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Wednesday, September 11, 2019

The D3a Preamplifier


Since many customers mind the size of the 4 chassis preamplifier combo of the 10Y line and D3a phono stages, I decided to introduce a new 2 chassis full function preamplifier. The D3a preamp.

Although there is a full function preamplifier in my line up, already the Octal preamp, it does not use a LCR EQ phono stage. But I often get inquiries for a full function preamp with phono stage on board, which utilises LCR EQ. So here it is:

Power supply on the left and signal unit on the right. For the demo units I chose different color schemes. Of course both can be had in the usual color schemes I offer.

The signal unit uses all D3a tubes and the phono section utilises my new SplitPath EQ approach. Thus it offers an extremely short signal path. Frequencies above 1kHz traverse only through 2 of the 3 tube stages. And that includes the line section which of course uses transformer volume control and offers high maximum output voltage at very low output impedance.

The integration of the phono with the line stage enabled the elimination of a pair of signal transformers from the signal path so this preamp is extremely transparent sounding, especially strong with voices and minute details otherwise lost in the background. Noise floor is even lower compared to the already very quiet 10Y/D3a combo.

In order to fit everything side I had to lengthen the chassis from the usual 40cm of the portrait style units to 46cm. All other dimensions are the same with 27cm width and 12cm height of the wooden body, plus 2cm for feet and 11cm for the transformer covers (13cm on the power supply chassis) for a total height of 25cm (27cm power supply).

Here some photos of the construction process of the prototype, starting with the top plate.

The phono section uses the same arrangement as the stand alone SplitPath EQ phono, with another pair of D3a tubes added at the front.

More components to be mounted on a separate support plate:

The 600 Ohm LCR RIAA EQ, separated for the bass turnover and treble roll off sections:

The completed signal unit, it is quite crammed inside.

The prototype has 3 line inputs in addition to the phono input. The phono input can be configured for different classes of MC cartridges: low output, medium output and high output. All line inputs can be RCA, XLR or both. XLR and RCA outputs are available.

I am extremely happy with this new unit, which offers the shortest signal path of all my phono solutions, with the associated gain in sound quality. While many may prefer the slight euphonies of the 10Y line stage range, this preamp is a statement in neutrality. And I have not tried an all silver version of this yet.

Drop me an email if you are interested or want more information. I am now taking orders for this preamp.

Best regards


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