There is another not connected pad coming from R8 (above the 10-pin connector), but I guess that goes at the pad on the track connecting C18 and R15 (ground)? Is it really necessary since C18, R15 and all the other parts on that side, that need to be grounded are already grounded?
I put those 2 pads there to optionally close the GND track in order to minimize the resistance, since it is kind of a long track.
But I have a question: What is the purpose of the track leaving from the right end of R16 (just above Q8, at the left part of the pcb) leading to a pad that is not connected anywhere?
That's just a pad I forgot to remove, so you can leave it out.
Later today I can post a slightly updated version of the my layout if you want.
The ESPE01 circuit is very different from dewster's yaewsbm. You used the latter which gives a different result and has never been tested, played and/or approved by one of the professional thereminists. I had already one Etherwave with a self made (by the client) yaewbsm and defective pitch oscillators on my workbench. The deeply deceived owner asked me to take the yaewsbm out, fix the oscillators and install the ESPE01. Be careful!
The ESPE01 circuit is very different from dewster's yaewsbm.
On pictures I saw that the ESPE01 modules and the yaewsbm circuit have the same components in it, so I assumed they where identical. Is the ESPE01 circuit available somewhere?
I am not an electronics expert, but how can 2 simple buffer stages damage the oscillators?
In fairness, the question that needs to be asked is this.. Was the self made YAEWSBM correctly built? Was it faulty?
You see, I strongly suspect Thierry, that if you had published your ESPE01 circuit, and this was being added to EW's by DIY incompetents, there would be failures - not due to the design, but due to wrong construction.
As for "never been tested, played and/or approved by one of the professional thereminists" I would argue that the performance by Bisem (presented here on TW) demonstrates a competence in playing at least equal to what I have heard you do, and demonstrates the YAEWSBM as a functional design -
I am also sure that MANY people who cannot afford to pay the price you ask for your ESP01 board (particularly someone building an EW clone, for whom the cost of the ESP01 alone probably clocks in at the same as the entire component cost for the whole theremin board) , have built the YAEWSBM board, the fact that one has appeared in your lab indicates as much (not statistically significant, but a possible indicator none the less) - And YOURS is the FIRST account I have heard of any problem with it - And you do not actually specify the problem (was there REALLY a problem with the YAEWSBM??)
You have always hated the YAEWSBM, and are NOT placed to make the unwarranted comments you have - there is a CONFLICT OF INTEREST issue here!!! - As the technical "authority" on the TW staff I do not believe you have the right to make statements like this unless you can back them up with supportive TECHNICAL data and reasons, nor do you have the right to make any inferrences which promote YOUR interests at the expense of a TW members standing - Disgracefully however, IMO you do this frequently!
Its only a damn buffer, for gods sake! two 5p transistors, a few R's and C's, and a tiny PCB.. Hardly any "high" technology there to warrant requiring "certification" by "professional thereminists"
I also do not understand why, despite having been corrected on this numerous times, you repeat the word "decieved" rather than use a more appropriate word such as "dissapointed" ..
"The deeply deceived owner asked me to take the yaewsbm out, fix the oscillators and install the ESPE01. " Come across as OFFENSIVE to an english speaker - it implies Deception! - as in DISHONESTY.. You have done this frequently, then fallen back on the tired excuse of not being a native English speaker. STOP DOING IT!
Fred.
I personally like the sound of this EW FAR more than the sound I have heard from any other EW - This is fitted with a YAEWSBM built by Dewster.
"I am not an elektronics expert, but how can 2 simple buffer stages demage the oscillators?" - Wannes_dn
They cant, its as simple as that! - unless wrongly constructed.. there is a 15pF capacitor between the oscillator and the buffer - it would require some MAJOR co*k up to damage the oscillator - even shorting the 15pF capacitor to ground or either supply rail isnt going to blow the oscillator up.. Something else (probably ESD) will have damaged the oscillator, and possibly also the buffer..
I am REALLY angry about this DISHONESTY from Thierry - And its not even my design!
Fred.
PS - I have just run extensive simulations on the EW circuit with the YAEWSBM buffers, I have done every absurd worst-case change of component values etc, I have shorted the input of the buffer to the supplies and ground...
