Vintage Mark-style PCB and chassis kit

[Hoplite22]

Amazing work, btw. Looks amazing so far !!

 

[Hoplite22]

Here's a couple other questions:

1. Long head format or short head?
2. Simul-class or 60/100
3. 4/8 or 4/8/16 ohm speaker taps?
4. 120V 60 Hz only, or 100/120/240 50/60 Hz?

Personally I like the short heads, but either way is ok. Having the presence at the front is way better actually.
Simul-class is great, but the JP2C is 60/100 and that thumps !!
I think the 4/8/16 ohm option is a must.
And seriously, the 100/120/240 OT is the answer !!!!
Opens up your customer options, and I speak for many gere in Australia, that they would definitely want to buy one of these with these options !!!

 

[Jay Omega]

Personally I like the short heads, but either way is ok. Having the presence at the front is way better actually.
Simul-class is great, but the JP2C is 60/100 and that thumps !!
I think the 4/8/16 ohm option is a must.
And seriously, the 100/120/240 OT is the answer !!!!
Opens up your customer options, and I speak for many gere in Australia, that they would definitely want to buy one of these with these options !!!

If only folks would have responded to my post on Oct 19 last year, you very well may have got all you’re asking about. The ship has sailed at this point my friend!

 

[Jay Omega]

Been working on a design for a long head cab that I may offer separate from the kit. They would be unfinished for sure, maybe flat packed, and cut from voidless baltic birch on a CNC. Here is a rear view

 

[Jay Omega]

Chassis have FINALLY been ordered today. I'm ordering 11 but building 2 for myself, so there will be 9 available for sale. Shop said end of May estimated ship date, so when they arrive I'll build the first one and make sure everything is all good before taking any orders.

Slowly but surely getting closer!!

 

[Jay Omega]

The test build has begun

 

[Jay Omega]

Here is the power supply card populated

 

[Jay Omega]

The EQ board:



Power amp is next

 

[rarebitusa]

It's based of a IIC+ DRG, but incorporates some features from later Mark series amps.

I don't think I've ever seen a complete, or accurate schematic of the old Boogies before. You may not appreciate it but I consider it a feat, a lot of time went into it, but moreover I felt it was necessary due to the features I added that weren't included in the originals.

Yea man it's a feat no doubt. Kudos to you for not only doing the project but sharing the journey.

I am curious what "features from later Mark series amps" have made their way into this design?

 

[Less02]

It seems like you have plenty of time! Really impressed about how accurate is your replica!

 

[Jay Omega]

Yea man it's a feat no doubt. Kudos to you for not only doing the project but sharing the journey.

I am curious what "features from later Mark series amps" have made their way into this design?

I added the mid-gain / harmonics, pentode / triode, and the “extreme” mode as switchable functions. The power amp PCB has pads to make a DC supply that could be used for things like DC heaters on V1 or to power a relay.

I also put the presence control on the front, and reverb on the back as presence is a setting I tweak much more than the reverb. I also put external switching jacks on the back as well as underside of the chassis so either can be used.

Another thing is square holes for clip nuts to mount the chassis like the JP-2C rather than the welded nuts you’ll find in the old marks. That way if you accidentally strip the nut it isn’t a big deal

 

[Jay Omega]

It seems like you have plenty of time! Really impressed about how accurate is your replica!

I wish I did! It’s taking vacation time from work, sneaking off when the kids nap, or sacrificing sleep. Or further procrastinating yard work or doing my taxes. It’s only a matter of time until the chickens come home to roost, but I have to take advantage when I’m feeling motivated

 

[Jay Omega]

Probably as far as I need to take this before installation

 

[Jay Omega]

Some good news, just got the invoice for the power transformers so they should be getting ready to ship. Will post some pictures of when they arrive!

 

[rarebitusa]

Very cool... going to assume you've bench tested some of the PCBs to some degree?

 

[Jay Omega]

Very cool... going to assume you've bench tested some of the PCBs to some degree?

This build is the guinea pig!

 

[rarebitusa]

This build is the guinea pig!

I was being nosy, just scrounging for details

 

[Jay Omega]

First few transformers arrived today, here is a new one next to the no stripe with a 105.



Cores are pretty much bang on. I’m happy with how they came out

 

[Jay Omega]

Quick update - I have been unable to identify any readily available LDRs that have acceptable performance with the stock IIC+ circuit. Due to this challenge, and the dwindling supply of NOS Vactec VTL5C1s and VTL5C4s, I would only suggest my initial preamp board to those that can source Vactecs, or more experienced builders that are able to modify the stock circuit if appropriate to work with alternative LDRs.

For less experienced folks, or those that can't find original Vactecs, I plan to offer a relay-based preamp board as an alternative. While designing, I've added an optional feature that is not available with the LDR boards which is automatic activation of the Bass Pull Shift feature while in the rhythm mode. I never use the Bass Shift in the lead mode but always like it on when playing clean. The biggest downside of the relay based board is that the amp will not activate the LED if using an original Boogie Mark II foot switch.

I will be building one of these as well with my test builds before accepting any orders, here is a sneak peek of what it will look like

 

[Less02]

When I have built the mkiv clone, my second prototype was using relays. You might experience some popping noise when switching chanels, unless you mute the amp like the newer models during the switching.