Search found 297 matches

by JMMP
Tue Sep 11, 2018 11:44 pm
Forum: Modern Era Amps (1991-Present)
Topic: Fillmore Series
Replies: 5
Views: 3042

Re: Fillmore Series

Just received mine. My first impressions are a great clean. Only had time to play the amp for about half an hour tonight, I pretty much evenly split the time between clean and gain channels. After putting every knob on noon, the only knob I changed on the clean channel from the beginning was reverb....
by JMMP
Sat Dec 30, 2017 12:02 am
Forum: Rectifier Series
Topic: Mono vs. Stereo
Replies: 7
Views: 3699

Re: Mono vs. Stereo

Why not just go full on w/d/w? Panama makes some relatively cheap 112s with vintage 30 soundalike speakers, and they work well as wet cabs. Get a stereo power amp (50W per side?) and use the helix for stereo effects, with your choice of amp powering the center dry cabs. Mesa amps have the slave outp...
by JMMP
Mon Oct 30, 2017 7:40 pm
Forum: JP2C
Topic: JP2C rackmount reverb tank
Replies: 2
Views: 1994

Re: JP2C rackmount reverb tank

If it's like my rackmount Mark IV, the reverb is attached outside of the rack mount box. Mine was mounted to a plank of wood in a fabric reverb bag and sat in the back of the rack when I bought it (used). I have not seen a mesa rack kit with a way to mount the reverb to it.
by JMMP
Thu Jun 22, 2017 9:53 pm
Forum: Vintage Amps (Before 1991)
Topic: Redplating problem
Replies: 18
Views: 7310

Re: Redplating problem

Another update: replaced the two open resistors and the mark IV sounds better than when I got it! No redplating issues so far (I've only played with it 20 minutes at loud house volume), but under similar circumstances the mark IV would redplate before. I also changed out the EL34s for a new set, so ...
by JMMP
Wed Jun 21, 2017 11:19 pm
Forum: Rack Pieces
Topic: New Triaxis - PO's mod?
Replies: 2
Views: 1834

Re: New Triaxis - PO's mod?

Pretty sure that's to plug in your MIDI footcontroller's power supply so you can phantom power it with a 7-pin cable.
by JMMP
Mon May 29, 2017 6:32 pm
Forum: Vintage Amps (Before 1991)
Topic: Redplating problem
Replies: 18
Views: 7310

Re: Redplating problem

stokes wrote:Did somebody alter things in there before you got it?
Not to my knowledge, and it doesn't appear as if anything has been altered. Honestly, I was thinking that Boogie's schematic was wrong. I've read several times that their schemes aren't always the most accurate.
by JMMP
Mon May 29, 2017 6:17 pm
Forum: Vintage Amps (Before 1991)
Topic: Redplating problem
Replies: 18
Views: 7310

Re: Redplating problem

The problem is it's the outer sockets which are redplating. Is the lack of current going to pin 4 on the inner sockets able to cause the outer sockets to redplate? Also, while looking inside the amp, I noticed the 470 ohm resistors are not in series with the "2k7" resistors as shown on the schematic...
by JMMP
Mon May 29, 2017 4:50 pm
Forum: Vintage Amps (Before 1991)
Topic: Redplating problem
Replies: 18
Views: 7310

Re: Redplating problem

I finally got to mess around inside the amp again, and here is what I found: My bias supply at point E is -59 volts (Mesa schem says -57, but my value seems fine, and all the resistors up to that point measure well). After point E, so inside of the power amp schematic, the first set of 220k's measur...
by JMMP
Wed Mar 01, 2017 4:23 pm
Forum: Vintage Amps (Before 1991)
Topic: Redplating problem
Replies: 18
Views: 7310

Re: Redplating problem

Thank you all for replies. I have finally had some time to sit down with the amp and schem and try to sort it out. For starters, I took voltages again with no tubes in place, in simulclass/ pentode setting (on the clean channel, if that affects anything). The EL34 sockets read 495, 493, and -38 on p...
by JMMP
Thu Feb 16, 2017 7:47 pm
Forum: Rack Pieces
Topic: 2:100 modern mode...
Replies: 7
Views: 2261

Re: 2:100 modern mode...

Exactly. You can use a GCX or other loop switcher as well.
by JMMP
Mon Feb 13, 2017 10:43 pm
Forum: Vintage Amps (Before 1991)
Topic: Redplating problem
Replies: 18
Views: 7310

Re: Redplating problem

I just performed the voltage checks without power tubes installed and discovered an interesting mismatch. The EL34 sockets are mirrors of each other voltage wise. Pin 3 is at 506V, pin 4 at 504V, and pin 5 hovering between -38 and -39 V. I also checked the 6L6 sockets, and all is well there, too. Bo...
by JMMP
Mon Feb 13, 2017 3:52 pm
Forum: Vintage Amps (Before 1991)
Topic: Redplating problem
Replies: 18
Views: 7310

Re: Redplating problem

Thanks for the response! Those numbers were taken with the tubes in. I will remove the tubes this evening and take the readings you mentioned. I haven't been running it hard. It's pretty much always at louder house volumes. The resistor on the tube socket itself looks fine (a Dale wire wound resisto...
by JMMP
Sun Feb 12, 2017 7:27 pm
Forum: Vintage Amps (Before 1991)
Topic: Redplating problem
Replies: 18
Views: 7310

Redplating problem

Any technological minded folks around? I've been fighting a redplating EL-34 in the outer socket of my Mark IVb. It began only redplating when I would switch modes (either pentode/ triode, or Class A/ Simulclass), but now it redplates any time the Amp is on. I have tried swapping the outside EL-34s,...
by JMMP
Mon Jan 16, 2017 12:08 pm
Forum: Rack Pieces
Topic: Mesa 50/50 Considerably Weaker on One Side
Replies: 3
Views: 2078

Re: Mesa 50/50 Considerably Weaker on One Side

Did you check your speaker cables and speakers? Make sure they are plugged in all the way, and try swapping sides.
by JMMP
Tue Jan 03, 2017 10:06 pm
Forum: Vintage Amps (Before 1991)
Topic: Why did Mesa choose to EQ the Marks in the way they did?
Replies: 10
Views: 4843

Re: Why did Mesa choose to EQ the Marks in the way they did?

The marks are a direct descendent of Fender amps, and the eq knobs come before most of the gain. The higher you run the gain, the lower the bass should be because high gain on bass heavy tones leads to the fartiness. I have not owned any of the Marks you mentioned, but my previous Quad Preamp sounde...