ampage
Tube Amps / Music Electronics
For current discussions, please visit Music Electronics Forum. New: view Recent Searches.
New: visit Schematic Hell!
The sunn still shines online!

 
Listen to great tunes streaming live right now!

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  
previous: John J. R.G.,Before I build this Ph... -- 12/22/1998 3:01 PM View Thread

Re: "GEO" Phase 180 PLus

1/1/1999 8:20 PM
R.G.
Website
email
Re: "GEO" Phase 180 PLus
quote:
"Is it like the DOD Phasor 201? If not, what makes it different?"
 
I'm not familiar with the DOD 201. If you have the schematic for it, I'd be happy to compare the two for similarities and differences.  
 
quote:
"What type of op. amp. are you using? "
 
Generic. I used TL072's, but other duals in the industry standard 8 pin package will work as well. The original used 741 singles, TL022's, and I beileve 4558's at different times.  
 
quote:
"Does the placement of the Phase Intense interchange with the V.P.D. circuit? What are the differences of the two?"
 
You lost me. Can you expand the question?  
 
quote:
"What is the relation with the JFET matching Fixture? Where does it correspond to the circuit?"
 
It doesn't. You use the JFET matching circuit independently first to pre-select a set of four or eight JFETs that have approximately the same Rds/Vgs characteristics so that all the JFETs will be contributing phase shift at the same time, not just one or two. You'll probably need to buy at least twice as many JFETs as you use to get enough to select a matched set.

 
Replies:
John J. Ent.#3 Hay R.G.,Glad to hear from you.... -- 1/2/1999 9:13 AM