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[Hanzwillem]

Probably so, but I would like to know what I am building and not just put part A in spot A and so on. You cannot really find substitutions if you don't exactly know what the part does in the circuit.

[Franz G]

I will publish the complete schematics by next weekend.

For those, who order just the amps boards: dont forget to implement some 20 to 30 second switch on delay for the powerstage.

While the tube is warming up, you will get full dc output during some seconds, without implementing a delay!

Regards
Franz

[Franz G]

I am in delay with the documentation.

Reason: last weekend, I finished a PCM2706 USB DAC and played with it. And yesterday evening, I got fascinated by the idea, to build a RIAA pre with OPA2227 and designed immediately a pcb.

I hope, to finish the promised docu by beginning of the next week and offer at this time a mini-enclosure.

Franz

[Franz G]

First step: the partslist (available as Excel-sheet, see zip-file).

Mini Tube buffered GC


PSU enclosure
Amp enclosure
Chinch connectors 2
Speaker-Connections 4
230V Connector incl. Filter and switch 1
Volume Knob 1
Heathsinks 1
Tube socket noval 17.5mm dia 1
Screws etc. 1
Wires, Cables, shrink tubes 1
Torroidal 2x25V 225VA 1
Trafo 2x18V 1.5VA 2
Trafo 6V 2VA 1

PSU

PCB 1
9 pin D-sub (female) 1
Fuseholder 1
Relais 6V 1
Dioden 60V/6A MUR860 8
Dioden 100V/1A IXYS 1-16D 2
Rectifier 10V/400mA 1
NE555 1
LM317 1
LED blue 1
10000uF / 35V 2
1000uF / 35V low ESR 2
1000uF / 63V opt. 100V (low ESR) 2
470uF / 63V opt 100V (low ESR) 2
4700uF / 16V 1
47uF / 16V 1
10uF / 16V 1
1uF / 63V 3
1uF / 63V opt 100V 2
0.1uF / 63V 3
0.1uF / 63V (opt, Diode bypass) 8
200K Trimmer liegend 1
4.7K Spindeltrimmer (oben) 1
33K 2W 4
100R 2W 2
1R 0.4W 2
200R 0.4W 1% 1
3.3K 2W 1
100K 0.4W 1

Amplifier

Main PCB 1
Tube PCB 1
E88CC 1
LM3875TF 2
50K log Poti stereo 1
330uF / 35V low ESR 4
10K 2W 2
180R 0.4W 1% 2
3.3K 0.4W 2
18K 0.4W 1% 6
47K 0.4W 1% 2
0.1uF MKP 60V 4

Franz

[Franz G]

I just added an updated excel sheet, containing the parts-numbering like the psu-pcb.

The parts for the amps board are not numbered, but printed by their value on the boards.

Digi: did you draw any schematics in the meantime? We never had a schematic from the psu, we just worked with the print

Franz

[Franz G]

Here is the schematic of the amp, one channel.

Within the next days, I will post the psu schematics, a grounding scheme and the d-sub cabling.

Franz

[wim]

Are there better equivalent valves for this application? maybey the E188CC?

Is the ECC88 (no gold pins? not as good as the E88CC (gold pins) for this application?

[Hanzwillem]

That's the one I have ready for this one...

[wim]

That's a ECC88 on your photo Hanzwillem, They have no gold pins and the microphone qualitys are not that good as the E88CC (i read that from internet).

Thats why i alsked for the quality off possible substitutes.

Is the ECC88 in your opinion as good as the E88CC? If so, i use a ECC88 as well (i am a relative nooby with tubes).

[wim]

By the way Hanzwillem, nice to see that another Dutch guy is going to build this thing!