Voltage mode vs current mode phono stages

@lewm , I already have the program so, yes I plan on trying it. But, I am ordering the RIAA board as back up. I should be able to do it with the equipment I have now as long as I do not get into a jitter war. Channel D recommends a combination ADC/DAC using the same clock. Their favorite is the Lynx HiLo. Nice unit but I would rather not have to buy one. I'm pretty sure digital correction will sound fine. The question is how much more of a pita is it going to be playing records that way vs the old fashioned way. You know I will be happy to forward my opinion.

Peter Ledermann related to me directly that his MI cartridges will not work well with a current mode phono stage. The high frequencies will be rolled off. He did not give me the reason why but I am sure it has something to do with inductance and impedance.

@lewm , I think Fremer sleeps with his CH Precision. Nice unit but way more stuff than I need. I prefer simple.

I will be able to address this better in a while as I ordered a Channel D Seta L Plus which can be run either way. I plan to run it in current mode because of the theoretical advantage, the most important one is less interference with tracking. Every generator is also a motor. With less impedance this effect is more limited. 

@ledoux1238 , I think what you are hearing is a frequency response shift. Whether or not one is more or less accurate than the other is up for grabs. If I have two systems and turn the upper midrange and treble just 2 dB on one of them everyone listening will prefer the brighter unit even though it is "less accurate." In my own system I intentionally boost the bass because I feel it gives you more of the experience of a live performance even though it is "less accurate." This is why everyone has the right to listen to whatever they like. Unfortunately, that might make someone else cringe. My point is what a system sounds like is an extremely fast moving target. Interpreting what other people say is virtually impossible. There are characteristics which are more definable like those of the image. 

@ledoux1238 , Yes, I will report on what I think in my system. That is a lot of stuff to cram into a Lino C! I was going to get a Lino C but it turns out the Seta L plus is a better unit even though it is less versatile. 

Most of the differences we hear are in amplitude variation across the frequency band, bright, dark, warm, vivid are all caused by frequency variation to which we are quite sensitive. These variations can be caused by intension, our systems, resonances anywhere and acoustics and are way more prevalent than other errors such as distortion and group delays. 

@lewm , IMHO the Grails are horrendously over priced. Looking at the internals the construction quality is not up to modern standards. As an example the boards are through hole not surface mount which is considered to be better. 

The Seta L Plus has significantly better construction, a better power supply and comes in at $10K. It's only down sides are it is not very versatile having only one input and switching between current and voltage mode requires going into the unit and removing or replacing a jumper. You would have no problem with that and I greatly prefer the simplicity.

@lewm , I looked at the BMC and read Fremer's review. The current price is $4800.00 which is not bad at all. They are built in China.

Comparing the BMC to the Seta + is relatively easy in regard to their physical attributes. The BMC is very nice looking although some would argue that the on-off switch(that huge knob in the center) is a little over-baked. The Seta + is industrial looking in comparison. Inside the units is a different story. The BMC uses through hole phenolic boards and the Seta + SMD construction on fiberglass boards. The BMC uses standard regulated power supplies (good ones) while the Seta + uses  lead acid batteries and a charging system that disconnects from the unit when in use, perfect isolation. The Seta + is made in America and costs over $9K with the optional RIAA board. Made in America covers the price differential. 

Fremer reviewed an older version of the BMC and liked it very much. He also reviewed the the Seta's little brother the Lino C which he also liked very much. I suspect both units are excellent phono stages and would have been SOTA if they were three times the price. I am in the same boat Lew is in. I really like the idea of a current mode phono stage but am not going to spend silly money on the CH Precision unit. I do not need the added complexity and it is a very complex unit and I do not feel like spending money on complexity. But I would bet dollars to donuts that blinded, few of us if any could reliably tell the difference between the three stages. Mr Fremer would argue with that, but he has better hearing than I have. 

@lewm , what makes the BMC you favorite?

@atmasphere , HI Ralph! It's been a while. You been on a ride yet? My wife and I have new bikes this year. The drive trains are somewhere between New Hampshire and Italy.

Very true. I have worked on SMD boards with a needle point on a Weller station using a magnifier lamp, 10X I think. If you remove all the solder with a wick and have things nice and flat you can tack the component down with a dab of thick cyanoacrylate. When it dries solder the contacts. 

Personally, I'm a traditionalist and prefer the point to point wiring in your amps, a thing of beauty. Makes me want to wire a set for myself:-)

@lewm , you still have not told me why you gravitate towards the BMC. The quality and type of construction used in a unit are important indicators as is circuit design. As far as sonic performance is concerned, it is much harder to get a bead on it and frankly all great phono stages should sound exactly the same. We usually only get to hear them after the purchase. I will go with the best construction every time for the type of unit I want in this case a Current mode phono stage.  

@rauliruegas , I can not disagree. I am taking a risk with the Channel D unit but then I hardly ever get a chance to audition units before I buy them. I do my research and cross my fingers. Rob Robinson is a very bright engineer who is totally bonkers over vinyl. His construction methods are right up to date and you can use his units with digital RIAA correction which again theoretically has its benefits, theoretically. We shall see. If it does not I'll sell it and move on. 

I have this acre of land right in the middle of Central park:-)

@ledoux1238 Thanks! I did not know he had reviewed it. @rauliruegas check out ledoux's link. I know you are into SMD and ultra accurate RIAA circuits.