After building a few intergrated tube amplifiers, I think it is time to build a pre-amplifier now. This pre-amp is based on the Cleo 6 design of Triode Dick (Holland) and will be a great combination together with my EML 300B. This amplifier will get the same outfit as the EML 300B, so these two will be joined for life. Again a solid Curly'd Maple chassis, combined with solid Mahogany fillets, and first class (electronic) components, no compromises on this amplifier, in these times of recession:)

I won't go to much in details this time, only a short impression will be done...;

The chassis has been divided into three seperated parts, knowing a power supply part, a amplifier part, and a input/attenuator PCB part. This seperation is astablished by making cupper "walls" in the chassis, which are grounded to earth. On the photo left, a view into the attenuator room, from the rear side of the amplifier, before mounting the aluminum backpanel. Short wiring connections will be possible this way. The attenuator used in this amplifier, is the one supplied by "Tenlabs" , a re-design of the original design of Jos van Eijndhoven (Holland).

Four inputs and one output post are present on the CNC-cut backpanel, all heavy gold-plated WBT 0201 types of very good quality. They are connected to the attenuator by solid 0.8 mm silver wire.

 

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This pre-amp did cost me some serious money, but I think it's word every penny of it! There are some high cost components in ,which I think you won't easy find in commercial pre-amplifiers on the market. I tried to keep this building description short...but as always, this isn't that easy:)

A winning team is born, with the finishing of these two amplifiers, which co-operate at a very high level of transparancy. I think this is the best tube amplifier combination I have build so far! And I know it sounds unbelievable, but I run this amp combination on my Seas Super Monitors (Maple), giving me, much ,very much HiFi Joy!! Theory and practics aren't alway's in line, as I notished...

Last, but not least, a overview on the total wiring inside the amplifier...

On the photo to the left ,the 3 seperated compartments are very clearly shown.

The signal cable, is made from solid silver core, and silver plated shielded. All components are placed as compact as possible, and hard wired. Each component is isolated by teflon tube, over the solder legs. All wires are PTFE silver plated 0.6mm, heat resistant.

The amplifier is based on the design of Triode Dick, a very famous tube amp designer of Holland. For more details on this design, visit his site here.

Most of the resistors I have used are gold plated Riken Ohm 1 Watt types, and for the high power (3 Watt types) I used the Kiwame resistors.

C3 is a Black Gate Non Polar 100uF/16V type, for C4 I have used a Auricap 3u3/400V Cap, and for C1 I used a MKP 0.47uF/400V Jantzen Audio cap.

 

The coupling caps C5 are represented by 0.47uF/630Vdc Obligato Premium Audio Caps.

 

Of coarse potentiometer P1 is replaced by the high performance uP controlled attenuator from Tentlabs.

The black sleeve on the photo contains the attenuator control wires, coming from the display/encoder PCB on the front panel, and goes to the attenuator main PCB at the rear.

 

 

All metall brackets, used for the yellow caps and the cupper panels are self made to offer best fit.

Below a picture of the power supply compartment, with the Black Gate cap's, the relais, main transformers, and chokes. The power supply is totally (seperated) double Mono build, as can be seen on the photo.

The 2 tube sockets are for the 6X4 rectifier tubes, close to the chokes. All AC wiring is seperated by the cupper panels of 2mm thick solid cupper. The DC regulated voltage B++ is fed through rubber tules.

Main power is switched by a small 12Vdc relais, fed by a small 12V transformer, with a regulator circuit on it ,to convert the voltage to DC. The relais is activated by the chrome plated button on the front.

All mounting holes on the top plate (chassis) are "blind" holes. This leaves no screw heads visible on the top plate. By inserting m3 studs, I make it possible to mount e.g. the tube sockets, and fix them with a m3 nut, see picture on the left.

Both main transformers, and also the 4 chokes are mounted on rubber feed to eliminate vibrations to the chassis. All screws are locked by "Loctite" flued, to prevent nuts from loosing.

The line stage is build up around the Russian 6N30p tube and the German (Telefunken) D3a tube. A great combination, as I have noticed! No noise, no hum, nothing at all...It gives you pleasure to listen to. The 6N30p will be glowed by a nice Tentlabs heater supply module, to establish a clean 6,3V heater voltage. Notice that the 6N30p needs some 900mA heater current, a bit more in comparison to the D3a which needs only some 300mA.

The transformer set used here, is a AE-Europe set, consisting of 2 main transformers, and four amorfe-core chokes. The power supply will be build-up totaly seperated on both channels. I had the opportunity to buy some of the last Black Gate power supply capacitors, as they are no longer available now:(  I think these are the best caps to use on this place!

The bronze colored frontpanel, makes a very nice combination together with the Maple/Mahogany...

I have used my self-designed solid aluminum knob-UX4 ring combination here, (which I have a few for sale too) this gives a very professional look I think.

All aluminum anodised chassis plates are self designed using the Schaeffer designing programm. Knowing the bottom panel, front panel, back panel, and top plate.

The attenuator control PCB is mounted on a self-designed front panel (picture below), having a digital read-out of the volume, and input stage. The volume/input selecting knob is placed on a series of blue Led's to create a nice blue back lighted knob, see photo below.