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Thursday, December 10, 2015

The Ultimate Line Preamplifier, Part 2


The all silver differential line preamplifier which I announced in October, has been finished since a while. I finally found the time to take some photos and test it.

The unit got finished in a dark wood (smoked eucalyptus) with graphite grey metallic transformer covers.

As with all 10Y line stages the power supply is completely separate:

It houses separate choke filtered filament supplies for both channels and a choke filtered B+ supply using the well proven full wave bridge arrangement with 4 6AX4 TV Damper tubes.

The signal section is completely free of any capacitors.

There are 4 filament chokes under the transformer covers. Inside the chassis there are 14 (!) silver transformers and chokes.

Silver volume control AVCs, silver line output transformers, separate silver wound plate chokes for each tube and a separate pair of silver input transformers for each of the 3 inputs.

This line stage is equipped with a quad of 1602 tubes, a special low microphonic variant of the 10Y.

The big question now, was it worth the effort and expense?

Short answer: Yes absolutely!

When I was challenged with the task to build a line stage which out classes the silver 10Y line stage, I was skeptical if any significant advance in sound quality could be achieved. After all I am very happy with the base copper version of it and happily use one every day. The silver version puts some icing on the cake of that. What more could you wish?

I am normally hesitant to write about the sound of my creations. I have written a lot about the subjectivity of such sound descriptions and of course I am biased. Still I understand that you want some sound impressions.

This new preamp took me by surprise. I first listened to it with some regular 10Y tubes, not even carefully matched ones. I was shocked by the sheer realism which I heard. This preamp sounds incredibly warm. By that I don't mean a 'tubey' warm sound, but a very realistic and natural reproduction.

Today I plugged in a matched quad of the fabulous 1602 and got blown away. Each tone seems to be more textured than before. Each little detail is plainly audible. Yet the representation does not fall into pieces what can often happen with systems which try to be analytical. But everything stays integrated and is easy to listen to without any fatigue. New details pop up on well know records.

The single ended line stage is not really a slouch in terms of realism and resolution, it actually really excels in that and I was surprised to realise that even more is possible. All that combined with the incredible warmth. Normally I am not much into sound staging but I also noticed a added realism in that regard. Again a property in which the standard line stage is already extremely good. Especially with atmospheric electronic music this preamp seems to paint the tones into the room. Also the bass representation is wonderful. Each bass note is more present than before with all the detailing of the textures of the sounds.

The conversion from copper to silver has brought more improvement in the differential line stage than it did in the single ended version.

So this preamp deserves the title of my ultimate line preamplifier.

Please forgive the long rant which is not usually my style. But this preamp deserved it.

Of course this new preamp won't make the standard version obsolete. It comes at considerable cost after all.

As I have written before: The secret to achieving good sound is to be happy with what you can afford or simply to enjoy what you have.

But if budget is not an issue, I can only recommend to consider such a preamplifier. I am trying to imagine how it would sound in combination with a fully differential and all silver phono preamplifier, which I still have to build.

I will be able to enjoy this preamp for a little while before it will be shipped to it's new owner.

Best regards



  1. This is just stunning. Something I could only dream about. I will try to take your advice and be happy with what I can afford (but to do that I have to stop reading your blog..!)

  2. Hi Thomas, what are this circular power connectors ?

    1. The PSU connectors are am phenol military spec connectors. The others are XLR