| The MCML05 is the new all valve pre amplifier DIY kit,
designed by Vanderveen and manufactured by Amplimo. Two goals are met
in this design: uptime sound quality and very simple easy construction.
We made many prototypes, tested them in every technical aspect, and of
coarse they were profoundly evaluated in many listening tests. We paid
attention to the smallest details and now finally the design is approved
for production. The kit is for sale now and here we give a small introduction
to the concepts used. A profound and complete description of all schematics
is given in the Dutch language book by Menno van der Veen "High End Buizenversterkers
2", available at Segment bv. We hope that an English translation of this
book will be available soon, the German translation is already available.
The Dutch Language construction manual gives even more precise details
and literature. We now are spending much attention to the translation
of this manual to the German and English languages. Stay in close contact
with Amplimo for availability.
Above picture clearly shows the many in and outputs of this pre amplifier.
The schematics below gives more insight.

Two turntable inputs are present: for MC and MM. The special MC-10 step
up transformer is applied. You find a complete description of this transformer
on this site, section transformers. The MM pre amp uses 4 triodes per
channel with passive RIAA correction in-between. The switch S-2 on the
back side selects between MC or MM.


The schematics of the MM pre amp section is shown follwoing.
The input selector switch S-3 selects between the available inputs and
is followed by the balance and volume controls.

The selected and controlled audio signal is amplified about 5 times in
the line-stage.


At the output of the line amplifier a relays selects between main output
and headphone. This relay is activated by the headphone plug.
The power supply of the MCML05 is very special. The filament supply starts
at zero Volt and slowly increases in about 15 seconds to the final stabilized
supply voltage. The high voltage supply uses 30 seconds to get to its
final value. The start up procedure is fully automatic and prevents damage
to the precious pre amplifier valves. There is no need now for a separate
stand by switch. The supply itself fully protects and gives the best start
up procedure ever thinkable.

The next photo gives a complete overview of all sections and PCB boards.
The pre amplifier is designed for the UL40-S2 and the UL40-S2p. However,
every other good power amplifier can be used, like the PR20HE-S2 (see
the description on this site). The pictures following give two examples
how the pre and power amps can be combined.


The MCML05 DIY kit can be ordered at Amplimo (www.amplimo.com)
or at Vanderveen (this site www.mennovanderveen.nl, go to "order").
All internal audio wiring is high quality special silver wire. We think
that this pre amp needs no further modifications, but time will teach
us. Maybe Menno van der Veen finds some nice improvements, which will
immediately be published on this site.
SPECIFICATIONS MCML05 VALVE PRE
AMP
| MCML05 |
Valve pre amp |
| Design |
Menno van der Veen |
| Manufacturing |
Amplimo b.v. |
| Inputs |
4 x line;
phono: MM-MC selectable |
| Line-input |
100 kOhm; 250 mVrms nominal; 10Vrms maximal |
| MM-input |
47 kOhm; 4,7 mVrms
RIAA within 0,1 dB |
| MM-headroom |
+ 45 dB @ 20 Hz
+ 47 dB @ 1 kHz
+ 33 dB @ 20 kHz |
| MC-input |
470 Ohm (selectable)
0,47 mVrms |
| -3dB
Frequency range |
1,6 Hz to 71 kHz(min)
to 360 kHz (max);
depends on volume setting |
| Output |
3,5 kOhm; 1 Vrms nominal
11,3 Vrms max in 100
kOhm
6 Vrms max in 10 kOhm |
| Output
record |
250 mVrms nominal
or selected source level |
| Hum-Noise |
-128 dBV (C-curve) |
| Headphone |
100 mW in 30 Ohm |
| Valves |
4 x ECC82; 2 x ECC81 |
| Mains |
180-240 V @50/60 Hz
90-120 V @ 50/60 Hz |
| Power
unit |
Automatic start filament in 15 s
Automatic high voltage supply in 30 s |
| Stand-by |
Not needed for, automatic start up procedure |
| Dimensions |
30 x 30 x 9 cm |
| DIY-manual |
Very complete; 64 pages with many figures, extra
literature |
|