Feeler: Classic Solo

[Walrus]

Have you linked J4 to J5 on the bottom of the pcb, as there isn’t a link on the top?

 

[TillM]

Hi Kevin,
no I don’t.
Do it after reading your post and now it works.
Good damn.
I thinked about, but also thought, they are just for DI-Use.
Thank you very much !

 

[ruffrecords]

Hi Kevin,
no I don’t.
Do it after reading your post and now it works.
Good damn.
I thinked about, but also thought, they are just for DI-Use.
Thank you very much !

They are for DI use but if you don't have a DI you need to link them. I am pleased you got it working. My friend Pierre hosts an independent gallery projects that people have completed based on my designs:

https://theworldin35mm.com/projectgallery/

If you have any when your build is complete you can send them to me if you wish and I will pass them on to Pierre.

Cheers

Ian

 

[TillM]

Hi Ian,
I want to use a DI, but I linked the DI to the toogle board to the line molex.
So I hope, I did not something wrong.

Till

 

[ruffrecords]

Hi Ian,
I want to use a DI, but I linked the DI to the toogle board to the line molex.
So I hope, I did not something wrong.

Till

The input impedance of the line input is about 7K. This is probably too low for guitars. Normally a DI input wold be fed straight  into J4.

Have you read the documentation about how to set it up for various uses? You can find it on the DIY tab of my web site:

https://www.customtubeconsoles.com/diy

Scroll down and click on the Classic Solo folder where you should find all the info you need.

Cheers

Ian

 

[TillM]

Yes I read it, but I thought, i can connect the line to my di input jack.
Will try it later, if not, I will connect J4 to my DI input jack.
But for now the preamp work fine and sound great.
Thanks so much for your help !

 

[TillM]

Finally I’m done!
I learned a lot with this preamp.
Now I’ve a wonderful sounding unit and with the output gain I can drive the tubes harder.
Ian thanks so much for this project !
I am already in love !

 

[ruffrecords]

Nice pic. OK if I send it to Pierre? Do you have a shot of the inside?
Is that a Galaxy enclosure?

Cheers

Ian

 

[TillM]

Yes of course!
But I'll send you better pics tomorrow to your mail-address.

Yes it's a Modushop Galaxy enclosure.
The front- and back panel was drilled and printed by Frank.
I used AVD transformer in and Edcor out.
Capi T-Pad for output attentuation and Phillips 6922 JAN tubes.
The rest is standard.

My Mic/Line switch is now a mute switch, cause I first thought, I can use the line switch for my DI.
So I've just one xlr input.
I think about using the same input for the line switch, then I can drop the input gain about -30db.

 

[mgb54]

I'll start to put a pair of these together soon! Has anyone experimented with adding an LED to show when phantom is active?

 

[TillM]

I'll start to put a pair of these together soon! Has anyone experimented with adding an LED to show when phantom is active?

No experience, but you can use it like in the ez1290 build.
Just connect the plus of the LED to pin 2 and 3 and the minus pin to audio ground.
I would use a something between 5k and 10k as LED resistor connect between XLR pins and the plus pin of the led.
But maybe Ian can chime in and prove me wrong.

 

[ruffrecords]

I'll start to put a pair of these together soon! Has anyone experimented with adding an LED to show when phantom is active?

Depends what you mean by  active. The usual method is just to connect the LED via a suitable series resistor (10K should work for many LEDs) to the switch that turns on the phantom power so when phantom is  turned on the LED comes on too. I do not recall the total current the Classic Solo power supply can provide  from the phantom supply but I do not expect an extra 5mA would worry it too much.

Cheers

Ian

 

[mgb54]

Thanks Ian and TillM, I'll report back when built!
Cheers

 

[mgb54]

Depends what you mean by active. The usual method is just to connect the LED via a suitable series resistor (10K should work for many LEDs) to the switch that turns on the phantom power so when phantom is turned on the LED comes on too. I do not recall the total current the Classic Solo power supply can provide from the phantom supply but I do not expect an extra 5mA would worry it too much.

Cheers

Ian

Hi Ian, this indeed worked a treat, low-current LED with 10k in series to the switch. Thanks.
The preamps are complete and sound fantastic! In the Galaxy GX388 enclosure, 2 boards both powered by the Don Audio Mila toroidal, Cinemag input transformers, Edcor output transformers. Very satisfying project. Current front panel is......charming/ropey...... Just needs some better knobs and a power switch now (and maybe a prettier front panel....).

Cheers

 

[ruffrecords]

Excellent. It is good to see another couple of these going into service. If you have any pics you feel able to send me I will pass them on to my friend Pierre who runs an independent gallery of pics of completed projects based on my designs. And it you are ever able to send me some samples of them in use that would also be great. I get so many many requests like "do you have any samples of the sound of these preamps"

Cheers

Ian

 

[TillM]

I've a weird problem since I install a led for phantom power.
I use a low current led and connect it with a 10k resistor to the toggle and - to ground.
The led turns on, but it's to light is nearly not to see.
The biggest issue is, that I get -61vdc at pin 2 from XLR.
When I disconnect the led, I get not voltage from phantom, only when I install the led I get vdc at the 48v pin,
But a I said, when I measure vdc I get -61v.

Before I install the led I had stable 48,2vdc.
What could be the mistake, before I change everything at the phantom section.

 

[ruffrecords]

Are you using the 4 toggles PCB for switching phantom or have you wired it some other way? You cannot use the switch on the 4toggles PCB to switch an LED.

First you should try to disconnect the phantom at the Classic Solo PCB and then check if the phantom voltage is correct on that PCB.

Cheers

Ian

 

[ruffrecords]

OK you cannot use the switch on the 4 toggles PCB to switch an LED. If you dio this will explain why you get a funny voltage on pin 2 of the XLR.

Cheers

Ian

 

[TillM]

So, when I disconnect the 48v cable from the toggle board I get -0,04vdc at the 48v pin.

 

[ruffrecords]

So, when I disconnect the 48v cable from the toggle board I get -0,04vdc at the 48v pin.

OK, and at that time what is the voltage at the 48V pad on the Classic Solo PCB?

Cheers

Ian