u/Nervous_Suit_5799

Been working on these series 400 amps for a while I decided I should get some for myself, got the PA-600 a while ago for my DAWless setup, it’s still undergoing restoration, and got a solid deal on this MK III Musician with the 2x15 cab today, and had to scoop it up, it was the last piece I needed too to make a video about the series 400 amps which I’ve been planning. Now it’s time to queue it for the workbench and get it up and running and cleaned up!

VERY long story so I’ll keep it short and sweet, I’ll be making a full video about this whole job experience soon.

Basically had a client needing service on a pair of Beolab Pentas where the right speakers amplifier at the base died and experienced some protection lock issues as well after attempting the full service, client took my recommendation to just convert to the Beovox factory configuration without the amps, since he’s sending an amplified signal already from his console. Well I went to reinstall the converted speakers for him and after some testing the remote stopped working, we unplugged the amp to reset to try and fix it and it simply wouldn’t turn back on, the amp didn’t blow or anything but the relay controller has been slow roasting for years so when we turned it off it did not want to turn back on, as you can see by the cooked R34. Because of cascading failures on a less than serviceable ecosystem he made the decision to retire the whole stack, keep the passive Pentas and hook them up to his other newer living room system. And he decided to just leave the whole stack with me to just do whatever with and poke around at when I have time. So I’ll eventually get the amp back up and maybe have a decent Beosystem to work with. A VERY stressful and problematic job ending up with a decent resolution. Frankly I’m most excited about trying out the turntable.

Full stack:
Beomaster 5500
Beocord 5500 x2
Beogram CD 50
Beogram CD 5500
Beogram 5500
Beomaster MCP 5500
Beosystem remote

Just finished diagnosing this pioneer for a client and repairing some motorboating in the phono preamp stage. Running and sounding great now, doing some testing with a little Coldplay on vinyl.

Here’s the complete rebuild parts survey. Everything can be found at this link: https://www.dksoundparts.com/product-category/beolab/beolab-penta/

It’s looking like the bridge rectifier on the problem tower has gone bad, so I’ll also be replacing that, but I caution at the difficulty of removing the screw mounting it to the heatsink. I also encourage purchasing the rubber transformer bushings, they will be dry rotted most likely and disintegrate upon removal.

After repairing a series 400 Bass for a client, I got inspired to pick this bad boy up since I was very happy with the amount of empty space inside with tons of modding potential, this is going to end up being the centerpiece of my DAWless home studio setup.

Some milder settings with a nice touch of tube driven reverb

Just got these gigantic powered towers in for a restoration after the right speaker stopped working, turns out it’s just a bad relay and some bad filter caps, doing a full refurbishment on both to get them sounding like new again, but the tower that did still work sounds excellent. Currently awaiting parts and will post updates this week hopefully.

Finally packaging the first batch this week, preorders go live at midnight tonight on Cynapticaudio.com and will have a demo video up as well on YouTube. I appreciate this groups support while finishing up this project, and hope some of you guys will get a chance to experiment with this platform!

Since I posted some pics of my modular germanium fuzz, figured it’s time for a sound check before preorders go live.

Currently designing a modular Fuzz Face clone that with one board can accommodate NPN or PNP transistors with just a switch. This is the current board revision and what will hopefully be the last on the way! Using all NOS vintage semiconductors (Ge and Si)

Client dropped this off recently with no signal, got it cleaned up, and new electrolytics all the way around. It absolutely rips and the built in fuzz is quite nice, tested it with a guitar rather than a bass however.

Lots of awesome handwired gear on this sub so I figured I’d show off some of the custom PCBs I’m prototyping; an LED clipped distortion and a germanium fuzz that can be swapped between NPN and PNP transistor modes with just a switch. Newer revisions are on the way, these are the second revisions of both designs.