If you look at 1014 the RCA and Sincalir amps show early version of the chosen design in the book . I took interest in this as people who disliked Naim Audio often said the Naim is simply the RCA . It isn't . It strongly resembles the Sinclair with some interesting tweaks .
Looking at the RCA the compensation it is not what would become the generic Cdom . I have seen a few amps that extend Cdom to for example the output stage . Anyone have interesting versions ? Anyone want to analyze the RCA ? The Gogny was interesting . From what I know the previous amp was perhaps valve with output transformer . Quite a step to do what he did . As far as I know he had no previous reference point ? If anyone looks and wonders the LTP is configured as valve pre amp input ( inverting ) and others . There is also feedback from the panel speaker . The texts says the 3055 has a gain of 5 used as it is here , thus a 3055 drives a 3055 . I will one day build it as it might drive motors well and have loads of 3055's . I will fit bootstrap CCS to see what happens . Strange he didn't .
My friend John has a Sinclair module . We plan to give it some Motorola outputs to see how good the design is . Best amp in the world circa 1970 as Sinclair claimed ? Perhaps that is not to far from the truth . As with the Gogny we will tweak the bias as there is no point in have it bad for historical reasons .
Looking at the RCA the compensation it is not what would become the generic Cdom . I have seen a few amps that extend Cdom to for example the output stage . Anyone have interesting versions ? Anyone want to analyze the RCA ? The Gogny was interesting . From what I know the previous amp was perhaps valve with output transformer . Quite a step to do what he did . As far as I know he had no previous reference point ? If anyone looks and wonders the LTP is configured as valve pre amp input ( inverting ) and others . There is also feedback from the panel speaker . The texts says the 3055 has a gain of 5 used as it is here , thus a 3055 drives a 3055 . I will one day build it as it might drive motors well and have loads of 3055's . I will fit bootstrap CCS to see what happens . Strange he didn't .
My friend John has a Sinclair module . We plan to give it some Motorola outputs to see how good the design is . Best amp in the world circa 1970 as Sinclair claimed ? Perhaps that is not to far from the truth . As with the Gogny we will tweak the bias as there is no point in have it bad for historical reasons .
JBL SA600, in 1966 : differential input, inverting, amplifier.
Four transistors only for the input + main voltage gain stages.
Triple push-pull followers for the output stage.
I wonder when Radford ZD50 amp appears.
Differential input; bootstrapped non-inverting input (like in some Self's circuits);
cascode voltage stage: a kind of diamond circuit for the push-pûll output stage,
NNP follower loaded by a CCS and then a Sziklai pair with PNP input
for the positive branch.
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By "close" the differences are all that matter to me. This is where I started and eliminating all the second order errors was the goal. This circuit does not attend to any of them.
The LM118 is the NE5534's antecedent, so establishing who designed the former will give a pretty good idea who designed the latter.
http://www.ti.com/lit/an/snoa850/snoa850.pdf
http://www.ti.com/lit/an/snoa850/snoa850.pdf
Sure that with a discrete design they hardly had the comfort
of using 20 or 30 transistors wich is easy in an integrated design
that can also benefit from tailored transistors caracteristics ,
i dont think that the 797 had to deal with the NE5534 slow
lateral PNPs.
Data sheet says it's in an "advanced complementary bipolar (CB) process". But even so, I'm pretty sure Scott purposefully violated the base design rules, to make the low noise spec. 0.9nV/rtHz in any high voltage old-ish process is by default not possible, it doesn't fit the 40V base layer sheet resistance.
Whatever , it s doubtless than 5534 was a far greater
achievment in its time that the 797 wich benefited from
an hugely better and tailored process ; i would be curious
about what could have been done with this topology if ever
it used the same process as the 5534.
From the tech doc you quoted :
Nonsense, by the same logic, tubes were far greater achievement in their time than the 5534, which took advantage of hugely advanced physics and manufacturing processes.
There were no downplaying intended Scott , indeed , i can only
aknowledge that your 797 is one of the most interesting
op amp of our current times , i just wanted to highlight
that enginering skills cant compensate devices intrinsical
caracteristics , you ll surely agree that such circuits
wouldnt had worked so well with an inferior process.
You should use another straw...
We re talking of SS devices , namely BJTs vs BJTs.
NE5534
Thanks for these gems, Edmond.
TDA1034 was almost certainly developed in the Mullard Applications Lab.
Circa 1976, we (Wharfedale) approached them for suggestions for Low Noise applications. They provided samples of a then secret OPA which we used in gear for our Blind Listening Tests for many years. Later, this & BFW11 were the basis of Calrec's in house measurement system.
The draft datasheet was TDA1034 with the name blanked out but showed the internal circuit which is now enshrined in many publications including Self's book(s).
Dunno about Rupert Neve but Calrec certainly used NE5532/4s in large production mixers (L series? and the early Soundfield mikes) before the (time) equivalent Neve desks.
Signetics was the brand under which most Philips 5532/4 were sold but in dem days, they were made in the Mullard Southampton plant.
Signetics had moved production to Thailand (?) by 1990.
Mullard Applications Lab, where the famous valve designs were developed, became Philips Research Labs some time in the 80's.
The proverbial Dutchman's uncle!
Thanks for these gems, Edmond.TDA1034 was almost certainly developed in the Mullard Applications Lab.
Circa 1976, we (Wharfedale) approached them for suggestions for Low Noise applications. They provided samples of a then secret OPA which we used in gear for our Blind Listening Tests for many years. Later, this & BFW11 were the basis of Calrec's in house measurement system.
The draft datasheet was TDA1034 with the name blanked out but showed the internal circuit which is now enshrined in many publications including Self's book(s).
Dunno about Rupert Neve but Calrec certainly used NE5532/4s in large production mixers (L series? and the early Soundfield mikes) before the (time) equivalent Neve desks.
Signetics was the brand under which most Philips 5532/4 were sold but in dem days, they were made in the Mullard Southampton plant.
Signetics had moved production to Thailand (?) by 1990.
Mullard Applications Lab, where the famous valve designs were developed, became Philips Research Labs some time in the 80's.
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