John Curl's Blowtorch preamplifier part II

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#90,562
Hi dvv,
Yes, exactly. I think the 1180DC adds a transistor connected as a current source to the output of the RIAA amplifier. I also have an 1180DC - on my bench. I was spoiled with the 300DC. I'm planning on going over the preamp section to improve it as well. The amplifier section was already done earlier in time.

I'm not certain the HK will sound better. Maybe for raw power, but the 300DC is packed with tricks that really elevate it's performance. If you haven't already, go over that schematic. It does sound a little bit better than the 170DC does after working it over. One big benefit is the regulated DC for the voltage amp stages, each separate from the other. I hope you can find one of these amplifiers in your travels and buy it.

I also have an SC-9 preamp that I like even better than the 3650, but I doubt I could hear the difference between them. I like the gold colour of this preamp.

If I were to design and sell preamplifiers, I would recreate the SC-9 except with relays and a slightly different internal layout. Improved power supplies and better shielding might ... might increase the S/N ratio. I'd lose the second tape deck circuitry and retain the phono amplifier sections pretty much as they are now. The surface noise off an LP is much greater than the noise from the preamplifier.

The 3250 is also an extremely nice preamplifier. Looks good too, a lot like an 1180DC - I wonder why that might be???

-Chris 🙂
 
#90,563
jan.didden said:
What I find interesting in this paper is the notion that it is important whether you can expect a 'reasonable' customer to realize that a claim is not a literally true claim but just an unsubstantiated piece of puffery.

But is that in itself reasonable? To remain with audio, if I make an outlandish claim for genetically engineered cables, can we expect the average customer to see through it as puffery? Many posts here in the past make me doubt that.

Jan
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In legal cases, a judgment must be reached. There are easy cases and hard cases.

In easy cases, its very clear what the law is and what the facts are, and the judgement is arrived at through logical deduction.

In hard cases, the law and the facts are more vague. In that event what actually happens is that judge uses his or her moral intuition to sense which side should win, then constructs a story out of the law and the facts to make it so. Now, judges and lawyers probably take strong exception to what I just said, but psychologists who study morality and moral reasoning can make a very strong case that what I said is how it actually works deep down under the hood. Judges don't realize that's what they are doing because they only know what 5% of their brains are doing (conscious awareness), the rest is hidden, and its the hidden part that is making the real decision when the law and the facts are vague. The constructed story has takes appearance of logic, but it constructed after the decision has already been reached. That's how different judges can reach different decisions given the same facts and same laws.

Therefore, what is puffery and what is false advertising depends on easy case or hard case, and on the particular judge.
 
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#90,564
Markw4 said:
In legal cases, a judgment must be reached. There are easy cases and hard cases.

In easy cases, its very clear what the law is and what the facts are, and the judgement is arrived at through logical deduction.

In hard cases, the law and the facts are more vague. In that event what actually happens is that judge uses his or her moral intuition to sense which side should win, then constructs a story out of the law and the facts to make it so. Now, judges and lawyers probably take strong exception to what I just said, but psychologists who study morality and moral reasoning can make a very strong case that what I said is how it actually works deep down under the hood. Judges don't realize that's what they are doing because they only know what 5% of their brains are doing (conscious awareness), the rest is hidden, and its the hidden part that is making the real decision when the law and the facts are vague. The constructed story has takes appearance of logic, but it constructed after the decision has already been reached. That's how different judges can reach different decisions given the same facts and same laws.

Therefore, what is puffery and what is false advertising depends on easy case or hard case, and on the particular judge.
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You make it sound like people in the judicial system are one step above knuckle dragging dolts.
 
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#90,567
anatech said:
Hi Robert,
I wouldn't say it that way, but in small claims court, that is in fact how things work. That's if you are lucky and they haven't made up their mind beforehand.

-Chris
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Often different opinions are arrived at from the same law and same facts on the Supreme Court, for the hard cases of course. It's not just the lower courts.

Actually though, I should point out that what I described is a somewhat simplified model of reality. Psychologists have more complex models of human behavior for that can offer further insights, but the basic model is a pretty close approximation.
 
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#90,570
Markw4 said:
In legal cases, a judgment must be reached. There are easy cases and hard cases.

In easy cases, its very clear what the law is and what the facts are, and the judgement is arrived at through logical deduction.

In hard cases, the law and the facts are more vague. In that event what actually happens is that judge uses his or her moral intuition to sense which side should win, then constructs a story out of the law and the facts to make it so. Now, judges and lawyers probably take strong exception to what I just said, but psychologists who study morality and moral reasoning can make a very strong case that what I said is how it actually works deep down under the hood. Judges don't realize that's what they are doing because they only know what 5% of their brains are doing (conscious awareness), the rest is hidden, and its the hidden part that is making the real decision when the law and the facts are vague. The constructed story has takes appearance of logic, but it constructed after the decision has already been reached. That's how different judges can reach different decisions given the same facts and same laws.

Therefore, what is puffery and what is false advertising depends on easy case or hard case, and on the particular judge.
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Sadly that is pretty true at all levels of the law.
 
#90,571
Hi Anatech,

As far as I could see, te 3250 preamp circuitry is EXACTLY the same as the preamp section of the 1180.

