Aaah, ok. Those aren't dip switches, those are the connectors for the wires going to different portions of the ESL panels.
The two attached pics should give you the info you need to make sure both of your speakers are wired up correctly.
The wires coming from the panels should have tip plugs that fit the connectors on the PC board.
http://www.diyaudio.com/forums/planars-exotics/230436-acoustat-panel-connections.html#post3378456
Let us know if they are before we start trying to chase down reasons for the measurement difference.
The two attached pics should give you the info you need to make sure both of your speakers are wired up correctly.
The wires coming from the panels should have tip plugs that fit the connectors on the PC board.
http://www.diyaudio.com/forums/planars-exotics/230436-acoustat-panel-connections.html#post3378456
Let us know if they are before we start trying to chase down reasons for the measurement difference.
Attachments
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Unless the two frequency response graphs are purposely vertically offset for clarity, it looks like one speaker is louder at all frequencies. I would start my measuring the bias voltage and making sure it's the same for both speakers. The method for this is attached, as well as the method for adjusting same. If you still have low bass output, I would next check the two largest power resistors on the HV board - one of them may be open or way off value.
Andy I have a great working pair of 1+1s with 2 powered subs. Would it be possible to change the High pass cap (57UF) to a lower value and bring the frequency cutoff to approx. 70hz.? Want to match my subs better and at the same time take some low end stress off the panels. Don't like to use active xovers just more junk in the signal path. Want this to be elegant and highest quality sound output. If so what is your educated guess on the values to start with ?
Thanks,
Andrew Sterling
Thanks,
Andrew Sterling
That won't work at all. That capacitor is a high pass into the HF audio transformer, and altering it's value won't affect the low frequency cut-off of the speaker. You might try inserting a capacitor in line with the power amp's input (not output!). This is assuming the subs have their own amp. I do this with my Spectra 4400's to roll them off at -6dB/octave below 80 HZ. The value of this capacitor will be quite small, and therefore not too expensive even for a quality unit. The value will depend on the amp's input impedance and the desired cut-off frequency, according to f = 1/(6.28 x R x C), where f = freq in hertz, r = input impedance in ohms, and c = capacitance in farads.
There are NO dip switches in the speaker, at least not as originally configured. If someone has added some, I suggest they be removed, as no dip switches are capable of handling the voltages involved.
The rear stator wires are in the BLUE group, and the front stator wires are in the WHITE group. See the diagram posted above to see the complete Spectra color coding scheme: all should be clear if you follow the diagram.
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I don't calculate that figure: I get 219 Hz for a .022-uF capacitor. Based on a 33K input impedance, and a -3dB point of 70 Hz as mentioned in your previous post, you would need a .068-uF capacitor. Rearranging the formula to solve for C, use C = 1/(6.28 x R x F). Remember C will solve in farads, not microfarads. Once you solve for C, move the decimal point six places to the right to get microfarads.
The only thing I can see that might be confused with a bank of dip switches is the 8 pin op-amp identified in the attached pic.
I also circled the trimmer potentiometer used for adjusting the HV bias level using the guidance provided by AAMan in Post#1622.
As mentioned in post#1622, if the difference in level exists at higher frequencies as well as in the bass, it is likely a bias problem.
Your plot only extended to ~200Hz, so it is not clear if this is the case or not.
Attachments
I'm not sure if the 33K input impedance is based on a measurement, or just from the spec sheet.
Sometimes the actual input impedance is significantly different from spec due to late design changes, etc.
Attached are some trend plots that might be useful, using standard capacitor values for 3 different input impedances.
Attachments
6600
I am in the process of building an interface for my recently purchased 6600. I would like to know if my Quicksilver V4 mono blocks would have any issues driving the 6600's
Specifications:
Power Output 170 watts into 4 or 8 ohms from 20 Hz to 40 KHz
Power Bandwidth 18 Hz to 80 KHz
Peak Power 210 watts at 1 KHz
Input Sensitivity 1.5 volts
Input Impedance 100 Kohms
I am in the process of building an interface for my recently purchased 6600. I would like to know if my Quicksilver V4 mono blocks would have any issues driving the 6600's
Specifications:
Power Output 170 watts into 4 or 8 ohms from 20 Hz to 40 KHz
Power Bandwidth 18 Hz to 80 KHz
Peak Power 210 watts at 1 KHz
Input Sensitivity 1.5 volts
Input Impedance 100 Kohms
Dear Acoustat Answer Man. You were right on the money thank you. The left unit measured exactly correct and the right was well down. I turned the pot to the maximum but only got 74 volts (method #2). Left reads 75 Volts. This is a small difference so I guess it will be ok. What can cause this loss of voltage?
Thanks bolserst, I received the transformer and it matches your image. Onto next step in building the interface.
SPW-1 cabinet measurements
Hi,
Looking to put together an SPW-1 cabinet from scratch. Have all the drivers
and crossover (someone parted one out), but need the cabinet dimensions
(just the box between the hardwood end caps). I found an "about"
23 x 17 x 19 estimate from an old sale listing. Port diameter and length
would be helpful as well, as the drivers (tested on WT2) don't model
"normally" in bass reflex cab sims, so I'm assuming they (drivers and cab)
were designed/tuned to work with the Spectra models (vs. being a generic
sub).
Have an old 1+1S pair that this might work reasonably well with.
thanks and regards. (tried PM to likely member here, but no recent activity)
[also wik pairs of 1+1 and recently acquired factory-updated 2+2]
Hi,
Looking to put together an SPW-1 cabinet from scratch. Have all the drivers
and crossover (someone parted one out), but need the cabinet dimensions
(just the box between the hardwood end caps). I found an "about"
23 x 17 x 19 estimate from an old sale listing. Port diameter and length
would be helpful as well, as the drivers (tested on WT2) don't model
"normally" in bass reflex cab sims, so I'm assuming they (drivers and cab)
were designed/tuned to work with the Spectra models (vs. being a generic
sub).
Have an old 1+1S pair that this might work reasonably well with.
thanks and regards. (tried PM to likely member here, but no recent activity)
[also wik pairs of 1+1 and recently acquired factory-updated 2+2]
The exact bias voltage is not critical, and there will always be unit-to-unit variations. The beauty of the Ultrasonic bias supply is that it is adjustable, and therefore those variations can be compensated.
Of far greater importance is that both speakers have the same bias voltage. Therefore, if the maximum you can get from one speaker is 74 volts, then set both speakers to 74 volts. This will ensure equal volume from both speakers.
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I can't be of much help on the SPW-1. That unit was designed and manufactured at Rockford's Carbonneau facility, with only the final design approved by the golden ears at Acoustat. The drivers were custom designed and manufactured at Carbonneau, and I was never privy to the details or specifications of the drivers, crossover, ports and enclosure.
I can tell you that the SPW-1 was a HUGE improvement over the woofer module supplied with the Models 1 or 1+1S.
