Yes, the NJM part simply shares the four digit number --- it's not a cross-licensed LM4562, as for one thing I don't think National/TI would reveal a simplified schematic at this point. And the performance numbers are very different.
Sometimes, when the digits have become very famous, like the examples benb cites, a duplicated/second-sourced part will indeed share the numbers, like the NJM13700, which really is a form-fit-function near-equivalent to the LM13700.
I wonder if someone could actually trademark just the numbers? I'd suppose not, but then I never imagined that Monster Cable could trademark essentially all uses in a trade name (including employment services and restaurants) of the word "monster". I still chuckle that Noel Lee bought the right to rename Candlestick Park as Monster Park, for quite a chunk of change, yet most people presume it was renamed for monster.com.
Brad
It was what it was in its time. Today, it's more or less a dead transistor conducting.
What it lacked was a decent complement, and the 2N2955 came quite a bit later. Yet, the British audio industry, specifically Arcam, used them as power trannies in their products all the way to the late 80ies.
On a different subject, I need some help in understaning.
On several occasions, I have seen devices with series connected, very standard resistors, for example three 5K6 in a row.
I am trying, but constantly failing to understand why. 3x5K6 id 16.8k, and 16.7k is a standard E94 value. Furthermore, the cost-conscious industry is not likely to love using 3 resistors where 1 would do, as it costs more to buy and more real estate in the PC board.
So, I conclude there is a reason which completely eludes me.
Why? What's the reasoning behind this move?
On several occasions, I have seen devices with series connected, very standard resistors, for example three 5K6 in a row.
I am trying, but constantly failing to understand why. 3x5K6 id 16.8k, and 16.7k is a standard E94 value. Furthermore, the cost-conscious industry is not likely to love using 3 resistors where 1 would do, as it costs more to buy and more real estate in the PC board.
So, I conclude there is a reason which completely eludes me.
Why? What's the reasoning behind this move?
Lower cost- remember, it's not just the cost of a single board, it's the overall BOM costs for all product lines that counts; quantity breaks can make (say) 1 million 5k6, of which 30,000 are used in this particular SKU, be a lower cost alternative to 10,000 16k7 that aren't used in other SKUs.
Also a possible reason is to minimize the voltages across each resistor, thus reducing the voltage coefficient and the change in resistance due to it.
Consider also a voltage divider (jcx recently linked to an old thread which seemed to be about this to some extent) in which a plurality of same-value parts for a feedback divider was used. To the extent that each part was similar, and the divider lightly loaded and seeing similar shunt capacitances, changes in value due to voltage coefficient and thermal shifts will tend to compensate for one another.
Consider also a voltage divider (jcx recently linked to an old thread which seemed to be about this to some extent) in which a plurality of same-value parts for a feedback divider was used. To the extent that each part was similar, and the divider lightly loaded and seeing similar shunt capacitances, changes in value due to voltage coefficient and thermal shifts will tend to compensate for one another.
Similar trick was used in thick film ICes where the same line or zig-zag, the same paste, were used to make a voltage divider, just physically divided by a conductor in needed place. Tolerances were allowed 20%, but divide ratio was much better.
Agreed, but what I saw was simple load impedance, i.e. the dumbest possible function, however necessary. And ever so near standard E94 values, off by just 100 Ohms (16.8M as 3x5K6 vs. 16.7K standard value, in HK 870 power amp). My point is, those lost 100 Ohms were surely NOT the reason why it was done as 3x5k6.
It is not always about the component cost. If you want to stay in business you need to look at the total cost of quality which may include customer perceptions and other intangibles as well as the suppliers ability to maintain the chain at the correct time. JIT is really bad news when it's a day late and you shut down production because someone saved $5. The buyer needs to get the best value to the business. Much harder than the lowest price.
Now, go to the local store and look at the cheapest calculator. Consider all the parts, all the processes of assembling it, packaging, and shipping. If I did not see them, I would tell you it was impossible.
Today I decided to replace 40 years old time relay for frontyard watering, it was worn-out mechanically. New device has output for 4 stations, cool intuitive microprocessor control, LCD display. I connected it, programmed, and tried to run. After 4 minutes it started shutting valves off and on, with about 1 second period. On lcd "No AC" started flashing in tact with valves. I decided to open it and see what is wrong...
Looks like they tested it on a bench in laboratory conditions only, and never expected temperature to be 80 degrees F. And started manufacturing and selling such production... However, it is not about sound quality directly, but who today dares to build prototypes and test them in the field? It is costly, production run from computer files is much cheaper.
Now I have a new timer for $19 only, but it turned to be a DIY project. How long will it last? I do not know, but the previuous one had vbeen ticking long time before I bought the house...
