Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on March 11, 2013, 05:21:00 am

Title: A proposal for Doug and the Forum
Post by: kagliostro on March 11, 2013, 05:21:00 am
Why, here in the forum, we don't develop a pair of FXLoop and a Relay unit  like this ?

(relay unit will be an improvement on the existing Doug relay unit that maintains the utility of the standard Doug's relay board for many uses, not a substitution for the existing one)

This unit uses a very small 6112 double triode tube

https://www.tube-town.net/ttstore/product_info.php/language/en/info/p5992_Kit-Tube-FX-Loop-6112.html (https://www.tube-town.net/ttstore/product_info.php/language/en/info/p5992_Kit-Tube-FX-Loop-6112.html)

https://www.tube-town.net/info/datenblaetter/kits/tt-fxloop6112.pdf (https://www.tube-town.net/info/datenblaetter/kits/tt-fxloop6112.pdf)

This unit uses the small LND150 Mosfet

http://www.tube-town.net/ttstore/product_info.php/info/p5973_Kit-Serieller-FX-Loop-LND150.html (http://www.tube-town.net/ttstore/product_info.php/info/p5973_Kit-Serieller-FX-Loop-LND150.html)

https://www.tube-town.net/info/datenblaetter/kits/tt-fxlooplnd150.pdf (https://www.tube-town.net/info/datenblaetter/kits/tt-fxlooplnd150.pdf)

This relays unit incorporates jack intake

http://www.tube-town.net/ttstore/product_info.php/info/p5910_Kit-Doppel-Relais-Umschalter--6-V.html (http://www.tube-town.net/ttstore/product_info.php/info/p5910_Kit-Doppel-Relais-Umschalter--6-V.html)

http://www.tube-town.net/info/datenblaetter/kits/kit-chsw2-6.pdf (http://www.tube-town.net/info/datenblaetter/kits/kit-chsw2-6.pdf)

I don't say to copy the circuits as thy are, I say we can draw/develop our version

and when finish, If Doug is interested, he can put the PCB on his catalog

K
Title: Re: A proposal for Doug and the Forum
Post by: moonbird on March 19, 2013, 03:21:27 pm
Sounds like a good plan to me. I would like to see more use of sub-mini tubes. Seems they would be a very size-efficient way to add features to existing amps. I would like to add a sub-mini-based reverb and/or tremelo board(s) to k's list as well. There is an excellent and comparatively low cost supplier of *many* different sub-mini tubes on the bay these days. Not sure if I can give his name tho.
Title: Re: A proposal for Doug and the Forum
Post by: moonbird on March 19, 2013, 05:08:12 pm
Subminis might also be a good way to add controllable OD circuitry into traditional tube amp designs WITHOUT injecting those "nasty" SS parts - just a thought!!  :dontknow:
Title: Re: A proposal for Doug and the Forum
Post by: sdp1234 on March 22, 2013, 08:53:13 pm
I'd love to build a submini effects loop... problem is that to date none of my amps have had effects loops and I haven't worked with submini's.  I'm getting ready to build a couple October studio type amps (from the AX84 site) .  Wanted to try the effects loop but I'm not sure there is enough room.  A submini or mosfet effects loop may be easier to fit.  Tried looking around but haven't found much information.
Title: Re: A proposal for Doug and the Forum
Post by: DummyLoad on March 23, 2013, 04:07:12 am
sub-miniatures cool and all BUT, problem is there are no new production tubes and sockets are very scarce. you can rig to work an 8 pin DIP IC socket but that is sub-optimal or, you solder direct to a PCB (shudder!). there are some soviet military NOS sub-mini's floating around on ebay that claim to be 6111 and 6112 subs. so, what then when those dry up? just some things to think about...

respectfully, 

--pete 
Title: Re: A proposal for Doug and the Forum
Post by: kagliostro on March 23, 2013, 08:38:20 am
Some time ago I've find this schematic that is claimed to be a good High Voltage SS FXLoop circuit

(http://s8.imagestime.com/out.php/i778466_LND150preamploop.GIF)

---

About 6112 tube, Pete is right, but may be we can find an adequate 7 pin tube for that purpose

and the montage do in horizontal this way


K
Title: Re: A proposal for Doug and the Forum
Post by: sdp1234 on March 23, 2013, 01:58:15 pm
Im pretty slow but i think ill try to pot this together on a small turret board.
Title: Re: A proposal for Doug and the Forum
Post by: sdp1234 on March 24, 2013, 11:54:42 am
In the ss fx that is shown,  what is the purpose of the switches and pre out? 
Title: Re: A proposal for Doug and the Forum
Post by: kagliostro on March 25, 2013, 05:35:14 pm
The pre out is what it is

an exit to an external Power Amp

---

The switch select the desired level of signal

K
Title: Re: A proposal for Doug and the Forum
Post by: sdp1234 on March 26, 2013, 07:56:45 am
I've been looking for schematics and descriptions of ss effects loops in a effort to learn and prepare to build and test one.  There is one listed about half way down this thread that looks a bit simpler for starters.  Thoughts?

http://ax84.com/bbs/index.php?area=-1 (http://ax84.com/bbs/index.php?area=-1)
Title: Re: A proposal for Doug and the Forum
Post by: sluckey on March 26, 2013, 08:39:11 am
Could you be more specific?
Title: Re: A proposal for Doug and the Forum
Post by: sdp1234 on March 26, 2013, 02:54:05 pm
Sorry Sluckey,

I've been pretty swamped with non amp stuff.  I'm interested in a bunch of stuff but due to my lack of time I've become lazy with my posts.  I'll give this basic loop a try and follow-up with reasonable questions based on the results.



Thanks

Title: Re: A proposal for Doug and the Forum
Post by: mrsmash23 on July 07, 2014, 03:09:34 pm
Hello everybody!

SDP1234: Can you confirm that mosfet fx loop you posted is working?

Or did anyone else try it? Optimal B+? Is there different fx loop circuit that has been verified?
Thank you in advance! Hope this post is not dead! :worthy1:
Title: Re: A proposal for Doug and the Forum
Post by: sdp1234 on July 11, 2014, 09:43:21 am
I haven't done anything amp related (other than a few repairs for friends) in quite a while.  I have a long list to get started on but work and life in general has kept me more than busy.  Sorry