Hi!
I am trying to build Gabevee's Maggie from http://members.tripod.com/~gabevee/maggie.html In fact, I had got the 6EU7 from him 2 weeks ago. But now I cannot seem to be able to contact him by e-mail, is it changed? Anyone has any idea?
Anyway, I have finished building the amp. However, I have a problem, there is a loud feedback sound in the speakers. Loud High frequency in one side, and a not so loud lower frequency in the other. This is gone if I disconnect the feedback loop. Does anyone know what's wrong? Without the feedback, the sound sounds funny, the bass is weak too.
I followed his schemetics exactly except for one of the coupling caps which is 0.047 instead of 0.04. Of course our irons are probably different.
Also my B+ is very high at 420V, so I used a 1K 50W (that's what I have at the moment) to drop the B+ to about 280V. I'll probably have to get a variable resistor or a lower valued one to get his specified 335V.
Appreciate any help from anyone with experience with this schematic or anyone at all. 🙂
I am trying to build Gabevee's Maggie from http://members.tripod.com/~gabevee/maggie.html In fact, I had got the 6EU7 from him 2 weeks ago. But now I cannot seem to be able to contact him by e-mail, is it changed? Anyone has any idea?
Anyway, I have finished building the amp. However, I have a problem, there is a loud feedback sound in the speakers. Loud High frequency in one side, and a not so loud lower frequency in the other. This is gone if I disconnect the feedback loop. Does anyone know what's wrong? Without the feedback, the sound sounds funny, the bass is weak too.
I followed his schemetics exactly except for one of the coupling caps which is 0.047 instead of 0.04. Of course our irons are probably different.
Also my B+ is very high at 420V, so I used a 1K 50W (that's what I have at the moment) to drop the B+ to about 280V. I'll probably have to get a variable resistor or a lower valued one to get his specified 335V.
Appreciate any help from anyone with experience with this schematic or anyone at all. 🙂
hi,
I was fortunate enough to repair one of these paraphase amps before. are you sure that there is a 390 ohm resistor connected to ground and to the 4.7K cathode resistor of the input tube?
you can also try reversing the connections of your opt tranny to the plate of the 6bq5 tubes.
hope this helps.
JojoD
I was fortunate enough to repair one of these paraphase amps before. are you sure that there is a 390 ohm resistor connected to ground and to the 4.7K cathode resistor of the input tube?
you can also try reversing the connections of your opt tranny to the plate of the 6bq5 tubes.
hope this helps.
JojoD
JojoD thanks!
That's exactly it!! I switched the OPT connections and everything is OK! Now music is playing... 😀
That's exactly it!! I switched the OPT connections and everything is OK! Now music is playing... 😀
hi,
you could play around with the cathode resistor to vary the 6bq5's plate current, at least you only have one resistor to play around with. 😀
enjoy!
you could play around with the cathode resistor to vary the 6bq5's plate current, at least you only have one resistor to play around with. 😀
enjoy!
increasing the value decreases the plate current and vice versa. I think the author tried a value around 100-150 ohms.
cheers
cheers
maggie copy
hi pengboon iam glad toy are enjoying your new paraphase
amp. I have an original maggie amp which continues to amaze
everone that hears it . BTY Ihave a schematic that I reverse engineered from it if anyone wants Ican post it . (circuitmaker 2000 pro format or jpg)
Iam considering builing another in a nicer package using iron from edcor.
Happy listening
hi pengboon iam glad toy are enjoying your new paraphase
amp. I have an original maggie amp which continues to amaze
everone that hears it . BTY Ihave a schematic that I reverse engineered from it if anyone wants Ican post it . (circuitmaker 2000 pro format or jpg)
Iam considering builing another in a nicer package using iron from edcor.
Happy listening
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