Mini-Me phono preamp

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#41
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#46
Hello Herman,

i have compared the Mini-Me with several phono stages like,

- phonodude PhonoDude deel 1
- project tube box SE. Pro-Ject Audio Systems
- and several opamp stages.

I like the Mini-Me best, but this is my own subjective opinion.
I shall try to describe the differences.
The opamp stages have a detailed, good defined sound with not so wide soundstage.
The project tube box sounds like the opampstages with less detail.
The Mini-Me sounds like the Phonodude a much wider soundstage, with more live in it, i like to listen to it. Just the sound i expect from a tube stage.

Further no noticable humm or noise.

About the PCB i have no intention to produce them. But it is very easy to make them yourself.

Cheap and Easy Toner Transfer for PCB Making

Ronny
 
#48
There will coming a Mini-Me second edition soon.
I am developing it right now.
It is cheaper and easier to build with only one 48v power supply. Using the 6n28b-v miniature tube. Board size only 100x100mm.
 

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#52
Koifarm said:
Today i build one MC stage for testing purpose.
I discovered a fault in the PCB at the MC pre input, i shall correct that a.s.a.p.

...

I did not use the Zener in the MC pre because there was no humm at all. I shall modify the schematic a.s.a.p.. For the heatersupply i used an extra LM7806.

I am very pleased🙂
Click to expand...

Hi koifarm,
sorry for posting this so late in the thread.
You mention an additional LM7806 for the heatersupply
which is not included in your schematics.

Is that needed for the MC stage?

regards
 
#53
Hello Sebuschi,

i am still supporting this thread and use this preamp in my phono setup.
The 7806 is not needed. V5 en V6 of the mc pre have the heaters in serie on the 12v supply with is stabelized with the 7812.

I used the 7806 only to test one channel of the mc pre. I neede just 6v for one heater.

Ronny
 
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#54
Koifarm said:
Hello Sebuschi,

i am still supporting this thread and use this preamp in my phono setup.
The 7806 is not needed. V5 en V6 of the mc pre have the heaters in serie on the 12v supply with is stabelized with the 7812.

I used the 7806 only to test one channel of the mc pre. I neede just 6v for one heater.

Ronny
Click to expand...

Hi Ronny,

many thanks!
I have one more question: Do you have a list of the condensers (more specific than 220µF/250 V) with the types or even the brands of the condensers?

Regards
Achim
 
#59
Koifarm said:
It is possible that i interprate the measurements wrong. In reply 11 and 12 i ask how to read the graph. No one anwser.
Click to expand...
What was your output signal voltage level?
Your software probably uses averaging to reduce the noise floor, which will make the results seem quieter than they really are.

Incidentally, your choice of MC input stage is quite noisy. You can improve the SNR by perhaps 4dB by connecting the two triodes in parallel and using a simple anode load resistor, instead of stacking the two triodes.
 
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