Looks like they tested it on a bench in laboratory conditions only, and never expected temperature to be 80 degrees F. And started manufacturing and selling such production... However, it is not about sound quality directly, but who today dares to build prototypes and test them in the field? It is costly, production run from computer files is much cheaper.
Now I have a new timer for $19 only, but it turned to be a DIY project. How long will it last? I do not know, but the previuous one had vbeen ticking long time before I bought the house...
Last edited:
It appears my Polish cousin and I move along similar trajectories, at least in principle. I also have a new project, albeit not a big one.
A couple of days ago, I purchased this:
a Luxman C-03 preamplifier. At €250 (app. $320) I just couldn't resist it, all the more so since I know the seller very well. Pristine condition doesn't really describe it. It was manufactured 1987-1994, an uncommonly long market life for any model in audio, and it sold very well indeed.
Look at the boards, if you happen to see any dust, do let me know:
So, ultimately, refreshing it really means changing about 40 electrolytic capacitors.
It's chock full of dual FETs, dual transistors and the works, meaning it's really well made, without going wild.
I bought it for three reasons: 1) I know the seller, and he is a very careful man, and consequently, the item is in outstanding condion, just one small scratch above the tone controls; 2) I never onwed anything by Luxman, so I guess I'm curious enogh to take a dive, and 3) At that price, it's simply not worth my while to make a preamp for my upcoming power amp, and I don't want to break up the Marantz 3250B/170DC preamp/amp combo.
I just looked at it over the last 3 days, sort of savoring it, and today, I get to connect it, using the Marantz 170 DC power amp as the companion. Fortunately, all my integrated amps (except the Karan) can also be used as pre or power amps, so I can try it out with the Harman Kardons and the Sansui as well.
A couple of days ago, I purchased this:
An externally hosted image should be here but it was not working when we last tested it.
a Luxman C-03 preamplifier. At €250 (app. $320) I just couldn't resist it, all the more so since I know the seller very well. Pristine condition doesn't really describe it. It was manufactured 1987-1994, an uncommonly long market life for any model in audio, and it sold very well indeed.
Look at the boards, if you happen to see any dust, do let me know:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
So, ultimately, refreshing it really means changing about 40 electrolytic capacitors.
It's chock full of dual FETs, dual transistors and the works, meaning it's really well made, without going wild.
I bought it for three reasons: 1) I know the seller, and he is a very careful man, and consequently, the item is in outstanding condion, just one small scratch above the tone controls; 2) I never onwed anything by Luxman, so I guess I'm curious enogh to take a dive, and 3) At that price, it's simply not worth my while to make a preamp for my upcoming power amp, and I don't want to break up the Marantz 3250B/170DC preamp/amp combo.
I just looked at it over the last 3 days, sort of savoring it, and today, I get to connect it, using the Marantz 170 DC power amp as the companion. Fortunately, all my integrated amps (except the Karan) can also be used as pre or power amps, so I can try it out with the Harman Kardons and the Sansui as well.
Hi,
Shame.
Nice as it is, the cheaper C-02 is reckoned by most that know this stuff much better.
Still, used as line-stage only and without Tone Controls it should be pretty good. Can drive headphones directly of the Linestage.
Ciao T
It appears my Polish cousin and I move along similar trajectories, at least in principle. I also have a new project, albeit not a big one.
A couple of days ago, I purchased this:
a Luxman C-03 preamplifier.
Shame.
Nice as it is, the cheaper C-02 is reckoned by most that know this stuff much better.
Still, used as line-stage only and without Tone Controls it should be pretty good. Can drive headphones directly of the Linestage.
Ciao T
Oddly enough, I was told the exact opposite. I did ask, because I am completely unacquainted with Luxman in general, so I thought it prudent to ask Luxman afficitionados.
I haven't switched my TT on for the last 16 years, so it won't see much service there, it'll be all line stage.
As for driving headphones, yes, it does that directly from the line stage, which explains some of those heat sinks on the picture. However, I still do have all three models of my own headphones amps, and both my sources (tuner and CD player/DAC) have dual outputs, so I can always use direct connections for the headphones.
Any news of your power amp, Thorsten?
Mine is ready to go the printed circuit board design stage. In the end, I did take your advice and go for the FETs in the input stage differential amps. The only other signficiant change is that I now use not two, but three paralleled trannies in the second stage.
And I'm still a small timer, Dan d'Agostino uses 118 of them altogether in the voltage gain stages.
I played a lot with the design, trying out different transistors and circuits, and I discovered that using 3 MPSA92/42 trannies reduces high frequency distortion to an extent, nothing spectacular, but it's there. And, being the Motorola/ON Semi affictionado, I just happen (by sheer chance, of course) to have about a suitcase full of them, so matching them is reduced to coffee sipping, cigar puffing, music listening nicely spent time of manual labor.
- Status
- Not open for further replies.