D27TG35-06 - Tymphany
D27TG05-06 - Tymphany
A quick search, the "SG" in a Vifa tweeter is either out of production or may have been for OEM only, I'll keep digging. Look at the impedance curves of these two D27 tweeters above, at least they are probably close to the D27SG in question. They are both specified as being 6 Ohms nominal. The Zobel would be used to flatten the impedance curve so the impedance would be some constant value (I chose 6.6 Ohms so the math would work with the attentuator L-Pad calculator that gave the resistor values shown on the schematic; 2 Ohms and 16 Ohms)
D27TG05-06 - Tymphany
A quick search, the "SG" in a Vifa tweeter is either out of production or may have been for OEM only, I'll keep digging. Look at the impedance curves of these two D27 tweeters above, at least they are probably close to the D27SG in question. They are both specified as being 6 Ohms nominal. The Zobel would be used to flatten the impedance curve so the impedance would be some constant value (I chose 6.6 Ohms so the math would work with the attentuator L-Pad calculator that gave the resistor values shown on the schematic; 2 Ohms and 16 Ohms)
The voltage divider calculator is set up for 'impedance bridging' where the load impedance is much greater than the source impedance.
I appears unsuited to loudspeaker L-pad calculations where 'impedance matching' is the goal.
I would caution the layman against using the voltage divider calculator. Rather, use the dedicated L-pad calculator linked to earlier:
HiFi Loudspeaker Design
Yes, agree that the L-Pad calculator should be the first choice. I included the voltage divider calculator link because it can help someone experiment with many values. Those that are unsure should stick with the L-Pad calculator. The voltage divider calculator can also be used obviously but one needs to set the Z load = to the driver impedance. If you look at the driver impedance curves though, you can see how the Zobel is a very useful circuit. Using the voltage divider calculator and plugging in different values for Z load based on the curves vs the standard/nominal driver impedance can help some get a better appreciation of the effects of the many variables that must be taken into consideration; that was my reasoning for including it as an option anyway...
Oldspkrguy, thanks and also the others. You are great.
I have one ocd question right now. There are cement 3 resistors in parallel front of tweeter:
6r measure 6.5
6r measure 6.4
16r measure 17
should be parallel 2.7 but measure 3.1
and
6r measure 6.5
6r measure 6.6
16r measure 16.5
should be parallel 2.7 but measure 3.1?
What must i order for a single resistor: 2.7 or 3 ohm? This is realy confusing to me.
I have one ocd question right now. There are cement 3 resistors in parallel front of tweeter:
6r measure 6.5
6r measure 6.4
16r measure 17
should be parallel 2.7 but measure 3.1
and
6r measure 6.5
6r measure 6.6
16r measure 16.5
should be parallel 2.7 but measure 3.1?
What must i order for a single resistor: 2.7 or 3 ohm? This is realy confusing to me.
The SG version is the one with shielded magnet. Performing quite like the TG likely. The "G" is important (same magnet). "15" is the OEM model code, but I don't think Vifa changed anything, so an off the shelf "00" or "05" should do. Unless it has a chamber behind the pole piece, then pick the "35". And you'd have to check for ferrofluid.
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