Merlin Loop in a 2204

[fusionbear]

Hello Gents,

So I installed the Merlin loop on page 266 of my copy of "Designing Tube Preamps for Guitar and Bass" 2009'

This is the one that uses the 12AT7 Tube

It works really well. The only mod I had to do on my amp is add a 10K resistor in between the Wiper of my 25K PEC pot and the .01 coupling cap that feeds the "send" part of the circuit in order to prevent overload. The rest of the circuit is the same. I took the B+ right from the B+ of the tone stack Cathode follower. I had to do this left handed and it took me all day because I had to ask for help in moving and installing the chassis back in the head shell. (Not supposed to lift anything with my right yet)

Enjoy:

Before:

[IMG768]http://i169.photobucket.com/albums/u223/fusionbear/2204%20influenced%20build/IMG_3399_zps50420c91.jpg[/img]

After:

[IMG768]http://i169.photobucket.com/albums/u223/fusionbear/2204%20influenced%20build/IMG_3400_zpsa6b791d9.jpg[/img]

[IMG768]http://i169.photobucket.com/albums/u223/fusionbear/2204%20influenced%20build/IMG_3402_zps0d9ee030.jpg[/img]

[IMG768]http://i169.photobucket.com/albums/u223/fusionbear/2204%20influenced%20build/IMG_3404_zps00ad188e.jpg[/img]

It is very transparent and quiet. You can see the page I copied from the book and followed. The amp really rocks!

Thank you Merlin!

[Blindog]

Nice! Super clean build.

Mark

[cbass]

Did you replace the sd60 loop with this one? How do they compare? I have a bunch a at7s that need uses.

[fusionbear]

Did you replace the sd60 loop with this one? How do they compare? I have a bunch a at7s that need uses.

Yes, and it is better IMO...

[cbass]

So does the send control on the loop function as your MV now?
I see you went with the old school presence resonance circuit. I swapped back and forth a couple of times in my SD before I got the SD presence control dialed in like I like it.

[fusionbear]

I thought the sd 60 sounded best with their presence circuit. But a 2204 sounds best to my ears with the old school stuff.

[cbass]

So where is the MV now? Does the send level on the loop serve as a master?

[fusionbear]

So where is the MV now? Does the send level on the loop serve as a master?

Yes, I replaced the PEC 1M master pot with the 25K PEC Master pot. It is different in that most loops are between the treble pot and the master pot. I will play with this for a while and see if I like it in the long run.

I really like the Metro loop. It is really hard to top that one IMO. But, this one is working really well so far. My only concern is that I wonder if it will overload the input of effects if I turn up the new 25k MV pot to the higher settings.

[fusionbear]

Being that I like the circuit to be as simple as possible. Merlin suggests going straight to the send jack from the new 25K MV pot. I went ahead and did that this morning and like it even more. So, the isgnal goes from the wiper of the 25K pot to the send jack. Return jack goes to the recovery part of the circuit to the one half of the 12AT7. I like the way this sounds even more... Less coloration for sure. This is as good as I think I can get it...

Before:

[IMG768]http://i169.photobucket.com/albums/u223/fusionbear/2204%20influenced%20build/IMG_3403_zps7a1b7d68.jpg[/img]

After:


[IMG:640:480]http://i169.photobucket.com/albums/u223/fusionbear/2204%20influenced%20build/IMG_0650_zpsd8d31f6a.jpg[/img]



This is from page 266 in Merlin's book previously noted.