Phono Stage for passive preamp control


Considering transformer-based passive preamplification. Can anyone suggest a quality tube phono stage with sufficient gain for lower input MC pickups in such a configuration ($2K new or used range)? Don't need volume control on the phono stage, but could go with one that wil bypass the volume control. Am I restricted to a SS phono stage in order to have sufficient gain WITHOUT a step-up device?
4yanx
Yes, probably you are restricted to SS if you want that much gain, without spending a ton of money. If you get a step up transformer, you could do it with a tube unit. Bent Audio makes a set of step up transformers that are high quality, and allow you to make your own high-quality step up for about $400. Pretty easy if you can solder. Or you could get a pair of Jensen transformers for even less, and do the same thing, but I think the Bent ones are better.
The gain issue is really important when using a passive preamp even with SS units. I would pick a unit that is adjustable in case you need to dial it in.

I have a Naim hicap/stageline that I love but really did not work well when I had my Rogue Tempest (great integrated but had passive line stage). Luckily Naim was able to adjust that gain slightly to make a big difference but I had to have them do it. Of course in this situation Naim presumed you are using an active line stage.
I use a Benz PP-1 and a Passive preamp with no problems, unless you want rock concert levels.
I'm not sure about units priced over 1K, but I purchased an Ear 834P and I'm very happy with it. It has close to 70dB of gain, and since it is a tube unit, it is very tweakable. There are many tweaking suggestions on this site and others. Some are as simple as replacing the stock tubes; others more involved. Most of the more expensive tubed units had 60dB gain. Most of the SS units, had more gain. I think the Michell/Trichord Delphini has over 70dB of gain. However, 70dB may not be enough for a cartridge with an output below .4mv with a passive preamp.
Might not the output impedance (generally high) of a tube phono preamp make trouble for a passive preamp? I know that Gordon Rankin of Wavelength strongly recommends an active preamp for use with his Tangent phono preamp, output impedance 1500 ohms. Caution on that score would be wise, I think. Anyway, others have given you a lot of good advice.
You should be able to get a used Aesthetix IO (the basic model) for around $2500. Tons of gain using tubes and sounds great. Designed to drive an amp directly with optional built in stepped attenuators but this will set you back a few thousand more. I use mine with a Placette passive pre and it works very nicely.

I previously had a Pass Aleph Ono that will be closer to $1200 or so and is a fine sounding unit, but not quite as good as the IO.
Maybe you're referring to the Rhea. (?) The IO's I have seen have been about $4K+ used.

I have decided to go with a Bent Audio 102 passive preamp which is seemingly less finicky with respect to impedance matching than perhaps some other units. I am now deciding whether a tube or SS phono stage will best meet my needs. Thanks for everyone's input thus far.
Hi 4yanx, the base model of the IO with a single power supply sold originally for about $5,000 new and can be had for about half of that. The more expensive IO units you have seen have 2 power supplies, and/or are Signature or MKII models, and/or have the volume controls. Going from the base unit to the fully loaded almost triples the price.
I have also seen used IO phono stages at around $2500. But I didn't mention them, because they have no volume control, and when you add the Bent Unit, you are around $3500. If you can stretch up to that level, then you couldn't do any better than an IO with a Bent Audio TX102 volume control.
I have used the following phono stages successfully with a Bent 102S driving a 100K ohm power amp input:
EAR 834P (modified)
Herron
The Groove
Walker Reference

They can all be had (except Walker) below $2K if you are patient. IO is nice too (I used with a resistive passive)
but gets hot and takes a lot of real-estate. Input tubes tend to need changing a lot too. YMMV.
John, thanks for the input, which may benefit others considering the Bent, or for me in the furuter, for that matter. For now, I am currently awaiting delivery of a custom-designed tube/hybrid phono stage being built for me after consulting with Kevin Carter of K&K Audio. Kevin was involved with the design of the Art Audio Vinyl Reference, and the phono stage I am acquiring has very similar featires. Will be posting my impressions in a few weeks regarding it and the Bent 102 after things are up, running, and settled in (if I can ever decide on IC's). :-0
Hi 4yanx
I hope I am not intruding, but I am much curious to know about your experience with the Illustrious arm ?
I am using the Denon 103 and plan to never move beyong its familly line.
So I am interested about givin it a perfec matching arm.
The OL line seems to increase its mass as arm increase in price. I wonder if the illustrious is overkill for the "lowly" Denon familly.
Classical music, small and large, solo voices and choirs, those are the basic on witch my audio search is based.
It seems, the space Deck, the OL, and the Kevin Carter are all great prospect in my search, althought a bitt of a hight price for my purse, but..what do you thinck ?
Hope to hear from you sometime, cheers Pierre
I should step in here, because I am using an Aesthetix Io (Signature, one power supply) with a Bent Audio NOH (TX-102) passive pre right now.

I've found that with my .2mV output cartridge, I need to run the Io at its top gain setting, a whopping 80 dB, to achieve good dynamics with the NOH in my system. This might not be such an issue with higher-output cartridges.

I should mention that the amp is an Aleph 3 driving VMPS 626Rs.

John Chapman of Bent has been very helpful in troubleshooting this situation. The impedance matches should all be fine (Io output impedance is 300 ohms, Aleph input impedance is 10Kohms).

At this point, I have several options:

1. Add volume controls to the Io and dispense with another pre. I'm sure this would sound the best, but would cost me $3600, which I'm really trying to avoid!

2. Change up my amp. Maybe more headroom would help the dynamics. When I had the Io at 72 dB gain (which theoretically should be fine, delivering over 500 mV at the power amp input), I had to run the Bent passive unit with the volume almost all the way up - which doesn't make for the best performance according to John. So maybe my system is really asking for a more powerful power amp. I've considered Ampzilla 2000s, Son of Ampzilla, the Mcintosh MC402, the MC501 monos and (since I'd really like to stay Class A if possible) the Forte 4A and the Threshold 200.... just not sure if those two give me the extra headroom and oomph I need.

3. Just go back to running the Io directly into the Aleph, no volume control. Incredibly inconvenient... and incredible sound!

Bottom line: putting something between your phono stage and your power amp is always going to detract from the sound. So far, the Bent Audio is peforming the job OK for me, but I'm still missing the clarity, soundstage, presence and dynamics of NOTHING.

Patrick
I thought a "Musical Surroundings Phonoemna" would work good for a Passive. I had talked to Paul Lamm who stated it was the best affordable solution to use with a Passive.

They show up used for an affordable price.

It is on my list of components I want when $$ is not an issue.