Phono Stage upgrade to complement Dohmann Helix One Mk 2

@lewm , all my filters are digital. I can select any slope and any frequency at 1 Hz intervals and I can make adjustments on the fly from the listening position. This is TOTALLY different than analog filters. 

@rauliruegas , I have heard you say on multiple occasions that digital reproduction is not just a little, but far more accurate than analog. Have you changed your position? I have owned Velodyne Subs and have listen to some of the more current models. I would never have one in my system. There are many great woofer drivers out there now. The differences in the good ones are relatively minor in comparison to the differences in enclosures. There is not one commercial subwoofer I would have in my system, not one. Not even the Magicos (to effin big!). But in order to have a chance at being uncolored the sub has to have two drivers at opposite ends of the enclosure operating in phase. This keeps the sub from shaking at volume which causes distortion. The only commercial subs that do this are the Magico Q Series, Some of the KEFs and the ML BalancedForce series. The best way to avoid driver distortion is to use large ones of high quality. The amps used in any of these subwoofers are compromised because they can not produce significant amounts of heat. They also have to fit within the subs and the manufactures want to keep them small. IMHO passive subwoofers with outboard electronics are the only way to go. I double darn guarantee that not one subwoofer plate amplifier can produce the bass of a JC1. Unfortunately, this is a much more expensive approach but that is life. 

Now as for as my turntable is concerned. If I remember correctly your most significant concern with phono stages is an accurate RIAA correction. My phono stage is connected to a Lynx Hilo, a studio ADC, DAC router. The phono stages output is set to flat (no RIAA correction) and the correction is performed by a program in my audio computer. It is way more accurate than anything you can do in the analog domain, very cool. You should try it or are you going to be one of those stuffy analog only guys. Good luck trying to find an analog record now a days.

Mijo, my question was specifically what are you using to provide digital domain filtering, that is, what brand and model? Thanks.

Here on Audiogon and elsewhere there are always a plethora of good high power solid state amplifiers for sale pre-owned at prices far below the cost of a new JC1. You’ll say the JC1 is best and I’ll say we’re only talking about the lowest 2 octaves of low bass. I’d look for a Threshold or Krell or any of many other good choices. In fact one might find a used JC1. I do also like the force cancellation idea.

Dear @mijostyn  : I did not change my way of thinking on digital reproduction. The issue is that I don't mix analog / digital at same time.

When I'm listening to analog I want to listen the analog alternative colorations and when I listen to digital I like to hear the digital color.

You are totally immerse in digital and nothibng wrong with that because it's what you like it. Maybe in the future I could be immerse in digital too but not now.

Analog has its own and specific color and digital too but way different. drbond is now thinking to mix it, fine for him.

As I already posted your holly grail is just yours and you are enjoying, good.

R.

holmz , Not at all. You ever tried an analog crossover on ESLs? Wel I have, several ones and they all turned out to be awful in the end. You can do it but there are far superior ways

^Nope I have not.^

I have only tried the Vandy HPF and their sub… and it is the older one.
(not old when I got it, but it is now.)

But yes the three options are:

1. A Vandy like HPF cutting the main L/R and a sub that account for that
2. The same HPF (or a capacitor) and do the bumping up of the sub digitally using another cable from the preamp like RCAs.
3. A digital XO and the running the HPF to the main L/R and LPF to the sub(s)

In any case reducing the low frequencies to the main L/R is “always” beneficial - unless one never has low notes, DC offsets or subsonic rumble freqs.

drbond, In most cases both the HPF and the LPF built in to a high grade commercial sub would be ACTIVE filters, not the same as just inserting a capacitor in series with your main ampifier, which is a PASSIVE filter. The difference is that in an active or electronic crossover, usually there are some active gain components that correct for insertion loss (remember insertion loss from way back up this thread?). A side benefit of an active (electronic) crossover is you don’t have to be concerned too much about the input and output impedance of the driven and driving devices. In other words, you don’t have to worry about the input Z of the amplifier you are connecting to. Remember I mentioned that your amp with a 22K ohm input impedance needs about 0.1uF capacitance to roll off below 80Hz? With an active crossover set at 80Hz, you could buy a new amplifier with a very different input Z and not have to change anything. Also, you can just twist a knob to experiment with a lower or higher HPF point, if 80Hz is not satisfying. With a passive filter, you would have to re-calculate the capacitance and install the new value.

Also, your thinking about the cello frequencies as you outlined it in your post at 12:47 pm today is a bit off target. If the main speaker and subwoofer are well adjusted, then you will not hear a problem. Of course, that takes some thought and effort to get right, since as you say the cello operates right at the crossover frequencies one is most likely to use with a full range speaker + sub, 60 to 80Hz. Like everything else in life, there is no free lunch, which is why I have resisted subwoofers with my SLs even though I acknowledge the potential benefits. (I’m rethinking the issue as a result of this thread.) One point to consider is that subs are very re-sale-able, if you end up disappointed. There is a big market among home theater gurus. Finally, with a passive 6db filter, the chosen crossover point represents a frequency where the attenuation is -3db; it’s not flat down to the crossover point. Thus, another octave down is -9db, not -6db. Not so with most active crossovers.