Grade, hereafter referred to as C 1 before our true features machine,
We should indicate that up days grade is not beyond the scope of the following several circuits
before popular valve pre amp in the world first.

Tabulate it as follows separately now:
Circuit type
Advantage Shortcoming

Marance 7 type

This circuit is classics the most, emerged in the fifties.


The circuit is simple, middle pitch is energetic, especially the male voice loud and clear , the news is dry than the height. Without trends, heavy BASS is insufficient, high frequency spreads the difficulty, have not analysed strength . Strengthen degree and is defeated by feedback inhibition noise. The amount of information has enormous loss when low impedance is exported.

( 2) With field being getting luxuriant Circuit this whether Japan and field luxuriant one improve to Marance 7 shortcoming of type on the sixties.


Seem to solve the shortcoming of type 7 all horses. Circuit this comparatively complicated, very easy to is it hold tube quality of component influence to hinder each, because enlarge great, so dry than strengthen NFB raise the index also to news, general DIY friend have few outstanding and successful writings .

 ( 3) SRPP

Pull/push  upper and lower PL forms by two triodes, every famous-brand par edition of America and Europe go to use it more.


Lack high-frequency and lucidly and elegantly and distortedly, female voice delicate and beautiful, make overtone to be sufficient as NFB. There is no BASS of the weight sense , the trends are insufficient, analyse about the great music which piles the head that strength is insufficient! Sensitive to the tube, it is loud to change the sound difference after the tube. Pay attention to what America and Europe famous-brand tube does it pursue , change domestic to transfer school bias voltage resistance might be also in charge of the ocean by several times carefully after in charge offing. Generally all in output and connecting a triode do the negative pole and output the purpose on this circuit. Increase and export the electric current, DIY is apt to succeed, but the whole sound is not enough for the atmosphere !

Our C 1:
Circuit characteristic:
Not needing the negative feedback, there is not phase place to cut apart, the independent transformer of each sound channel, valve rectification, valve steady voltage,  valve servo , the part of the audio frequency liner amp uses four triodes, the electronic switch type filament is encouraged! The complete machine has used ten tubes .
Advantage :
Collect all strong point of the vacuum tube in an organic whole, the ones that have possessed the electric crystal machine even more are powerful and quiet ¡­¡­
Shortcoming: The circuit is complicated, make and expect much, the specification market of the component is difficult to research , we plan to put out the market at the price restraining oneself most .
One has no speech of avoiding                          
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