I still think re-spacing the inductors would be worthwhile even if not replacing. How were you thinking of making 72uF from the values HiFi Collective have available?
I still think re-spacing the inductors would be worthwhile even if not replacing. How were you thinking of making 72uF from the values HiFi Collective have available?
Darren.
Listening Room.UNDER CONSTRUCTIONTurn Table. Garrard 401 2 Tier Slate Plinth, DIY Hadcock GH242, Nick G modded Lentek, Denon DL-103.
Pre Amp. Croft Micro. Power Amps Quad 405 Mono Blocks.
Speakers. TBC
Home Cinema.UNDER CONSTRUCTIONDAC/Pre Amp. Denon AVC X3700H.BDP/Streamer. Oppo 203 / Apple TV4K.Display. Optoma UHD51 / DIY False Black Window Screen.
Power Amps. 2 x Nakamichi AVP1.
Front Speakers. DIY Baby Celestion Ditton 66. Surround Speakers. Celestion Ditton 11. Subwoofer. BK Electronics P12 300SB PR.
Old Gallery. http://theartofsound.net/forum/showt...-of-the-70%92s
to be honest i hadnt gone that far yet,so dont know if i can get the 72 value using mundorf.
My System
John Wood KT88 Amp.
Paradise Phono Stage
Sony TTS-8000 Turntable.
PMAT-1010 MK6 Tonearm.
Ortofon Cadenza Bronze
Sony X555ES Cd Player
Yamaha NS1000m Speakers
seems using them the closest you can get to 72uf is 71.9 made from a 68uf and a 3.9 i doubt the difference would be audible .
My System
John Wood KT88 Amp.
Paradise Phono Stage
Sony TTS-8000 Turntable.
PMAT-1010 MK6 Tonearm.
Ortofon Cadenza Bronze
Sony X555ES Cd Player
Yamaha NS1000m Speakers
Darren.
Listening Room.UNDER CONSTRUCTIONTurn Table. Garrard 401 2 Tier Slate Plinth, DIY Hadcock GH242, Nick G modded Lentek, Denon DL-103.
Pre Amp. Croft Micro. Power Amps Quad 405 Mono Blocks.
Speakers. TBC
Home Cinema.UNDER CONSTRUCTIONDAC/Pre Amp. Denon AVC X3700H.BDP/Streamer. Oppo 203 / Apple TV4K.Display. Optoma UHD51 / DIY False Black Window Screen.
Power Amps. 2 x Nakamichi AVP1.
Front Speakers. DIY Baby Celestion Ditton 66. Surround Speakers. Celestion Ditton 11. Subwoofer. BK Electronics P12 300SB PR.
Old Gallery. http://theartofsound.net/forum/showt...-of-the-70%92s
The 0.1 difference in value is moot as the tolerance of the larger cap (3%) will give a difference in value of up to 2uF.
I love Hendrix for so many reasons. He was so much more than just a blues guitarist - he played damn well any kind of guitar he wanted. In fact I'm not sure if he even played the guitar - he played music. - Stevie Ray Vaughan
Agreed, however by the same rational a modern single low tolerance 68uF capacitor could be closer to the specified value than the original 72uF Elcap used by Celestion. We have no idea how thorough the manufacturing process was, but judging by the variety of capacitors found in different generation Celestions I'd speculate it wasn't that rigorous and the components were far from hand picked for each pair of speakers. I'm not saying this just to be a dick, but because I'm trying to make improvements to the original construction and (to my ears anyway) have achieved this by improving component quality (e.g. internal wiring) and by following rules Celestion did not adhere to (e.g. inductor placement).
My concern is not about achieving an absolute 72.00uF but how to do it if not using a single value capacitor. The rules suggest if an absolute value cannot be used the next best option is to use equal values in parallel and I don't know what the rule is if this too is not achievable. Looking at Ken's arrangement for the Mid it would seem he is not concerned about these rules and with all the experimentation he has done with the 66 x-over maybe I'm worrying about nothing, but I do like rules!
