 480 and later were, you guessed it, "standard mechanism #1".

-Chris
 
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Hi dvv,
but the end rsult for a regular buyer was still worse on the Nak than on the Sony,
Yes, and that is what makes it such a shame! The gear was capable of truly fantastic performance, but few ever heard it. Every machine we serviced created extremely happy lifelong customers. Similar situation for all CD players, most are not adjusted as well as they can be.
my experience tells me there's a lot of perception here
Mine did too. Then I started servicing them and saw what they could really do. So much for the idea that they were just over-priced! I always wished that Nakamichi had come out with an open reel machine. That would have really upset a lot of people! But Studer & Revox do deserve their reputation. Everything was milled to the proper dimensions needing very little in the way of shims. Contrast that to any Japanese machine where everything is adjustable to make up for loose manufacturing tolerances. With Tascam I was always shimming multiple things to get it in alignment.
was a model quite below the DraGON STANDARDS
The Dragon wasn't that great, really. The 1000ZXL was the peak of performance, and the 1000ZXL limited really did have gold plating in the transport. Given a choice between the Dragon and the CR-7, I'd go with the CR-7 I think. That's a BX-300 with auto-calibration.
Ever hear their car product? I still have a TD-700 (nice machine!), and maybe a locked TD-1200 MKII somewhere around here. That had a great FM tuner. Cassette was perfect on that one.

-Chris
 
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Hi ticknpop,
20 years of 5210/5087, steel leaded metal film resistors, aluminum electrolytic interstage coupling capacitors (often 4 to 6 in series through the signal path), a single pair of 7815-24/7915-24 regulators for an entire preamp or processor, ceramic hf bypass caps, standard diode bridges, - or it's surface mount equivalent - all the ingredients for mid-fi at it's best
Bryston was complete garbage until they hired a real engineer. The stuff failed all right, they kept it quiet with the 20 year warranty. They simply included the costs of repairing a percentage of equipment with the selling price.

There isn't much wrong with the 2N5087 and 2N5210. They didn't match them for one, and surrounded the transistors with Philips components from Electrosonic. Open a 4B and an Electrosonic catalog from the same time period. You can find each part they used. No soft start and a defective bias control circuit meant that you had to leave the amp on all the time, or replace power switches and wait a 1/2 hour for the outputs to become biased near where they would end up. They were class C for a while before the bias came up. Junk.

I hear they make real amplifiers these days.

-Chris
 
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Hi ticknpop,

Bryston was complete garbage until they hired a real engineer. The stuff failed all right, they kept it quiet with the 20 year warranty. They simply included the costs of repairing a percentage of equipment with the selling price.

There isn't much wrong with the 2N5087 and 2N5210. They didn't match them for one, and surrounded the transistors with Philips components from Electrosonic. Open a 4B and an Electrosonic catalog from the same time period. You can find each part they used. No soft start and a defective bias control circuit meant that you had to leave the amp on all the time, or replace power switches and wait a 1/2 hour for the outputs to become biased near where they would end up. They were class C for a while before the bias came up. Junk.

I hear they make real amplifiers these days.

-Chris
One of their claims to fame at least in the old days was their complex composite output stages, which appear in simulation to be the devil to compensate.

Funny story about the Brystons. Harman had a hand in equipping a Cinerama theater in LA, and used the "second-label" Proceed amps from Madrigal. I never heard one or saw inside one, nor knew who did the design, but they were probably o.k.

Someone with golden ears heard the system and complained that it sounded awful. Harman wound up replacing the amps with Brystons and it made the guy breathe a sign of relief. Of course he was told beforehand what had changed.

This was quite a few years ago.
 
One of their claims to fame at least in the old days was their complex composite output stages, which appear in simulation to be the devil to compensate.

They actually oscillated so badly they toasted the power supply capacitors. Their solution was get a specially made capacitor that took the heat without quick failures. A lesson in why you need a wideband scope or rf probe to really check circuit stability.
 
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