Phono Stage Choices

[galibier_numero_un]

A private dialog with Cknicker prompted me to start an Electronics Forum. I'm compiling our three e-mails here, for the purpose of carrying on the remaining conversation here, where we can subject this dialog to the scrutiny (and for the benefit of) all …

This thread could potentially live on the "Building Your System" forum, but I think that it's more likely to be seen (and commented on) by more folks if it lives over here.

I haven't exchanged emails with you in a while and just wanted to say thanks
again for hooking me up with Dan, Doug, and Paul. My listening session at
Doug and Paul's was what I could almost call a life changing experience. In
addition, we are scheduled to get together at Dan's shortly (in a couple
weeks time) for another session (this time to evaluate the Gavia). I expect
this will be another eye (ear) opening revelation.

Now the question(s):

After hearing the Alaap and Lectron at Doug/Paul's, all I could think of was
trying to find a way to get an equivalent set of electronics into my own
system. I have been browsing the web and have bumped into your name
regarding the "Hyper-it" and other tube related DIY info.

I would love to (eventually) own an Alaap but until I can find the $$$ to
fund the other things on my list first (Galibier/Teres/equivalent), it'll
probably be a long wait. As a result, I am hoping that going a cheaper route
(DIY preamp) might give me something closer to the end goal and also be a
fun learning project at the same time.

1) Can you give me some advice on how to get started down the DIY preamp
tube path?
2) What are the things I'll need to get (do I need an oscilloscope?) once I
need to do any testing?

Thanks for any help you can give,
Chris

I just caught this before turning in for the evening. The modified Super-It
(a.k.a. Hyper-It) is pretty cool, but the circuit boards are quite fragile.

If I were doing this today, I would definitely go with one of Jim Hagerman's
Coronet II kits. You'd need a step-up for your Koetsu, 'coz it's MM level
gain. Dave Slagle (Intact Audio - http://www.intactaudio.com/) will wind you one
specifically for your Koetsu. Frank Schröder loves Dave's work.

For a bit more money (assuming you need a line stage), I'm becoming very
smitten by Mike Sanders' (Quicksilver Audio) new full function preamp ($3K
.. working up there in price). I'm exhibiting with Mike next week, and
have gained incredible respect for him.

My view of Quicksilver (before getting to know him) was of a company that
made honest, bullet-proof products at an incredible value. What's not to
Like about that? Well, I thought that maybe his tastes were a bit mainstream.
As I hear the evolution of his work, I am gaining more respect for his work.

More to follow in the morning.

Nitey-nite,
Thom

Thanks for the info, Thom.

I've had a look at the sites you've pointed me at am still a little
puzzled as to what I should expect in the end.

Having read the Chris Brady Tube Haven stuff (where there are references to
the Loesch and Super-It designs), I was hoping to get to the end goal of
having a "Holy Crap, what a sound!" system while making it cheaper due to
the fact that I'm doing all the design/implementation myself (though
trading off my time vs. cost).

Am I being completely naive? Am I likely to get to that same expectation
by going with a kit form?

One other question: are the Quicksilver products in kit form?

Thanks again,
Chris

Hi Chris,

I'm going to transcribe this conversation over to the forum, because I think it is of general interest. Let's continue the discussion over there.

All of us with the possible exception of Chris (haven't been at his place in some 7 years), have given up on the Loesch design. I believe Chris may also have given up on it as he has of late been exhibiting with the Artemis phono stage these days.
When John Atwood (One Electron, Artemis Labs) and Lynn Olson swooped into Colorado three years ago, our local listening group came to realize that there are quite a few highly regarded designs which have terribly slow circuits - slew rates that can't keep up with the musical transients. Raul has correctly commented about this on Audiogon's Analog Forum.

The Loesch phono stage is one of these slow circuits. This manifests itself in ways that mask themselves as groove distortion. I remember the first time we swapped out the Loesch unit at a friend's house for one of the Artemis Labs phono stages. I use the Artemis as an example because I have quite a bit of experience with it. The Artemis is quick but the Alaap is quicker yet.

Well, when the Artemis was slipped into the circuit, what I thought was a mediocre cartridge alignment ended up being mediocre electronics. The supposed tracing distortion ceased to exist. The Loesch is dated, and quite a few individuals have moved beyond that - and not necessarily at extreme prices. I'm still learning to identify (and attribute) sonic artifacts to the correct component. This lesson learned some 3 years ago was most instructive to me.

Quicksilver Audio (http://www.quicksilveraudio.com/) makes finished products - not kits. Mike Sanders (like Jim Hagerman) gets it and has always had solid engineering. I don't think Mike has photos up on the website yet of his new full function preamp. He's just getting the final metal work back from the anodizer … in the nick of time for next week's Audiofest. I think your decision will be somewhat influenced by whether you have a line stage that you like. The Quicksilver is a full function preamp (includes line stage, source selection switching, and dedicated headphone amp section). It's very nice, and it's $3K price point is extremely fair, but it's still a non-trivial expenditure. I realize that this might blow your budget.

