Well......it’s like this. In a flea bay type situation i’d be lucky to get $1200 for it.
It’s more principal at this point......I see a good product that was taken from behind in manufacturing.
If I lose the patient I will not cry, I have a better sounding unit in use so I will not be without sound. And to tell you the truth I’m comfortable that I can make these mods without screwing it up.......I might come off as a moron in my quest for information but I’m really not.
I appreciate everyone’s concern though 🙂
It’s more principal at this point......I see a good product that was taken from behind in manufacturing.
If I lose the patient I will not cry, I have a better sounding unit in use so I will not be without sound. And to tell you the truth I’m comfortable that I can make these mods without screwing it up.......I might come off as a moron in my quest for information but I’m really not.
I appreciate everyone’s concern though 🙂
Bob, I am sure you will get the hang of electronics soldering pretty quick if you practice on some junked boards first.
This kind of job is elementary and essentially zero risk despite Marks concerns.
Do you mind also to remove one of the connector boards and take a pic of both sides please?.
Dan.
This kind of job is elementary and essentially zero risk despite Marks concerns.
Do you mind also to remove one of the connector boards and take a pic of both sides please?.
Dan.
Ok thanks, exactly as I expected.
Did you order/get a soldering iron yet ?.
Dan.
It already had some oxidation forming on the pins.
I thought gold plating in contact with tin plating was not optimum either? (As in pcb to post/nut)
And I also thought that was the whole point.....to eliminate the connector?
I thought gold plating in contact with tin plating was not optimum either? (As in pcb to post/nut)
And I also thought that was the whole point.....to eliminate the connector?
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Yes, and the pcb, best to wire direct to the banana posts like I have shown.
Dan.
They carry full speaker current. You suggest direct soldering to a binding post as well, so why are you asking??
It can be seen from your photo. Oxidation + arc makes nothing appreciable.
X2; and if you're going to solder things directly, find which connections might actually matter and do only that so you lose the least serviceability, e.g. output to binding posts.
Use wire terminal , nut and spring washer for conection to binding posts, instead of soldering..
LH0033 hybrid as output stage of headphone amp
Although I had several LH0033s to play with, I didn't want to risk them in an unproven and not-bug-free amplifier board. So I decided to build an "emulator" daughter card, which plugged into the LH0033 socket and performed the same function, using low cost, easy to buy, active production components. If I destroyed a few of the emulator cards, so what. They're easily replaced.
Then the penny dropped. I realized that these LH0033 emulators were, in fact, interchangeable Output Stage Daughter Cards. I could swap new output stage designs in and out, as often as I liked. Perhaps to optimize measured performance, perhaps to optimize listening pleasure, perhaps to minimize parts cost, or perhaps to use up my stash of 1971 Linear Hybrid devices. Eureka.
Besides the LH0033 itself, here are some of the daughter cards I built to drop into the output stage socket. A couple of them use the "Objective 2 HPA" idea of parallel opamps with 1R5 balancing resistors; in my case, four parallel opamps, i.e. two duals. Then there's a BUF634A, an LME49600, and a discrete push pull buffer using 200 MHz VAS transistors in the TO126 package. And, perhaps, more to come.
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Although I had several LH0033s to play with, I didn't want to risk them in an unproven and not-bug-free amplifier board. So I decided to build an "emulator" daughter card, which plugged into the LH0033 socket and performed the same function, using low cost, easy to buy, active production components. If I destroyed a few of the emulator cards, so what. They're easily replaced.
Then the penny dropped. I realized that these LH0033 emulators were, in fact, interchangeable Output Stage Daughter Cards. I could swap new output stage designs in and out, as often as I liked. Perhaps to optimize measured performance, perhaps to optimize listening pleasure, perhaps to minimize parts cost, or perhaps to use up my stash of 1971 Linear Hybrid devices. Eureka.
Besides the LH0033 itself, here are some of the daughter cards I built to drop into the output stage socket. A couple of them use the "Objective 2 HPA" idea of parallel opamps with 1R5 balancing resistors; in my case, four parallel opamps, i.e. two duals. Then there's a BUF634A, an LME49600, and a discrete push pull buffer using 200 MHz VAS transistors in the TO126 package. And, perhaps, more to come.
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Mark you probably answered this earlier (apologies) but is your LH0033 circuit a composite or sequential stages? I'm assuming the latter or you had a lot of loop gain compensation practice! Cool stuff.
Daniel, it's a composite. However the LH0033 is only a unity gain buffer so it doesn't increase the loop gain. It does add a few degrees of phase shift at the unity gain frequency of the entire loop.
Here are the exhibit plaques that I placed next to the amplifier on display at Burning Amp. I think they probably tell you exactly what you want to know.
MJ
{I did exhibit another composite amplifier called "Rojo", with a total of ~180 dB of loop gain. An IC opamp in series with a high power discrete opamp. Yes it was fun to figure out how to compensate that unholy swamp. No it didn't use LH0033s.}
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Here are the exhibit plaques that I placed next to the amplifier on display at Burning Amp. I think they probably tell you exactly what you want to know.
MJ
{I did exhibit another composite amplifier called "Rojo", with a total of ~180 dB of loop gain. An IC opamp in series with a high power discrete opamp. Yes it was fun to figure out how to compensate that unholy swamp. No it didn't use LH0033s.}
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As they say, curiosity killed the
You've been informed about the "fool's errand" relating to this attempt. It's now up to you to digest the info.
The end result of Marks composite amp seemed pretty good. Old technology becomes art and useful at that.
Ah very cool! Sounds like it was a fun and fulfilling project. Reminds me that I have a bin of rescued TDA7293's that I was going to build an unholy front end for and tap in for their outputs. Logical? No, but fun in its arbitrariness.
Pavel -- one gets the impression that using the LH0033 was more for the challenge and satisfaction of marrying "ancient" parts in a modern way than for the absolute best performance money could buy.
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