NOTHING I can do to the YAEWSBM alters the loading on the oscillators by more than 15pF or has ANY possibility of damaging them.
The 15pF represents less than 0.5% of the 3300pF capacitive loading on the oscillator, and this 3300pF has component tollerance of 5% at least, so 15pF is utterly and completely insignificant (5% = 165pF, so the capacitance can vary between 3465pF and 3135pF .. 15pF is IRRELEVANT at that point in the circuit)
As an aside (completely unrelated to the YAEWSBM) and with reference to Dewsters posting below:
It is true that the transistors used for the EW are a pathetic choice, much more robust and better transistors are available (I use the Zetex ZTX transistors - they are about 25p as opposed to 5p) - but hey, they would add about a dollar to the cost of the theremin if they were all replaced - which, if one looks at component price vs retail price, would probably mean the retail price of the EW would go up by about $10.. Add another 50c for discharge tubes and the price would go up by $20.. People might start thinking the EW was expensive.....
Thierry, you've seen the YAEWSBM schematic. Is there anything in there you can think of that might cause the oscillator transistors to burn out? I think you mentioned a while back that the EWS transistors were too wimpy in the first place, and that mistuning (with or without the mod?) could burn them out. I've said before that I've seen fairly high currents associated with the stock EWS oscillator topology in my simulations right around tank | EQ resonance.
Could your provide a bit more info on this failure?
@dewster: I'll look up in my notes tonight, this action was already last summer and I don't exactly remember the details. In ever case it was a very strange story.
@FredM: I'll not comment your slanderous remarks for the moment. You seem to have an adrenaline peak and not discuss on a rational base. I'll let go a little time and then I'll write my reply in a calm and reflected mood.
The ESPE01 circuit is not public. The ESPE01 module does not only buffering but also pre-mixer wave shaping by voluntarily having selected parts of the signal amplitude in the non-linear area of the buffer stage which in combination with the arctan(x) input function of the LM13700 gives the nicer timbres. It took me many months to optimize it and I spent a lot of time and money travelling around in Europe to have prototypes played and tested by renowned thereminists like Lydia Kavina, Carolina Eyck, Thorwald Jorgensen, Wilco Botermans and many less known players until everybody was amazed with the result. Out of that I did tests in all variants of Etherwaves (Standard and Plus, and the different circuit board variants released by Moog over the years) to make sure that the result would be the same everywhere and to make sure that it didn't affect the stability of the oscillators. This module has been developed for and together with musicians, and much time, money and "heart blood" has been invested in its development which makes it IMHO not comparable to the "two simple buffer stages" cited above, at least not for the professional musician for whom it was designed.
And yes, my reaction was "allergic" when dewster published his yaewsbm since the latter was presented as being an equivalent for the ESPE01 module for free because this had put me in the light of someone who would take a lot of money for "two simple buffer stages". I think I explained above why I think that this comparison is highly unfair. Let's take an example of the daily life: Imagine the Gilette Company bringing a new 5 blade razor to market. Before this razor would be in the market, they would make long clinical tests with many testers having different skin and facial hair properties. They'd optimize the distance, the angle, and the fixing of the blades to optimize elasticity, invest in an ergonomic design and an optimal weight balance for the handle and so on. All these efforts would naturally have their impact on the sales price. On the other side, you can buy a pack of 10 single or double blade razors with a simple plastic handle and an amovible head for less than 1€50. The latter will allow you to shave, too, but nobody would say that it is the same.
On the other side: If dewster had documented the same efforts and investments in the development of his module and if renowned professional musicians would have stated that his module was better than mine under technical AND musical aspects, I would have been the first to stand back, to throw my ESPE01 in the trash can, and to support the propagation of his version.
FredM wrote: "Come across as OFFENSIVE to an english speaker - it implies Deception! - as in DISHONESTY.. You have done this frequently, then fallen back on the tired excuse of not being a native English speaker. STOP DOING IT!"
I never look up every single word which I write. The English verb "to deceive" has the same roots as the French "décevoir". "Être déçu", literally translated "being deceived", means for me logically that you just did not get what you expected. There is neither dishonesty nor wronging implied.
