AMPEG 6V6..........

[TIMBO]

Hi guys, A mate ask me to look into building a Ampeg amp.
Don't know much about them, other than they use some ODD tubes, SO..........

Any standouts that may use 6V6s (but not necessary), tremolo and reverb. Thanks

[sluckey]

Reverb Rocket... http://el34world.com/charts/Schematics/files/ampeg/Ampeg_r-12-r.gif

PS... I have a Jet J12-B. 6V6 with trem but no reverb... http://home.comcast.net/~seluckey/amps/RCA/RCA.htm

[vibrolax]

PS... I have a Jet J12-B. 6V6 with trem but no reverb... http://home.comcast.net/~seluckey/amps/RCA/RCA.htm

Well Steve,
I read your build description for the RCA conversion......."This will probably be a wrap for me."
Sure it was.  I always think my last project is a fitting wrap...then something starts itching again.
Jon

[sluckey]

I've said that several times! 

I've finally given in to the addiction. Nowdays when I hear "How many amps do you really need?" I say "Just one more." 

[TIMBO]

I don't have an Ampeg inspired amp so I WILL BUILD ONE MORE.

[goldtop1]

Hello, this is in reference to Sluckey's RCA conversion Ampeg Jet. I also have never owned a Ampeg amp. I saw this layout and thought I'd try to build. I used Magnetic Componenets transformers to start. I finished the amp and all is well except for one thing, the voltages on V-1 6SL7. All other voltages are within 10 volts of the ones on the schematic. Instead of 166v on pin 5, I get 324v. The power transformer Classic tone # 40-18016. The output is 330-0-330 with 400 V DC using a 5Y3GT rectifier. My voltages at the multican filter are Point A 413V,Point B 404V, point C 356V. All wiring checks out perfectly and the amp does work. Should it be as loud as my 5E3 Deluxe? I do have to turn it up all the way to get volume it does not break up, it seems like it should be much louder. It is about as loud as my 5E3 on 2. What would make the voltages so high on V1? Thanks for the help. First time using 6SL7 preamp tubes. The amp is nice and quiet and does sound good and clear , but needs more volume. 

[sluckey]

Instead of 166v on pin 5, I get 324v.

That indicates the tube is barely conducting which would also cause the low volume. How much voltage do you have on pin 6? I'm betting on a bad tube or the resistance from pin 6 to ground is much higher than 2.2KΩ. If the 120K plate load resistor is very high resistance you would get the same symptoms.

Get this fixed and you will have plenty of volume (unless there is another issue).

[goldtop1]

 Hey Sluckey, I checked voltages on pin 6 to be 4.5 VDC .

[goldtop1]

Also the resistance from pin 6 to ground is 23K !

[John]

Your cathode resistor is too high in value. You should be using a 2.2K. Those bands can be hard to read. Swap that out for the 2.2k and see what happens.

[goldtop1]

Thanks John for the heads up on this. The resistor I installed was a 22K red red orange. I installed a 2.2K red red red  and the voltage is much better. The volume did come up some, but not as loud as my 5E3 on 2. I ordered some new 6SL7 tubes from Doug, so will try those next. Thanks to all!!