The Hagerman Coronet II comes in kit and "half kit" form (http://www.hagtech.com/cornet2.html). Kit is just what it sounds like (last time I checked). Jim's "half kit" concept is unique, in that you purchase the PC board plus plans which include a bill of materials with Mouser and Digikey Electronics parts numbers (order directly from Mouser and Digikey Electronics). This saves him the burden of inventorying parts and the savings (for having to swipe your credit card a couple more times) is passed on to you.

Most importantly, you are not being naïve. The right component, designed by a competent guy who *also* has a musical sensibility about him will most definitely get you most of the way there. The Hagerman and Quicksilver gear fits this bill nicely. Don't mess with the Hyperizing a Super-It.

Cheers,
Thom

Thanks again for the very helpful information, Thom. Having listened to Doug and Paul's Alaap, I now consider this to be the finest preamp I have ever heard (though admittedly, I haven't heard all thatmany). Eventually, I'm going to save my money to buy that (if I don't find something better at a cheaper price). Until that time, I'm all for tinkeringaround with DIY designs/implementations so long as it doesn't eat too much intothe bigger budget items. The items on my current list are: Gavia/Teres, Triplanar/Schröder, Alaap, Lectron, ...). One final question (I won't hold you to it): if you had to pick onedesign to play around with (i.e. DIY) what would it be: Lynn Olson, Hagerman,Super-It, ...

Thanks again!
Chris

Hi Chris,

Forget the Super-It ... not only because at this point, you're likely to find only ones with trashed circuit boards, but also because Jim Hagerman's Coronet (both I and II) are just plain more musical.

Dave (salectric) will likely comment on his and his son's projects.

The Artemis and the Quicksilver come next, with me having a marginal preference for the Quicksilver - not only because you get a line stage for the same price, but because it makes the Artemis sound a bit mechanical in comparison. I emphasize 'a bit'. They're both fine units.

I'll be in Michigan shortly, and will get to hear an Alaap in a different context from when at Dan's (when the driver tubes on his amps were misbehaving). A one evening listen at Mothra's (where are you?) points me to the Alaap being very fine indeed.

Cheers,
Thom

[ckniker]

First of all, thanks to Thom for moving the mail thread here (and for the incredible time he must put into his responses).

Just to summarize what I'm trying to get out of all this (Q/A):

1) I'm an electronics/analog beginner (w/ an Comp. Eng. degree!)
2) I've seen the light! (i.e I've heard the Holy Grail)
3) Until I can afford the Holy Grail, I'd like to try building it (via DIY)
4) Any advice on (the ultimate) circuit design to start implementing that will get me close (and helps to teach me what makes the Holy Grail sound so great) ?

I'd love to hear from anyone who has advice on how to get started. I'm not fearful in tackling new projects.

Chris

[Salectric]

Chris,

I think the Cornet would be just the ticket for you. It sounds very good, it's easy to build, and it's pretty inexpensive. What's not to like? The Hagerman circuit board makes the assembly quite easy and the results are more predictable than a true DIY project. I built mine back when it first came out, back before there was a I or II version, and I still pull it from time to time. You can also tweak the sound of the Cornet by changing components such as the coupling capacitors, for instance.

I replaced the Cornet (and a couple of true DIY designs) with an Artemis PH-1 which is indeed a better sounding phono circuit, but it'a also a lot more expensive.

After building a Cornet, if you want to try something more ambitious, take a look at Stephen Robinson's design, which is described in detail on his excellent website:

http://www.izzy-wizzy.com/audio/preampnew.html

Stephen's phono stage is several steps better sonically than even the Artemis. It's now my regular phono preamp.

The Cornet is not the only option, however, for a starter phono stage. Three others that come to mind are: (1) the Bottlehead Seduction, (2) the Blueberry Tercet, and (3) the AES PH-1. Each of these is a kit and each has its fans. I haven't heard any of them so cannot offer any opinions on sound quality. You can find information on each of these by checking the archived posts at Audio Asylum.

Dave

[ckniker]

Dave,

Thanks for the suggestions, this is precisely what I'm looking for. Both you and Thom have suggested the same path (Hagerman first) so I'll probably go with that route first.

Now a quick question:

I've had a look at the Hagerman Clarinet (Linestage preamp) schematic (and pictures). Excuse my ignorance, but it appears to be only a single channel design (with a balance control!).

Am I missing something or what's up with that?

Chris

[galibier_numero_un]

Hi Chris,

Jim has a good forum over on Audiocircle:

http://www.audiocircle.com/circles/index.php?board=52.0

It has quite a bit of dialog relating to tweaking and modding.

I heard his Clarinet line stage in his room at RMAF last year - at least I think he was showing the Clarinet.

Jim was running a Trumpet phono stage each time I visited, and my sense is that the Clarinet is more in the Trumpet's class of component. I didn't sense the Trumpet being held back by the Clarinet.

From the photo and the text on his website, the Clarinet is stereo and allows for switching three input sources, along with having a balance and a volume control.

Jim can answer your specific questions.

I too am curious to hear / build Stephen's phono stage. I trust Dave's ears. He's very picky ... in a good way. You definitely don't want your first, full DIY project (as opposed to a kit) to be a phono stage however. Chasing down noise issues will drive you crazy.

