FX-Loop add-on for guitar amps

DarkRain · Post by **DarkRain** » 27 Jul 2014, 07:08

This is a new project.
An FX-Loop add-on that can be used on any guitar amp that doesn't have one. Plug and play, standard 6.3V heaters / From Pre / To Power and B+ pads.

It's using a 6N17B submini triode.

Best regards,
Gabriel Tudoran

sinner · Post by **sinner** » 27 Jul 2014, 15:51

Submini? That's a cool idea!

lead2203 · Post by **lead2203** » 28 Jul 2014, 02:45

sinner wrote:Submini? That's a cool idea!

http://www.tube-town.net/ttstore/Kits/M ... :5992.html

DarkRain · Post by **DarkRain** » 28 Jul 2014, 04:37

@lead2203: excellent

but i don't see the similarities ... except the use of a subminitube... and as far as i remember, the schematic is not available.

Best regards,
Gabriel Tudoran

DarkRain · Post by **DarkRain** » 28 Jul 2014, 06:33

Sorry for the double post, but, here is the schematic

Best regards,
Gabriel Tudoran

lead2203 · Post by **lead2203** » 28 Jul 2014, 06:49

DarkRain wrote:@lead2203: excellent but i don't see the similarities ... except the use of a subminitube... and as far as i remember, the schematic is not available.

Best regards,
Gabriel Tudoran

Its just a regular loop like this one.

DarkRain · Post by **DarkRain** » 28 Jul 2014, 07:15

Indeed it's a regular loop... i didn't even say it was anything else or something very complicated. I have approx. 300pcs of 6N17B and want to find a use for them so among other things this is one.

And maybe someone is interested in building it, i made them to be sold but, that is why i've posted the schematic here , and when the PCB will be ready i will also post it here...

Do you see any problem in this way of making things?

Best regards,
Gabriel Tudoran

Serge75 · Post by **Serge75** » 07 Oct 2014, 16:53

Hallo, it s very interesting, do you think this loop could be implemented in an Epiphone Valve Jr? Thank you!

tonyharker · Post by **tonyharker** » 07 Oct 2014, 18:03

So can you tell us please, what B+ are you using?

DarkRain · Post by **DarkRain** » 07 Oct 2014, 18:13

@Serge75: yes it can be used without any problems if there is enough space inside the amp.

@tonyharker: it can be used with any anode voltage as long as you use a drop-down resistor (the anode current it's aprox. 3mA so a 2w resistor should be more then enough).

Here you have the brochure of the module (this is V2 with a local RC filtering).

Best regards.

Serge75 · Post by **Serge75** » 08 Oct 2014, 09:53

Thanks for the reply, DarkRain, my amp is like that, more or less, mine has some more modifications, my question is where exactly would be the insert points for the send and return? And by the way, send me a message, in case you dont want to publish here, for the price including shipping, I m in Spain.
Thank you!
Cheers

DarkRain · Post by **DarkRain** » 08 Oct 2014, 10:15

@Serge75: Thank you for your question. You have a PM.

Regards.

tictac · Post by **tictac** » 08 Oct 2014, 20:07

You need R1 or the gainstage won't work. If you think it's loading the circuit down you can increase it to 1 or 2M

TT

DarkRain · Post by **DarkRain** » 09 Oct 2014, 07:58

That is correct Serge. The grid would float without the resistor. I would not go with anything bigger then 1.5M or smaller then 500k.

Best regards.

Serge75 · Post by **Serge75** » 20 Oct 2014, 13:02

That is the actual schematic, I had made some mods to it, and the other schematic had few things in common with the amp.D This last one is more accurate.

DarkRain · Post by **DarkRain** » 21 Oct 2014, 08:22

Hello Serge,

This is the way you should hookup the FX-Loop Module:

Also you will need to drill 2 holes / 4cm apart and with a diameter of 11-11.2 mm

Regards,
Gabriel

J0K3RX · Post by **J0K3RX** » 22 Oct 2014, 07:00

Hey Gabriel this is the typical classy stuff from you!!

I had and idea when I saw your layout since your 100k pot was so strategically placed directly behind the Send...

Have a look.... you could even make it LED backlit

DarkRain · Post by **DarkRain** » 22 Oct 2014, 07:08

Hhahahaha! Great minds think alike. That was the original idea behind this, but i didn't have any vertical mount trimpots

) and i used the horizontal ones, that is why i didn't cut the cap of the jack

I can't believe that

) nice one

Regards.

J0K3RX wrote:Hey Gabriel this is the typical classy stuff from you!!

I had and idea when I saw your layout since your 100k pot was so strategically placed directly behind the Send...

Have a look.... you could even make it LED backlit

Serge75 · Post by **Serge75** » 24 Oct 2014, 08:12

Thanks for the drawing, Gabriel, so as you were saying this could be modded to have the return level controlled as well, but do you find it necessary? The other big blue resistor next to the return jack is the one that should be substituted for a trimmer? And more trimmers in place of original resistos wouldnt mean an increase in noise? When I ll receive it I ll try it.
Cheers
Sergio

DarkRain · Post by **DarkRain** » 24 Oct 2014, 08:56

Hello Serge,

I didn't say that you can mode it to have a return level - you have a send level already

- And no it's not necessarily at all, as in your case the RETURN level is practically the volume pot.
The big resistor is the 100k anode resistor! Do NOT use a trimmer there

A RETURN level trimmer in you case(and in everybody's case per-se it would be futile and without any purpose.

Best regards,
Gabriel

PS: Your package should be ready for shipping tomorrow morning.

Serge75 wrote:Thanks for the drawing, Gabriel, so as you were saying this could be modded to have the return level controlled as well, but do you find it necessary? The other big blue resistor next to the return jack is the one that should be substituted for a trimmer? And more trimmers in place of original resistos wouldnt mean an increase in noise? When I ll receive it I ll try it.
Cheers
Sergio