Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: BrainDeadAmps on January 16, 2023, 01:34:13 pm

Title: fx loop worth implementing?
Post by: BrainDeadAmps on January 16, 2023, 01:34:13 pm
So, I've been working on this scratch build for the past week and finally got the reverb sounding how I wanted. I originally planed on building some sort of single ended reverb amp where I could have an "fx loop" between the pre-amp and the power section so I could place a dummy load on the amp and run the reverb preamp in front of other amps that don't have reverb. I've attached below the amp in it's current state. Would the heavy load of the t/s and vol. pot render the fx loop rather useless?
Title: Re: fx loop worth implementing?
Post by: Williamblake on January 16, 2023, 03:01:17 pm
Your schematic looks like a pedal friendly fx circuit. If it works, only you can tell. My humble expierience on reverb loops is to put them where you could split your circuit into independend units anyway, and you already did that. But from your description it sounds like you don't need the speaker output? Is that the hassle?
Title: Re: fx loop worth implementing?
Post by: Williamblake on January 16, 2023, 03:05:18 pm
Meaning: Maybe the job is well done and anything after fx-send can be omitted? Maybe another cf?
Title: Re: fx loop worth implementing?
Post by: BrainDeadAmps on January 16, 2023, 03:21:56 pm
But from your description it sounds like you don't need the speaker output? Is that the hassle?

No, I guess I was hesitant due to the 500k pot before the fx send. When I set out to build this, I originally had the reverb inserted in the circuit similar to how I've seen in many of bassman-topology/tubenit's reverb amps posted on the forum. The volume pot at the end of the t/s is usually omitted to accommodate the fx send. I could get a nice mellow reverb with that circuit design, but I was really wanting to get an extreme surf settings. I moved the reverb to v1 which gave me the reverb control I was looking for.
Title: Re: fx loop worth implementing?
Post by: tubenit on January 17, 2023, 05:37:07 am
This is how I did my "active" FX loop on my Minimalist. I am very happy with how it works.


With respect, Tubenit
Title: Re: fx loop worth implementing?
Post by: BrainDeadAmps on January 17, 2023, 02:25:27 pm
Thanks tubenit, I'll save that schematic for reference in the future.

I'm happy with the amp and opted to have only a pre-amp out.
Title: Re: fx loop worth implementing?
Post by: jeff on April 09, 2023, 07:57:48 am
This is how I did my "active" FX loop on my Minimalist. I am very happy with how it works.


With respect, Tubenit


Hello, Tubeinit
Could I ask what is the transformer's primary impedance for your 6BM8 amp. What O.T. did you use.
My brother has a 6BM8 with a blown O.T. I'd like to fix for him(he's coming up for a visit in two weeks) and I'm not sure what to replace it with.
Thank you.
Title: Re: fx loop worth implementing?
Post by: tubenit on April 09, 2023, 08:42:39 am
I used a Tweed Deluxe OT with 8 ohm on mine.  I used an Edcor OT on another one I did.  Both sound great to me.


With respect, Tubenit
Title: Re: fx loop worth implementing?
Post by: jeff on April 09, 2023, 08:58:37 am
Awesome, thank you
That blue looks nice