If you still love Etymotic ER4, this is the thread for you...
Nov 5, 2020 at 5:46 AM Post #15,709 of 17,903

Esers

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I've never heard this. Are you sure?
Yes, I'm sure about that.
All er4p er4s er4b have same driver, same earpiece. Only difference are the impedance network in the cable. er4p being around 18ohm resistor, er4s around 92ohm resistor and er4b has a parallel high pass path 0.22uF + 100ohm.

New generation er4sr er4xr er3se er3xr all have resistors built in the housing behind the driver. Cable are no longer different.
Those drivers are the same. It has been comfirmed many times in the forum, by both forum members who own all of them as well as EtyDave himself (who helps to design them all those years ago).



4P with P-to-S adapter actually does not always add up to the exact same impedance as one piece 4S. It doesn't actually matter that much because once you pass certain impedance, they all measured (and sound) fairly close to identical as long as the difference isn't a big number. That means 100ohm ER4 will be almost the same as, said 120ohm ER4 under measurement. So a few ohm of difference here and there isn't going to be a big problem.
 
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Nov 5, 2020 at 8:32 PM Post #15,714 of 17,903

ClieOS

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Does anyone know where I might find an adapter/converter to convert an ER-4P into an ER-4B?

To add to what others has mentioned, quite awhile ago I believe a guy (?) actually built a custom crossover circuit that will turn an ER4P in ER4B without changing cable, but it was rather expensive. Building the whole cable is probably easier and cheaper, as long as you know how to solder. If you want to buy from someone on the web, do make sure to ask very clearly whether it has the right ER4B circuit or not as most of them are selling an naked cable with ER4 plug and just claimed to be 'ER4P/S/B' compatible, but won't give you the correct sound.
 
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Nov 5, 2020 at 9:19 PM Post #15,715 of 17,903

Rpell

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To add to what others has mentioned, quite awhile ago I believe a guy (?) actually built a custom crossover circuit that will turn an ER4P in ER4B without changing cable, but it was rather expensive. Building the whole cable is probably easier and cheaper, as long as you know how to solder. If you want to buy from someone on the web, do make sure to ask very clearly whether it has the right ER4B circuit or not as most of them are selling an naked cable with ER4 plug and just claimed to be 'ER4P/S/B' compatible, but won't give you the correct sound.

Yes, my understanding is that the ER-4P cable has a built-in 27-ohm resistor while the P-to-S adapter adds another 75 ohms in series to make it equivalent to the 100 ohms resistance in the 4S cable. Based on the Etymotic patent, it appears the original 4B filter network is a 100 ohm series resistor (like the 4S) except that it is also paralleled with a series 100 ohm/0.22 uF RC circuit.

So to convert the 4P (or 4S for that matter) to a 4B I think it's necessary to replace the original ER-4P cable with either a custom cable that includes the 4B filter circuit or use an available generic ER4S/P/B replacement cable (with no built in resistor) and then add a separate adapter/converter containing the 4B series/parallel RC circuit (comprising two resistors and one capacitor per channel). I think the latter is probably the easiest and most versatile solution.
 
Nov 6, 2020 at 1:08 AM Post #15,716 of 17,903

ClieOS

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...
So to convert the 4P (or 4S for that matter) to a 4B I think it's necessary to replace the original ER-4P cable with either a custom cable that includes the 4B filter circuit or use an available generic ER4S/P/B replacement cable (with no built in resistor) and then add a separate adapter/converter containing the 4B series/parallel RC circuit (comprising two resistors and one capacitor per channel). I think the latter is probably the easiest and most versatile solution.

I has built a few ER4B cable where I put the circuit in different location: (1) inside the 3.5mm plug (which you will need a larger 3.5mm plug for accommodation), (2) inside the Y-splitter and (3) inside the 2-pins adapters. Personally my preference is the Y-splitter as it has the cleanest look of all, though also the most difficult to built.

Here is one inside the Y-splitter that I built awhile back for @Degru :
10360865.jpg


Here is one inside the 2-pins adapter so it can also accommodate a mic+remote
11296476.jpg
 
Nov 6, 2020 at 2:07 PM Post #15,719 of 17,903

intellione

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I has built a few ER4B cable where I put the circuit in different location: (1) inside the 3.5mm plug (which you will need a larger 3.5mm plug for accommodation), (2) inside the Y-splitter and (3) inside the 2-pins adapters. Personally my preference is the Y-splitter as it has the cleanest look of all, though also the most difficult to built.

Here is one inside the Y-splitter that I built awhile back for @Degru :
10360865.jpg


Here is one inside the 2-pins adapter so it can also accommodate a mic+remote
11296476.jpg
Do you sell this cables? I have er4p with a dead cable that I plan to replace. I am looking for a cable with volume regulator and mic if possible.
 
Nov 6, 2020 at 2:12 PM Post #15,720 of 17,903

Rpell

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Ok, here is a universal schematics of P-S-B I found
1604660237002.png

and P2B from old Korean forum:
1604660205001.png

Not sure how valid these are

Thanks for finding these schematics. The top image of a P-S-B switchable adapter looks like it was designed to be used with an existing 4P cable, however the 'B' circuit shown uses only a capacitor (680 nF) rather than a series resistor and capacitor in parallel with the 73 ohm resistor. That does accomplish the high-pass filtering, but would mean the impedance of the total headphone circuit at high frequencies (~20 ohms) would be lower than that of the original 4B circuit (~50 ohms).

In the second image, the top circuit is consistent with the original 4B circuit shown in the Etymotic patent. The bottom circuit in that image looks like it also may be showing a custom 4P-to-4B circuit, with the 18 ohms representing the resistance in the existing 4P cable (?). In this case the total headphone circuit impedance at high frequencies is right in line with that of the original 4B circuit (i.e., ~50 ohms), so that looks promising.
 

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