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Chip Amps Amplifiers based on integrated circuits

Modulus-86  build thread
Modulus-86  build thread
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Old 6th January 2018, 05:32 AM   #3761
anatech is offline anatech  Canada
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Hi Johnny2Bad,
Mr. Tanner was very displeased with me at the time. Let's just say I know those amps better than you ever could. I fixed many and know exactly what they did right, and what they did wrong. I saw many that blew up on their own operating into 8 ohm loads at sane levels.

Did you have any of those face plates tear or come right off in the road case? How about dead power switches? Did they sound good when first turned on by chance? I know why they didn't, just so you don't answer that question incorrectly.

As bad as those amplifiers were, their later products became well engineered with the arrival of S.T. I like the current products, so I'm not on a hate Bryston trip. I'm just telling you the truth.

-Chris
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Old 6th January 2018, 05:56 AM   #3762
Johnny2Bad is offline Johnny2Bad  Canada
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Originally Posted by anatech View Post
Hi Johnny2Bad,
If you're talking about the original 4B, it was anything but bulletproof! Holy crap, it was made with the least expensive parts you could buy! I know because I worked on them. I reverse engineered that model because it was a secret at the time. I am more than a little familiar with those.

However, the current product looks good and sounds much, much better. One day I might see inside one of those.

-Chris
Not sure what your clients were doing with them, we sold 20~30 per year and never saw a single one come back for service. I'm referring to the 2nd iteration of the 2/3/4B, the ones sold in the late 70's. No power switch failures that i'm aware of. Some bent rackmount ears, no breaks. I don't know about "least expensive parts you could buy" but the retail prices were quite reasonable ($450/800/1200).

Yes, they needed a warm-up period to settle in sound wise. The best sounding of the series was the 2B, the 3B the worst.
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Old 6th January 2018, 04:37 PM   #3763
anatech is offline anatech  Canada
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The 3B was nearly identical to the 4B. The only changes are in the output stage, so they will sound the same. As for not seeing them back, of course not. Bryston was shipping output modules that the customer would change themselves.

I don't know how you guys could miss seeing those very common problems, they were common enough for me to know there was a problem. The reason they sounded terrible before they got to the bloody hot range is that the bias control circuit was garbage. Poor design and the amp shouldn't have seen the light of day until that was fixed.

When roading these amps, the chassis was too thin, so rack mounted gear would eventually have a tear in the metal along the bottom, front edge. The power switches were not up to the turn on surge (no soft start!), so they would fail for sure at some point unless you left them on 24/7. Without any form of protection network, this was an extremely irresponsible position to take. So the fix for these problems? Bryston told users to leave the equipment on all the time as the amp was designed to "take it". This was of course not true at all, but it ended complaints about power switches and crappy sound during warm-up.

There is only one reason Bryston didn't go out of business. They hid the problems they did have, and the fact that parts will take all kinds of abuse before dying. Cheap parts. If you looked up all these parts they used in the ELectrosonic catalogue, you would see they used a lot of Philips parts (cheap garbage), although the outputs and drivers were Motorola. They had them remarked to "Bryston numbers" to thwart external service people from repairing these. The TO-220 drivers were modified to have longer leads than normal as well.

I have often wondered how good I could make an original 4B sound by using better parts and matching some transistors. I've already looked at the design and know roughly what I want to change. I think I would have a stab at fixing the bias current control circuit as it doesn't have enough authority the way it is now. A soft start circuit and speaker protection would also need to go in. It's already pretty tight in that chassis!

Anyway, the 4B was a low quality amplifier that didn't sound very good compared to other amplifiers in it's power class. It was not reliable compared to other products either. I am extremely happy that they turned that trend around and are now making something they can be proud of.

It blows me away that you didn't recognise the problems with it. I guess you were well insulated from the user market after the sale. My dealings were mostly with companies that bought the product direct. You wouldn't have seen that volume of amplifiers or the use these amplifier were in. One company went back to the BGW 750C amps they had because Bryston product was blowing up, falling apart and cooking all the other gear in the rack. The real 4B is obviously something you are protecting, or you simply didn't see the service side, which Bryston worked hard to keep out of the public view.

One company paid me to reverse engineer the 4B, even with Bryston interfering and objecting to outside involvement. They had had enough of the failures to the point where I was brought in as an objective third party. My diagram matched the one Bryston released a short time later. There are a few details about their claims that you don't know, but I'm not going to drag all that out into the open. Let's just say that some of their advertising claims could not be supported once their facility had been examined ( I was in a tour with a group).

I sure wish you were technical and had an opportunity to work on one. You would have an entirely different opinion compared to what you are saying right now. But if there is one thing I would leave others with it's this. Do not buy an original 4B. It is an incident waiting to happen and should never have been sold.

-Chris
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Old 6th January 2018, 07:17 PM   #3764
BrianL is online now BrianL  United States
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I'm not sure what all this has to do with Neurochrome's new amp design.
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Old 6th January 2018, 08:09 PM   #3765
sq225917 is offline sq225917  United Kingdom
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It makes us love the quality engineering all the more...
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Old 6th January 2018, 11:15 PM   #3766
anatech is offline anatech  Canada
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Hi Brian,
Absolutely nothing. A claim was made that I couldn't let stand as it was inaccurate. I had planned to drop the subject in fact.

-Chris
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