The short answer is no, I never talked to them. My unit is out of warranty anyway, and there’s gobs of room for the caps inside, so I just went ahead and did it myself. I understand why they chose overly large value capacitors; they are trying to account for users who might mismatch the unit to downstream devices.
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Lamm not "lamb" in the last line of my post above.
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Dhcod, you are certainly entitled to your opinion, regarding the superiority of the Lamm phono stage over the steelhead. My opinion is different. I have heard them both, and I do think the steelhead is a bit superior, although not by much. I certainly think the question is debatable, and not a certainty. A few things to keep in mind regarding the Lamm phono stage are as follows: it uses an internal step up transformer for moving coil gain levels. And maximum gain is 60 DB. The step up transformer has a 1 to 20 step up ratio, so you must take care to use it with moving coil cartridges that have a very low internal impedance, 10 ohms or less is advisable. Second, it has a rather high output impedance of 2800 ohms, I think. Or certainly in that ballpark. That means one ought to be careful about mating it with a downstream line stage, although most linestages would probably work OK. The Steelhead has three pairs of phono inputs and does not require a step up transformer in order to accommodate moving coil cartridges with low output. The total net gain is 65DB, so a little higher than the Lamm. Further the Steelhead has a built in linestage and costs a few thousand $$$ less than the Lamm. like I wrote earlier, in my opinion, the major factor that holds back the steelhead from being as good as it could be is the mediocre coupling capacitors used at the output, which are easily upgraded. With upgraded capacitors, I think one would find the steel head to outperform the lamb, clearly.
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Using what with a SUT? The Steelhead has three pairs of phono inputs. Two are for MC cartridges, and one is for MM. You can choose up to 65db of phono gain. So there would be no need for a SUT with most LOMC cartridges down to about 0.2mV output. (I actually used mine successfully with an AT ART7, which outputs only 0.12mV, but that is probably owing to the fact that the Beveridge amplifiers are "sensitive".) Right now I am using it with Koetsu Urushi, and the attenuator is not even at its midpoint for very high SPLs in my large basement room. But maybe you did not refer to the Steelhead.
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Tomic, any time you wanna talk Beveridge direct drive amplifiers or spkrs, you can pm me. It’s a labor of love.
I’ve probably got a few thousand dollars worth of spare tubes, capacitors, resistors, and even transistors in my basement workspace. For the Steelhead I am using 10uF Dynamicaps between phono output and attenuator. Between attenuator and outputs to the Bev amps I am using two 2uF polystyrene caps in parallel, for a total of 4uF. Made by Pacific Audio Supply, which is now sadly defunct.
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People used to buy used Techtronix oscilloscopes just in order to harvest the TFK 6922s inside. (Perhaps also Siemens brand.)
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While someone else mentioned that the Steelhead uses a transistor per channel as a constant current source (CCS), it is my belief that the amplification stage is actually a hybrid cascode, with a transistor serving as one half of the cascode circuit. Using a cascode, to my knowledge of tube electronics, is the only way they could be getting up to 65db of phono gain. It is also possible that the cascode is derived from single sections of two of these high transconductance dual triodes, with the transistor serving as CCS only. But since Manley do not release a schematic to anyone, this is pure speculation. What is not speculation is that you cannot get 65db of phono gain with merely a 6DJ8 type tube. I think it's a cascode driving a White cathode follower (mentioned by Evanna Manley in the 6Moons article) which drives either the attenuator, if you use it as a full preamp, or driving the external linestage. If output goes through the attenuator, then the attenuator drives yet another White cathode follower, which drives that output.
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In describing the H-6500 as a "preamp", I presume you mean either that it is a full function preamplifier with a built in phono section or that it is a linestage, with no phono section. (You must be young; in the good old days there were very few standalone phono stages, and the word "preamplifier" assumed a linestage with built in phono stage.) If the H-6500 to which you refer is a linestage (only), then from what I know of Allnic nomenclature, wouldn't it be called "L-6500"? Since Allnic do not currently market a full function preamplifier, that would seem to be the case. On their website, I do see L-6500 but not any H-6500. The H-5500 appears to be the current latest revision of the H-1201 and H-1202. I ask because somewhere else I was led into this same quandary regarding the possible existence of an H-6500 phono stage.
