Manzamp!

[Mark]

HAD must have built more ODS and SSS so having chassis' made wasn't an issue, I assume the demand wasn't there to have chassis made for this amp. I can't but help think a different chassis might lowered the price of the amp.

Your amp is starting to shape up and looks great.

[ic-racer]

This is what I have found out with respect to speakers. It looks like the Manzamp used two MusicMan alnicos 10" speakers and two MusicMan ceramic 10" speakers.
I have not been able to find these speakers, but I did find pictures of them. I am under the impression they are Eminence speakers so I'm planning on using modern Eminence speakers. If I ever find these original type speakers, I can always swap them out.

[IMG:500:374]http://img.photobucket.com/albums/v670/ ... Alnico.jpg[/img]
[IMG740]http://img.photobucket.com/albums/v670/ ... eakers.jpg[/img]

[ic-racer]

These are the speakers I have in mind as suitable replacments:
[img640]http://www.essentialaudio.com.au/conten ... k_back.jpg[/img]
[img640]http://www.essentialaudio.com.au/conten ... 8_back.jpg[/img]

[dreric]

When were the Manzamps built?

Based on the yellow resistors and the Manzamp listing in the 1990 Dumble price list, I put it in the 1980s. The Music Man speakers are from the 1980s also, I believe.
Manzamp = $8,500 express service
SSS = $8,500 express service.
ODS Head = $5,150 express service.

Something about the Manzamp made him price it the same as the SSS.

I would speculate that the use of hand made printed circuit boards in the Manzamp and the SSS would be a factor in the cost. I'm bootlegging the SSS with jumpers and I can see that there is a lot more thought in the board design. Much less forgiving to work with. Given that the two SSS that have been revealed have significantly different boards it seems that HAD was still thinking out, voicing and manufacturing these boards for each build.

BTW your build, attention to detail and commitment on this amp is awesome.

Eric

[talbany]

IC
I Personally would go with the Legend..You will find those E Alnico to not have near the headroom or punch as those early MM Alnico Eminences..BTW The Legends were designed to replace the early Fender BF speakers (Oxfords...etc)

Good Luok and looking forward to the schematic..

Tony

[ic-racer]

A MusicMan 4x10 Amp with 4 of the Alnicos came up on Craig's List but the seller won't reply to my emails. Maybe it is sold already. I'll keep looking.

[ic-racer]

I soldered all the component in to the board. In Dumble style, I put solder over all the copper. I did half of it slowly until I reailzed I had a 40W iron. It went much faster with the hotter one.
[IMG768]http://img.photobucket.com/albums/v670/ ... ile-71.jpg[/img]

[ic-racer]

I started wiring the pots. These are the two volume controls showing the 270k resistors, right on the pots.
[IMG768]http://img.photobucket.com/albums/v670/ ... ile-72.jpg[/img]

[ic-racer]

No looking back now. The main board is getting soldered in place. When I started thinking about the layout, I had considered making all the wires long enough so I could lift the board out and access the back without unsoldering anything. I don't think that will be practical. What I did to was to mount components of questionable value on eyelets so I can change them from above.
[IMG768]http://img.photobucket.com/albums/v670/ ... ile-73.jpg[/img]
What you see in this picture, from Right to Left:
Red = Power from the rectifier tube
Yellow x2 = To and from standby switch
Red = Output transformer
Black x 2 = To and from choke
Yellow = to screens
Then the first dropping resistor.

[Mark]

It's looking good, it is funny to see the old style pcb's, with the single copper clad side and no through hole plating. The new pcb's are a pleasure to work with of course making a modern pcb is cost prohibitive, mind you it would be good to have a pcb with earth planes and all the other luxuries.

[10thTx]

Remarkable build! I appreciate your sharing and will continue to look for more posts.

Thanks, 10thtx

[martin manning]

ic, I know you said you'd eventually reveal all on this project, but can you explain the philosophy of the Manzamp? It looks like a 5F6A, but can you say (in general terms) how it differs in its topology and circuit? Does the catalog listing reveal any of the thoughts behind it?

[Mark]

I started by breaking the board down into those identifiable zones.
Within each zone I tried fitting the 5F6 components.
When things did not fit, I used Dumble circuits.
90% of it was straight forward. The last 10% took a few months.

In a nutshell:
Start with the 5F6 schematic.
Add a Precision Power supply.
Add Skyliner Tone stack
Add Dumble style presence and alter PI values and NFB values.
Add EL34 tubes
Make V1 a 12ax7
Add adjustable Bias
Bypass V2 Cathode
Elevate heaters with resistors to ground.
Change the values of coupling caps to match the size of the components on the schematic. For example if two orange caps on the picture are the same physical size, I made them the same value on the schematic.
Re-do the input wiring
Add a few unnusual component (more on that later )

I think this was on page 3. Is this what you meant?

[tubedogsmith]

the power supply is a pretty huge difference from the original narrow panel bassman setup.

[martin manning]

Thanks Mark, I do recall reading that description now. Re the power supply, it looks like there is a lot more reservoir capacitance, but otherwise the precision power supply isn't much different, electrically speaking. Dumble-style presence is Fender presence. I'll be most interested to see the other circuit details when they are finally unveiled...