aguaazul

The quasi bi-amp mode interests me. I wonder if just modifying the VF-100C would work. The M&K VF-100C is basically a ‘Y’ connector with a .015 uF +/- 5% 100VDC cap between. I opened it up, inside is: Channel 1: From the Input from Preamp there is a direct line to the Sub output. From the Sub Output the cap is soldered to the Amp output. Channel 2: From the Input from Preamp there is a direct line to the Sub output. From the Pre input the cap is soldered to the Amp output. Ken suggested that up the value of the cap inside of it to get the proper cutoff frequency. Ken States: “The ST-70 input impedance is 470k ohms, the VF-100 cutoff frequency is around 20Hz (into 470k ohms) which I estimated as the chart only goes to 200k ohm impedance. So, I am not sure if the VF-100 will do much to roll-off the Klipsch's. You might want to consider changing the capacitor value of the two capacitors inside the VF-100 if you want a higher cutoff frequency.” I guess what I am looking for now is a way to calculate the larger Line level cap.

Hey speakerfritz… I wish I had a second set of outputs on the PAS3. It was this connection possibility (RCA thingies) that I procured an M&K VF-100. It has a stereo input from the Pre to a Stereo Output to the Amp and Stereo output to the Subwoofer plate amp of the M&K VX-7 (or any other amp for that matter). I then contacted the inventor of the subwoofer and designer of the sub that I own (Mr. Ken Kreisel) and he was gracious enough to send me a very detailed hypothesis on this type of connection. The M&K VF-100 is basically a 'Y' connector that will show enough _output_ impedance to the amplifier. So I won't blow up my amp. But… If the _input_ impedance of the M&K VF-100 was too low, it will cause the response of the PAS3 to roll off in the low frequencies. This is why I posted this issue to all of you good people. Ken was unable to give me _input_ impedance specs. Another option is to install the Dynaco Doctor PAS3 Mod board and then be able to run multiple amps off of the PAS3 single output. It's a planned upgrade... as funds allow. Ken has offered me instructions on how measure the frequency responses of each different connection scenario with a volt meter and a signal generator or a test disc. What a generous person… like yourselves. This is getting pretty thick... thanks for helping me work this out!

Hey Mustang Guy… cars, horses, guitars… either way, Mustangs are pretty cool… It’s the degraded performance that I am worried about. I have dabbled in the sound engineering arena as a fun summer job in the past and feel I can trust my ears. I will indeed let my ears be my guide. I have been lucky enough to be able to confer with Ken Kreisel himself, the inventor of the subwoofer, the designer of the sub in question and sound engineer master regarding this. I see that in the owner’s manual that it is possible to run the sub and the speakers from the same amplifier tap, the Dynaco ST-70 has 4, 8 & 16 ohm connections. If I remember Ohms Law correctly, I would connect them up to the 4 Ohm Tap. I have another connectivity possibility coming up next…

Thanks for the warm welcome! I’ll try to respond to all responses in proper thread order even though it is against my nature to be proper in other ways ;-) I’m hoping it will be a smooth addition. As far as the room, the Stereo listening space is mixed within the home theater area. With a 17 month old son (Beau) running the house, I took one of those 8 sided outdoor baby cage and created a rock and roll style barrier between my equipment and people (Beau). Room size is 18’ wide where the speakers fire toward and only 14’ deep. Across the back side of the 18’ span is a huge sectional couch. The Heresy’s are 6’ apart measuring from their centers and my listening position is 9’ back dead center. There is the 42” Flat Panel mounted freely on a post type TV stand with glass shelves topping out at Heresy height level. Between them and outside of the Heresy’s are the Home Theater Mains, Polk Audio Monitor70 Series II. These are kinda tall next to the Hersey’s. The fronts of the speakers are 30” from the back wall. I have not delved into the room treatment realm yet as funds are going towards the Crites Crossover rebuilds (E-2), Dynaco Upgrades and Tube Rolling… In the following replies I will delve into the Impedance limitations of the Stock PAS3. Room placement is limited due to Beau & Family. I’ll try to post some pictures of the room as time allows. Thanks Dennie!

Hi Klipsch Community, Long time Klipsch fan, 1st time Klipsch owner and 1st time Klipsch Community Forum post. I have a Stock Dynaco PAS3 Tube Preamp & ST-70 Tube Amp that was tested / repaired to Spec by Joe Curcio (Dynaco Doctor) and I just picked up a pair of 1984 Heresy’s to play with this system just for music only. They lack bottom so I would like to connect up my powered sub, an M&K VX-7. The sub has speaker in / out connections that run thru a speaker level high-pass filter. I don’t know what happens to the signal except for the Low Bass Frequencies less than 80 HZ are filtered out from the Heresy’s. My question is will the Tube Sound from the Amp be degraded in the above 80 HZ range running this setup? Thanks for your time and info!