Germanium phono . Who uses phonopreamp on germanium transistors ?

[Andr039]

Черт, Виктор, выглядит в лучших традициях советского лабораторного оборудования!
Мои поздравления!

[vs music]

Черт, Виктор, выглядит в лучших традициях советского лабораторного оборудования!
Мои поздравления!

Спасибо , Андрей !

[vs music]

Hi ! Another phonopreamp . Sergey Toropov 's original circuit was based on 5 transistors ( 2 FET + 3 germanium ) .
 But I want to add transistors to the first 2 stages .
There must be something like this. As a FET, I want to apply assemblies K504NT-3/4 ( manufactured in the USSR ) .
But the experiment has just begun . To be continued....

[mamakasou]

Victor, you build and post amazing stuff.
Right now, I think you deserve the title of the most serious (and prolific) germanium guru and aficionado.

It inspired me to start learning PCB etching from schematics, so In the end I can build a germanium phono of yours.
And possibly a headphone amplifier too.

But, still not there yet.
Tried toner transfer on blank copper PCB with mediocre success.
Then I used pre-sensitised PCBs (from Bungard). Again, with not very consistent results.
The film is very thin and you risk the danger of wiping it off when exposing it. Gives evry small margin to actually dissolve the cured areas.

Anyway, I hope I'll get more consistent results with the photosensitive plastic film.
Preliminary results have been encouraging, although the exposure is still tricky.

So may I ask you what is your recipe?
How do you 'bake' your own PCB?

[vs music]

...

[vs music]

Victor, you build and post amazing stuff.
Right now, I think you deserve the title of the most serious (and prolific) germanium guru and aficionado.

It inspired me to start learning PCB etching from schematics, so In the end I can build a germanium phono of yours.
And possibly a headphone amplifier too.

But, still not there yet.
Tried toner transfer on blank copper PCB with mediocre success.
Then I used pre-sensitised PCBs (from Bungard). Again, with not very consistent results.
The film is very thin and you risk the danger of wiping it off when exposing it. Gives evry small margin to actually dissolve the cured areas.

Anyway, I hope I'll get more consistent results with the photosensitive plastic film.
Preliminary results have been encouraging, although the exposure is still tricky.

So may I ask you what is your recipe?
How do you 'bake' your own PCB?

Hello!
Thank you for evaluating my work .
 But - my recipe is not simple . I draw my printed circuit boards by hand .
About 15-20 years ago I tried to print a drawing of the board using a laser printer ( in a mirror image ) . I used glossy paper , similar in properties to the paper in advertising booklets . Then I used a hot iron to transfer the drawing from the paper to the board . Then etching .
The result was not always good .
 As a result , I draw the boards manually . I do not need replication - all this is made in one ( or sometimes in 2-3 copies for friends ) .

[niclaspa]

I have been making PCBs since I was 12.  I use circuit board laminate with photo resist.  You need to create the connections on a transparent or semi-transparent film.  When I was a kid, this was done with curve tape and transfer symbols.  These days, it is best done with a CAD program.  I use KiCad and it is for free.  Print your design out on a transparent film.  If you use a laser printer, make sure that the film doesn't become deformed when exposed to heat.  After that, put the film on the laminate and expose to a UV lamp.  The time needed depends on how strong your lamp is.  Then develop the circuit board in water with a bit of sodium hydroxide.  Finally, etch it in sodium persulfate. 

I have not tried this, but I believe that, these days, you can send your CAD drawing and get the PCB manufactured for not a lot of money.

An alternative approach is to build the circuit on solder tags, like I did when I built a germanium phono stage: https://www.lencoheaven.net/forum/index.php?topic=36187.msg480696#msg480696

[CJG in Wolfsburg]

I’ve just ordered this for my office setup:

https://ebay.us/m/MlnYp0

Looks interesting: it’s based on a Telefunken TV206 with an extra buffer stage and modern capacitors. Power is from a 5V power bank via a filter and DC/DC converter.

It will go between the NOS Shure M44G on my Dual 1019 and a line input on the Braun CSV300 (which has a very ordinary phono input: two amplification stages and plenty of electrolytics in the signal path).

Should be interesting…

[CJG in Wolfsburg]

Here it is:

[stratokaster83]

Very nice of Mr. Otto to include the circuit diagram. Looks like a typical 2-transistor phono stage, these usually have relatively high distortion because their open-loop gain is limited, but it should be mostly even-order harmonics. The simple emitter follower at the output should add some sweet 2nd harmonic as well. Overall it probably has a very “vintage” sound, especially with germanium transistors.

[CJG in Wolfsburg]

Frankly, it sounds “tubier” than my tube phono stages…. A nice transparent midrange but limited extension at the frequency extremes. Due to the battery power supply it is also very quiet.

Much better than the Braun’s onboard phono stage, which has numerous electrolytic caps in the signal path, and insufficient space to substitute decent quality components.

[vs music]

Here it is:

Congratulations on your successful purchase!