Switching on a push pull amp without speakers connected is fine as long as the output valves are triodes. Different matter with other valve types like pentodes. SE amps don't mind at all.
Switching on a push pull amp without speakers connected is fine as long as the output valves are triodes. Different matter with other valve types like pentodes. SE amps don't mind at all.
a picture helps
Here is simplest 1st order form, the cap is stopping the tweeter getting low frequency (would be harmful at power), so it can produce nice sounds in it's comfort zone and the inductor is stopping the woofer trying to play higher frequencies at which it is crap.
The crossing point I choose is 1000Hz (what Tannoy use on 15" HPD/Golds etc...
As this is the most basic crossover the ramp up and down slope are shallow 6dB / octave.
For steeper you need more components.
Going up the scale to 4th order you get 24db/Octave and use lots of components = expensive and signal sapping.
This might seem like a good idea as the woof does less tweeting and the tweeter less woofing - should be good, but pushing the precious signal through all these chokes and caps does sap detail / clarity and dynamics so they use as few as possible / trade off.
I used 2nd order 12dB/octave as a compromise...
For a 3 way you get
You can mix driver impedance and the crossover compenent values vary to take that into consideration.
Here the mid band is both avoiding receiving too low or too high so you have both in there - unavoidable.
You can choose drivers that tail off naturally sometimes - the JBL2435Be's I use as upper mids go to 9000-10000Hz and then drop off naturally so no need for the components to pull them down as they are doing that anyway. Sometimes you can do the same with woofers just rising naturally - sometimes not as they comb or just sound bad.
Here's the tool I use
http://www.erseaudio.com/CrossoverCalculators
There are also L-pads to reduce the volume / gain of a more efficient driver - devils work as they sap clarity / dynamics. I tried these as a stop gap but doing it at line level is much better and more controllable IMO.
And Zobels to stop a drivers impedance raising with frequency. I use those on the bass and sub bass drivers in my system.
You can of course use Digital Signal Processing and get 48dB / Oct slops, L-pads, time delays to align drivers and more, all done in the digital domain but it def needs an amp per driver pair and converting your analogue signal (should you have one) to digi and back again is not the best thing to do to it!
Some use a cheapie such as the http://www.behringer.com/EN/Products/DCX2496.aspx
play around measure and get the crossover points they like and then build a passive one - as they sound better than the 2496.
You can get expensive ones like http://www.deqx.com/ for several thousands. £6.5K to do my 5 way horn system - gulp! Some can do room correction too...
I tried Anti-mode 8033 on Reid's recommend and like it but that is only messing with 10-150Hz and it does not muck it up with DAC and ADC at those frequencies and there's little else to can do.
Fun and Games.
Depends on the PP amp Ali, not all will complain...
Listening in a Foo free Zone...
Only a Sith deals in absolutes.
Welcome back, Neal - long time no see!
Marco.
Main System
Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.
Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.
Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.
CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.
Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.
Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.
Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.
Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.
Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.
Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!
Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!
Man oh man look what I started...
Jeff :UBERTHREADKILLER
Hi Steve,
Your excellent pics have disappeared, mate (now getting a "Temporarily Unavailable" message) - makes the thread look rather untidy...
Can you fix it?
Marco.
Main System
Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.
Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.
Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.
CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.
Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.
Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.
Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.
Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.
Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.
Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!
Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!