Although I am not an ardent admirer of tube rolling as a way of upgrading performance, I do use Siemens CCa's in my Steelhead. Do I think they made a big difference? No, but they are "nice".
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I am totally with Raul on this; spending more money, even 2X more money, is in no way a guarantee of a performance upgrade. A difference, yes, but an improvement? Not at all necessarily. Since we are all fallible and human, once we've paid a lot more money and we do hear a "difference", we are very prone to interpret that difference as an upgrade.
I like to see what's inside the chassis, and I know what to look for. In my experience, more $$$ doesn't even guarantee more expensive parts, let alone better design and implementation.
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Keep in mind that a current driven phono stage works best only with very low internal resistance LOMC cartridges. Rule of thumb is 10 ohms or less. Certain Benz LOMCs need not apply, for one example. The idea that you never have to think about loading is good marketing but specious.
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bigkidz, What is your basic upgrade? Do you have a website?
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What whart said, "...for some reason, I couldn’t get it to open up-- there was a slight electronic glaze to the sound that made it very hi-fi." The haze goes away with better coupling capacitors and getting rid of the 47 ohm resistors in the signal path. Manley uses this topology, because they have to build fool-proof units, never knowing just how many feet of cable or what impedance their product might be asked to drive. For any knowledgeable audiophile, with an intelligently put together system, the 47 ohm resistors and the 30uF of capacitance at both the phono stage and linestage outputs is simply crazy overkill.
One reason to "upgrade" is if you want to convert to balanced mode for your phono reproduction, as would be the case if you went for the Sim Audio phono stage recommended by Raul. In the one of my two systems where I use the Steelhead, it is driving Beveridge amplifiers which are single-ended all the way. So there would be not much to gain by using a balanced preamplifier. (I did think about installing transformers at the inputs of the Bev amplifiers, so they can be driven balanced.) In my other system, it is balanced all the way.
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If your Steelhead is still in warranty, I do understand your not wanting to modify it, as that would void the warranty. Fortunately for me, that was not an issue. Also, I had the needed upgrade capacitors in my stash of spare parts, so no new money needed to be spent. I did the work myself, so for zero cost, the upgrade was and is major.
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I am not about to claim that the Manley Steelhead is the best possible phono stage, but I do own one and enjoy it. I use it as a full function preamplifier to drive the amplifiers of a pair of Beveridge speakers (another topic entirely). I chose the Steelhead because reviews and comments led me to believe it was very good, and because it provides three pairs of phono inputs. I required that because I use two turntables to feed the Steelhead phono stage. FWIW, you don’t say whether you own v1.0 or v2.0 of the Steelhead. I have v2.0. The following describes the modifications I made to my Steelhead that greatly improve its Sound Quality (SQ). You will have to be someone with some electronics savvy and soldering skills:
I could not get a schematic; Manley does not provide a schematic even for professional repair shops. But if you read an interview with Evanna Manley, several years ago in 6 Moons, she describes the output stage. I won’t reiterate her summary (please google it; look for the Steelhead review in 6Moons) but suffice to say that the output of the phono stage, which either drives the volume control if you use it as a full preamplifier or the outboard linestage, if you use it as a phono stage only, uses a 47-ohm resistor in series with the signal followed by a 30uF output coupling capacitor, whichin my opinion is mediocre in quality, at best. This capacitor and what follows are holding back the performance of the Steelhead, IMO. I removed the 47-ohm resistor entirely; it’s not needed for anything, and I replaced the 30uF coupling cap with a much higher quality 10uF capacitor. (Choose whatever you like but spend the $$$ for a very good one.) You need 10uF, I calculate, because the volume control seems to have a 5K ohm input impedance (very low). (10uF driving a 5K ohm load will give you a very low bass cut-off; 30uF is way overkill. Less than 10uF might compromise extreme low bass performance.) OK, then the output from the linestage section (the output side of the attenuator) uses yet another 47 ohm resistor in series with yet another 30uF capacitor of the same type and brand. I removed that 47R resistor and replaced THAT second coupling capacitor with a 4uF film cap that I like very much. Since my amplifier has a 50K input impedance, 4uF is more than adequate to get good bass. Those two coupling capacitors, from phono stage output to attenuator and from attenuator to linestage output have everything to do with the SQ of the Steelhead. Coupling capacitors should be rated for at least 250V, to be safe.
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