hello,
i would like to know the formula for attenuations of tapped autotransformer, if someone can help me, thanks.
hello,
i would like to know the formula for attenuations of tapped autotransformer, if someone can help me, thanks.
Phil
Question: 09-24-2003, 05:46 PM
Answer: 02-10-2005, 05:37 AM
Is that service or what!?
Ok. I put this graphic together after lifting the tapped autotransformer pic from here - http://www.allaboutcircuits.com/vol_2/chpt_9/5.html
This is something I've been meaning to put together for a very long time.
I am indebted to David Smith for supplying the fundamental formulas for my spreadsheet.
Modeling a tapped autotransformer courtesy of David Smith.
Another model using my software showing the spice data
David's LEAP Crossover Shop software is better in that it automagically calculates the secondary inductance value.
Hey,
good stuff Thanks.
Is there some formula to convert it to this series and parallel R/L substituting circuit?
You somewhere posted this for the 3145 network but it would be useful to be able to convert all the other networks with these tapped AT's
Not that I know of. Those conversions were all done the hard way. Greg Timbers supplied the original voltage drives along with a few suggestions and I had to plug and chug until the voltage drives looked identical. I never did get around to doing the 4315, L65, S21, or L220. I think Tim G might be able to import voltage drives into SoundEasy and do something with them.Originally Posted by Guido
Originally Posted by Giskard
hello,
i just see (saw?) your post, you don't forget me !
i'm very happy ...
very good post, thanks. fonzy
Phil
Hi Fonzy,
I send you a P.M about this case
Regards
OK, so building 4315, L65, S21, or L220 will be a challengeOriginally Posted by Giskard
At least we have the 3145 circuit.
Somebody should give us a little tutorial here. What's this about? How does it apply?
55030 Tapped Autotransformer
In this particular instance, used to make the 52978 "1.55mH" tapped autotransformer in the LX80/LX80A/LX300/N333/3131/3133
Tapped autotransformer shown above measured:
red to black - 1.51 mH 0.69 ohms DCR
1st yellow to black - 0.39 mH 0.48 ohms DCR (-6 dB)
2nd yellow to black - 0.27 mH 0.42 ohms DCR (-7.5 dB, spec'd as - 8 dB)
orange to black - 0.14 mH 0.39 ohms DCR (-10 dB)
red to 1st yellow - 0.36 mH 0.46 ohms DCR (-6 dB)
red to 2nd yellow - 0.52 mH 0.48 ohms DCR (-4.5 dB)
red to orange - 0.75 mH 0.52 ohms DCR (-3 dB)
Using the fomulas posted in #2 above for a 1.51 mH inductor:
It's a way to model tapped autotransformers to simulate voltage drives. Once the voltage drive has been simulated one can replace the tapped autotransformer with resistor pads and regular inductors which will yield the same voltage drive. It's probably easier to do with something like SoundEasy or LEAP Crossover Shop than with something like pSpice.Originally Posted by Zilch
Hi all,
After a PM exchange with Giskard, i would like to inform you about the availability of autotransformers :
2 months ago , i had a talk with a FRench Hartsfield owner ( a Classic Audio Repro) about autotransformers versus L Pad.(IMO L.Pad are ALL poor quality and very imprecise component).
He gave me the information that this kind of transformer was available at SOWTER UK, as a particular order.
http://www.sowter.co.uk/
Then, we decided to order 10 of them in January.THey are on the way from UK to France for the present.
The conditions of the contract included 9 positions, from -1 to -10 db.Contrary to the JBL original parts, those transformers DO NOT includes the L circuit. THerefore you have to instal the inductor separatly, thus the 10 stepped selector with the different resitors in front of the circuit.( scheme included)
The price of each transformer is about 140 €/180 $ without local taxes.
I hope it could help!
Warmest regards,
Measured impedance curve of 1.55 mH tapped autotransformer without and with preceding 7.5 ohm parallel resistor.
This is the load the 16.5 uF capacitor sees.
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