Re. H/K PA 2400, I beg to differ. This is a still more competent beast than the Marantz 300 DC and is, to the best of my knowledge, the best work ever by H/K not counting the legendary Citation XX. Its prodigious power into evil loads is the least of it, believe me, it has finesse and nuance, of course, assuming your preamp can deliver. And. much like the Marantz DC amps, it also imparts a feeling of limitless power available on tap - an illusion, of course, but one very dear to me, by the time the amp starts to need to breathe deep, I'm already using insane loudness levels way past enjoyment.

I'm way past improvements, I'm a lazy old geezer now concentrating on my CD collection and loads of listening. Just one unfinished project on my worktable, I'll get it done in a month or so (or so I hope), it will probably take a few months to fully develop, and that'll be that. Nothing but music left then.
 
#90,574
Hi dvv,
As far as I could see, te 3250 preamp circuitry is EXACTLY the same as the preamp section of the 1180.
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That's possible. I'm working on a 2285B at the same time, and parts of that might be creeping into my memory. I'll be going over the preamps section of my 1180DC soon enough. It wouldn't surprise me if it was identical.

I've worked on HK PA 2400 before. The 300DC does have better sounding highs than the PA 2400. That's even after I've done my thing on both amps. The high bias current in the drivers doesn't save this amp from it's voltage amp section.

I've bottomed out the woofers by mistake before, they are PSB Stratus Gold speakers, and the amplifier didn't even hint at power problems before the speaker did. But yes, there is no shortage of amplifiers that have much higher output power than my little 300DC. I keep going back to the Marantz in my main listening room. My wife likes the Marantz gear a lot more too. I'll be removing the Cyrus MonoX amplifiers soon to install the Marantz set up again.

-Chris
 
#90,575
Hi FdW,
Yes, I have watched a bit of Judge Judy. She is abnormally bright for a small claims court Judge, and she weighs her options carefully it seems. I have had personal experience with the small claims court, all the way up to the Supreme court here in Canada. The different levels of court describe the judge ecosystem very accurately I would say. They all start low and rise to their level of ... Some are capable of even higher levels of performance. Same as in any profession.

-Chris
 
#90,577
anatech said:
Hi dvv,

That's possible. I'm working on a 2285B at the same time, and parts of that might be creeping into my memory. I'll be going over the preamps section of my 1180DC soon enough. It wouldn't surprise me if it was identical.

I've worked on HK PA 2400 before. The 300DC does have better sounding highs than the PA 2400. That's even after I've done my thing on both amps. The high bias current in the drivers doesn't save this amp from it's voltage amp section.

I've bottomed out the woofers by mistake before, they are PSB Stratus Gold speakers, and the amplifier didn't even hint at power problems before the speaker did. But yes, there is no shortage of amplifiers that have much higher output power than my little 300DC. I keep going back to the Marantz in my main listening room. My wife likes the Marantz gear a lot more too. I'll be removing the Cyrus MonoX amplifiers soon to install the Marantz set up again.

-Chris
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That's hitting the nail on the head, Chris. I will not fool around with Marantz gear because I want to preserve it in its original state so I can reconnect it all as a system any time I feel like it just because I feel like it. Quite simply, it pleases me, including my also auncient Dual CS 604 DD TT - it's a match made in heaven, it gets what you wouldn't believe from my Ortofon M2 Blue cartridge and all in all I have what I think must have been a 70ies rock fan dream system, tightly fitted into a neat 39...18,000 Hz +/- 1.5 dB speaker response, L-R speaker tolerance below 0.5 dB, delivering reasonable 92 dB/2.83V/1 m SPL. It's almost amazing what can be heard from old time LP recordings. It all sounds so good together I am simply not stimulated to fool around with it.

If I should get bitten by the bug again, well, I can always unpack the Philips Black Tulip tuner, preamp and power amp and have a go, they are all well made, but sonically they could (and should) be doing better.

My ONLY change introduced to the Marantz boys was changing their dual concentric 12,000 uF and twin 15,000 uF caps in the 170 and 1180 for B.C. Components (ex-Philips) 22,000 uF milk cans. A hard fit, but I did it in the end.
 
#90,578
Hi dvv,
I normally enjoy working on Marantz, the end result is very worthwhile. Of course I come at it from a place where I used to do warranty service on these. Always loved this equipment.

Now looking at it from a restoration POV, I like the improvements in sound quality I can deliver on this stuff. I've also had to replace those darned capacitors with normal snap-in caps. 8,200 uF instead of 6,800 uF while I was at it, and onto a special PCB that I have yet to design. I just received the capacitors last Friday. The 2285 was "Struck by Technician", so lot's of fixes required. Why is it so darned difficult to install the correct lamps for these??!! I've even found 6 V 300 mA lamps installed, along with the destroyed reflector.

I see each repair as a restoration, not a repair really. But in each case, the customer has been thrilled with the result.

-Chris
 
#90,579
The level of ignorance is stupefying to say the least in the average public let alone on the Bench. I just did a service call on a machine that I've never seen before and it was amazing that the customer for this repair had been on the phone with the manufacturer and nobody asked them to look at the timer on the machine. The machine used hydraulics to move a platten up and down and not much more besides a heating function. Well the machine wouldn't go down, it just sat there and didn't move. Well there was a timer that controlled how long the machine went down and held and then returned to the start position. Well if the timer says zero why would it move, it thought it was finished! Took all of about 5 minutes to diagnose and repair the machine, if you call that a repair. Can people even read a manual anymore, on top of that I had to tell the manager how to fill in a check to pay me. I took the money but felt like I was dealing with people without a clue.
 
#90,580
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