To Andrew Mod, or Not to Andrew Mod...

[vitor gracie]

Ok. I recently purchased a Formula Pre from a great guy here on the BB. (AndyK7XL)

I am a dual rec guy. Specificly a TremOVerb guy. Got mine new when it came out and had a 2channel head as well along with a studio pre and other boogie gear.

I wanted a more "Mark" sounding unit to pair with the 20/20 (which Im in the market for) I have read the Andrew Mod reviews and I know its an old topic, but I am really interested in it.

My question is to owners of the Formula pre...
To Andrew Mod, or Not to Andrew Mod?

I dig the looseness and mid range squishy hump the Formula has, it sounds like the infamous "Blues" mode in the TOV...but I cant get the unit to really do what I need. Its a little TOO loose. After playing dual recs for too many years...Im a little spoiled. I am sick of the "scoop" but I find that I need to scoop the eq on the formula to get it to sound like a GUITAR LOL!

I don't want to ditch it, just want some REALLY articulate description of the tone/response/feel of before and after the Mod from some fellow Boogie fanatics here.

Thanks Guys!

 

[vitor gracie]

Nobody?

 

[vitor gracie]

Bump....dang....no Andrew Mods out there huh? :roll:

 

[vitor gracie]

last bump...sniffle...sob... :roll:

 

[tubetone]

My Formula Pre was supposedly from an Eve 6 tour and do not know if it's been modded or not. All I know is that I love all the tones that I get out of it. tt

 

[mora_di2]

I've done some mod's to my own Formula. Not the actual Andrew mod though.

The clean on the Formula is great, but the distortion channels tend to sound both muffled and muddy.

1.I believe the muddyness/spongyness of the lead channels is from having too much bass in the pre-drive circuitry. My solution was to add a capacitor in series with the signal, I did this on the signal going "in" to the gain potmetres. This way I didn't have to mess with the circuit board itself, just soldered it between the cable and the potmetre. A capacitor works as a high-pass filter, and I could use different values for the two different lead channels. Actually I added a switch so I could switch between original, medium high-passed, and heavily high-passed. In the heavily high-passed mode the lead channel is now actually capable of quite heavy riffing.

2. The muffled part, comparing the Formula's schematic with it's combo-brother the Nomad series, I discovered that the Nomads have a presence control (wich is actually only a high-cut/tone control, not a "true" presence control), and so does the formula! It has the same circuit affecting both lead channels, but instead of a 1meg potmetre there is a resistor making it a high-cut (post gain, post mastervolume) compared to having the Nomads presence at a VERY low setting, almost zero I think. Solution for me was to add a potmetre, I've found I prefer the potmetre at nearly maximum so I will probably replace it with a resistor (with a much higher value than the original)

This has made the Formula a lot more usable for me.

 

[Ioanq]

hello, anyone have the schématics of the formula pré ?

 

[Ioanq]

Formula Schématics

 

[okgb]

Thanks for posting the schematics , I got one in a trade and don't mind the low end looseness , but
thats recording and not playing with a band , so reversable mods sound interesting ............
all in all I don't mind it , i need to play it more to know & decide , but I'd call it usable

 

[okgb]

Hey Mora , what cap values did you find usefull , in front of the gain controls ?

 

[okgb]

When I opened up my unit , I notice the gain control in the rythym channel was a dual pot where on the schematic
it appears as a single pot ? anyone know what is happening there ?