Using a 68uF with a smaller value capacitor has it's appeal. As you said, the 68uF will undoubtedly not be 68uF so with a handful of low value and low cost capacitors 72(.something)uF could be achieved. I still like rules, with limited (and I'm flattering myself here) technical knowledge, it takes the guess work out .
Darren.
Listening Room.UNDER CONSTRUCTIONTurn Table. Garrard 401 2 Tier Slate Plinth, DIY Hadcock GH242, Nick G modded Lentek, Denon DL-103.
Pre Amp. Croft Micro. Power Amps Quad 405 Mono Blocks.
Speakers. TBC
Home Cinema.UNDER CONSTRUCTIONDAC/Pre Amp. Denon AVC X3700H.BDP/Streamer. Oppo 203 / Apple TV4K.Display. Optoma UHD51 / DIY False Black Window Screen.
Power Amps. 2 x Nakamichi AVP1.
Front Speakers. DIY Baby Celestion Ditton 66. Surround Speakers. Celestion Ditton 11. Subwoofer. BK Electronics P12 300SB PR.
Old Gallery. http://theartofsound.net/forum/showt...-of-the-70%92s
Location: North Island New Zealand
Posts: 1,757
I'm Chris.
Hi
Here is a design tip for, that you are unlikely ever to find elsewhere
think of what a capacitor is - momentarily storing charge and releasing it.
Inside a speaker crossover the capacitor is either coupling or rolling off frequency
without seeing the schematic 72uf is more than likely rolling off frequency for the
bass driver, or more precisely for the benefit of frequency shelving of other drivers.
Now instead of trying to make a 72uf cap from other values, use 2x 150uf caps in series
thereby obtaining 75uf or thereabouts given capacitor tolerances usually is 10%
here is the interesting part, the midway junction of capacitor terminals + - + - make
this a inductor of suitable power handling, and I would suggest a very small toroid
winding about 20 turns.
Let me know how it goes.
Cheers / Chris
Hi Chris,
I think your assumption is correct, C8 & C6 being the capacitors in question:
ditton44p1.jpg
Unfortunately the Mundorf E Cap Plain only seem to go up to 100uF.
What's the advantage to this?
Darren.
Listening Room.UNDER CONSTRUCTIONTurn Table. Garrard 401 2 Tier Slate Plinth, DIY Hadcock GH242, Nick G modded Lentek, Denon DL-103.
Pre Amp. Croft Micro. Power Amps Quad 405 Mono Blocks.
Speakers. TBC
Home Cinema.UNDER CONSTRUCTIONDAC/Pre Amp. Denon AVC X3700H.BDP/Streamer. Oppo 203 / Apple TV4K.Display. Optoma UHD51 / DIY False Black Window Screen.
Power Amps. 2 x Nakamichi AVP1.
Front Speakers. DIY Baby Celestion Ditton 66. Surround Speakers. Celestion Ditton 11. Subwoofer. BK Electronics P12 300SB PR.
Old Gallery. http://theartofsound.net/forum/showt...-of-the-70%92s
Location: North Island New Zealand
Posts: 1,757
I'm Chris.
So C1xC2 / C1+C2 using 150uf caps is 75uf
Really needs a scope to see change of one circuit
with an inductor and one without.
In a DC circuit one would be right in saying there is not much a inductor is doing
tucked between two capacitors, as the inductor opposes current changing
and there is in theory no current, as the capacitor blocks DC
Then again when first starting a capacitor very momentarily appears as a short
Also very few DC power supply circuits are DC as there is always some 50-60hz
AC residue from rectifiers, hence a series cap and inductor midway combination has much promise
But a capacitor in a speaker is handling a music AC signal , so frequency is involved
Inductors offer low impedance with low frequency and high impedance with high frequency
the opposite of capacitors - so combining the properties of each has merit. The inductor
coming to the rescue of the capacitor, and the capacitor assisting the inductor to a degree.
If I can find some time I will breadboard each and run through a scope with say 100hz
and see what occurs with waveforms.
Cheers / Chris