Cheers,
Thom

[ckniker]

I found the source of my confusion:

The tubes are "double" triodes. I presume this means both Left and Right channels are fed through the same tube.

In the pictures of the completed Clarinet I saw only two tubes in the chassis (not including the large one for the power supply). After looking at the single channel schematic, I also saw two tubes in the circuit. I (incorrectly) figured that there must be FOUR tubes needed for both the Left and Right channels.

Other questions:
1) Doesn't this introduce cross-talk (L/R interference) issues?
2) Does this simplify tube matching?

Chris

[galibier_numero_un]

HI Chris,

In this simplified schematic:

http://www.hagtech.com/images/clarinetschem.gif

You're viewing the signal path for one channel. This is commonly done (showing only one channel) to keep drawings less cluttered.

The one channel is using both halves of a single tube - a dual triode being used as two tubes. The second channel is using both halves of a different triode, so there are no cross-talk issues.

In my limited experimentation with line stages, I never had any success in sharing the two halves of a dual triode across two channels. Perhaps Dave or Stephen can comment further. Whether this has to do with cross-talk or other issues with this shared electron cloud coming off the heater is outside my knowledge realm.

Cheers,
Thom

[izzy wizzy]

I'd agree with the posters here regarding a starting point for a DIY phono stage in that it would be wise to start with one of Jim's kits. After that, then maybe you could branch out with one of the other designs which tend to be not as well documented.

Dave built a version of one of mine, an earlier one from the design I currently use and I think ended up with a variation I never built. I'm not quite sure how far you got with it Dave? I think the version he built is a good starting point IF you don't want to go as far as I did with transformer coupling throughout. It's something I'm still working on.

Steve Bench has a highly regarded design which is well documented; his LR EQ design. There are many choices out there if you decide to go the DIY route.

Stephen

[izzy wizzy]

As for sharing valves between channels, it's not something I do. The main reason is, I don't like to be constrained on layout by having to use two devices in one envelope.

There is an interaction between the cathode and the heater even in IDHTs which could be another reason not to do it. Sharing a valve between channels seems to me to be done for economy reasons.

If a dual valve is used, then if you wire up say the first half in one channel and the 2nd half in the other, then it is possible to swap them over in 10,000 hours time or so and get another 10,000 hours out of them again. The Artemis phono does this.

As for valve matching, it's not something I worry too much about. Maybe I should and I think if you were taking a design to its ultimate conclusion it would be a good thing. With seperate envelopes between channels, it would be easier. For some of the freakier valves, I do match them but that's only because the sample to sample variation can be big however they tend to be singles not duals.

Stephen

[ckniker]

Stephen,

It's funny but I was just reading your website/preamp design when I noticed that you posted here.

Do you care if ask you some questions? Some will be newb-ish, admittedly, so I can understand if you don't want to waste your time. I'll try to limit them.

If there's a more appropriate forum, I'll post there.

Chris

[izzy wizzy]

Chris,

It's good for me to have people ask questions. It has in the past helped me make it better and find mistakes

Stephen

[ckniker]

Great, I will open up a separate note and start asking when I have done more studying of your design and have a few more questions saved up.

Thanks,
Chris

p.s. By the way, (excuse my ignorance) but what does HT (and LT) mean? These are referenced quite frequently.

[izzy wizzy]

HT is high tension - the main DC high voltage power supply anything from say 100V to 400V in preamps. Can be way way more for power amps. The dangerous bit that can kill.
LT is low tension - the heater(s) supply typically 6.3V or 12.6V in preamps

[Jim Hagerman]

As for sharing valves between channels, it's not something I do

Hi guys! In a cost-no-object design I would agree.

In my single-ended phono and line stage designs I run both channels in one glass envelope of a dual tube. Sure, on the surface it seems like a bad idea. However! If there is anything you can compromise on, it is crosstalk.

Think about it for a moment. Just how much LR isolation does one get from a cartridge and LP? At best it is 30dB. Usually less. And so I ask, what good is 80dB crosstalk isolation in a linestage? It means absolutely nothing. It is a number for specification-oriented designers to chase after.

What is worse? That's an easy question to answer. It is far worse to run two sequential gain stages in a single envelope. Why? Because it creates a huge opportunity for positive feedback. Especially with something like a 12AX7. Two inverters in a row with inputs and outputs right next to each other results in stability issues, even to the point of oscillations. And then one tends to ruin sonics by fighting instability with unnecessary modifications. Sure, you can get away with it, but overall I rate this approach as more dangerous.

jh

[restock]

Great thread!! I just joined the forum and thought I'll have to throw some more questions out there (especially for Thom).

What do you think of the K&K phono stage kit? I am planning of upgrading my Wright WPP200C phonostage and have been considering building the K&K kit

Alternative Allan Wright has a great kit as well - the SVP1 full-function preamp. Going full function would be nice as well, since I have some more funds available then For full-function preamps, I have been considering the SVP1 as well as the Shindo preamps (Monbrison, Aurieges).

Any thoughts on the above are greatly appreciated.

With best wishes,

Rene