2Watt Sub Miniature Plexi

[JazzGuitarGimp]

hi guys,
I have most of my components mounted on my main board, yeah!
however I noticed that C33 is empty and I don't see it on the BOM which is what I have been using to populate my board with. Can anybody who has completed their board let me know what goes there?

thanks,
dj

Hey DJ, It's a 22nF, same as C34. I don't see it on the BOM either.

[dju]

Thanks, I hope I have an extra one laying around so I don't have to place an order.

dj

hi guys,
I have most of my components mounted on my main board, yeah!
however I noticed that C33 is empty and I don't see it on the BOM which is what I have been using to populate my board with. Can anybody who has completed their board let me know what goes there?

thanks,
dj

Hey DJ, It's a 22nF, same as C34. I don't see it on the BOM either.

[UR12]

Sorry guys, Thanks for catching this. I will update the BOM to add C33 on there. It should be .022.

[skyclmbr]

Guys

Got a PM about R32 being listed twice in the BOM. It should be a 470 ohm. Also been getting questions on the resistors for the PS board. I have included a pic of the populated PS board to try and help. Lou also found another small problem with the board in the PI area. I will address this shortly but I will test the fix before posting it here.

Hello Dana,

Just curious what the fix in the PI area is and whether you've had a chance to test it.

I played the Microplex last weekend and compared it to the "Cool Plex" model in Guitar Rig 5 (That's the best comparison I have, since I don't have an actual 1987 head). With the settings all the same, I get pretty much spot on the same sound. It sounds great! I'm now running it through a 4 x 8 cab with Jensen Mod 8's in it. I think the sounds is much more similar to the classic "Marshall" sound than my previous cabinet which had just a 1 x 12 Warehouse Guitar Speakers Reaper (Sort of a G12H30 clone) in it. I will try and get a recording down of the two and post it. My previous recording I made ended up with too big of a file to post, and I haven't a DAW to chop it up with...

Thanks and again, great job on the amp design!
Bryan

[alvarezh]

Here you go Bryan, it's free:

http://audacity.sourceforge.net/

All the best!

[MCK]

skyclmbr, congratulations on your great results!!!

I would love to see some photos of your amp as well as the 4x8 setup. This sounds way too cool. I always wanted to build something like that to go with my Lil' Devil but never got around to doing it. A MicroPlex full stack with 2 4x8 cabs would be great! How is the bottom end?

Thanks for sharing.

[skyclmbr]

skyclmbr, congratulations on your great results!!!

I would love to see some photos of your amp as well as the 4x8 setup. This sounds way too cool. I always wanted to build something like that to go with my Lil' Devil but never got around to doing it. A MicroPlex full stack with 2 4x8 cabs would be great! How is the bottom end?

Thanks for sharing.

Here's a couple quick pics.

(I'll also try and do a recording comparing the 1x12 to the 4x8, just to see if there's a bass difference)

[Reeltarded]

Neato!

If you want to make your plastic logo stick together at break points use a paper backing and even consider using a dremel to create a small channel between parts to glue in a stiff piece of wire if the paper isn't working by itself. You have to flow some superglue there and trim/clean the edges.

[LeftyStrat]

Did you build the 4x8? I've been thinking a 4x8 would be nice.

[skyclmbr]

Neato!

If you want to make your plastic logo stick together at break points use a paper backing and even consider using a dremel to create a small channel between parts to glue in a stiff piece of wire if the paper isn't working by itself. You have to flow some superglue there and trim/clean the edges.

Thanks for the tip! It cut off the rest of my comment, which was to say that I eventually managed to get hot glue, of all things, to stick to it, although it might have been because I sort of welded the two sides together. It's not exactly gorgeous but will work.

[skyclmbr]

Did you build the 4x8? I've been thinking a 4x8 would be nice.

Yup, built it out of 3/4 in marine-grade ply. It's definitely herky. If I remember, I can scan the measurements I used to cut the lumber.

[MCK]

skyclmbr, this is amazing! Looks great and I'm sure it sounds great too. Lets see how your bass comparison turns out. Thanks for all your sharing.

[M Fowler]

Looks great and 4x8 that I like.

[UR12]

Hello Dana,

Just curious what the fix in the PI area is and whether you've had a chance to test it.

Bryan

Hi Brian

There is an error on the board with the connection of the 2 1 meg resistors on the PI. First I want to publically thank Lou JassGuitarGimp for finding the error. The 2 1 meg resistors should be going from the grids of each triode to the junction of the 10k and 470 ohm tail resistors. The way the board was laid out they have them connected from the grids to the wrong end of the 470 or the cathodes of the PI. to fix this you just need to install R36 with it's top end soldered to the board normally and its bottom end not soldered to the board but connected to the bottom of R37 (10k) as pictured. R35 will need to be installed with its bottom end soldered to the board normally but its top lead needs to be connected to the bottom end of the R32(470) as in the pic. This will keep things wired corectly without having to cut traces or drill holes. I will incorporate this change along with the others on the newest version of the board. As far as sound, I really could hear much difference in the operation of the amp. Maybe a little more cleaner sounding cleans but that was about it. I'll be interested in what you guys think once you have done the mod.

[skyclmbr]

Hello Dana,

Just curious what the fix in the PI area is and whether you've had a chance to test it.

Bryan

Hi Brian

There is an error on the board with the connection of the 2 1 meg resistors on the PI. First I want to publically thank Lou JassGuitarGimp for finding the error. The 2 1 meg resistors should be going from the grids of each triode to the junction of the 10k and 470 ohm tail resistors. The way the board was laid out they have them connected from the grids to the wrong end of the 470 or the cathodes of the PI. to fix this you just need to install R36 with it's top end soldered to the board normally and its bottom end not soldered to the board but connected to the bottom of R37 (10k) as pictured. R35 will need to be installed with its bottom end soldered to the board normally but its top lead needs to be connected to the bottom end of the R32(470) as in the pic. This will keep things wired corectly without having to cut traces or drill holes. I will incorporate this change along with the others on the newest version of the board. As far as sound, I really could hear much difference in the operation of the amp. Maybe a little more cleaner sounding cleans but that was about it. I'll be interested in what you guys think once you have done the mod.

Hi Dana,

Thanks for the response. I thought that might be the issue you were talking about. Back when you and I talked about it, I put all the values into a Java calculator on ampbooks.com and played around with the two different wiring setups, it didn't seem to have any effect on the PI which seems to match what you said above. Nonetheless I'll do the mod and try and get some before-after recordings.

Thanks!
Bryan