Manzamp!

[M Fowler]

Yes the Mojotone CTS and Alpha for Mojotone are all .375 I use those because they work well with chassis/faceplate situation.

[Gaz]

Bourns from Apex Jr. Are also .375 length. They are have them at mouser too.

[ic-racer]

I ordered the transformer set. My last two builds used Hammond. I thought I'd try something different and went with Classic Tone.


1 40-18003 Vintage Fender 4Hy, 90mA DC Style Choke 40-18003

1 40-18073 Fender Tweed Bassman Style, 40W / 50W Power Transformer 40-18073

1 40-18083 Fender Tweed Bassman, 50W / 60W Output Transformer 40-18083

[Mark]

Amazing, I can't workout how you got so much from that photo.

Keep it coming, it looks interesting and it will be good to compare it to a 5F6a Bassman. To my eye this is the amp it most resembles.

I have heard a lot of good things about the Classic Tone transformers.

[ic-racer]

Amazing, I can't workout how you got so much from that photo.

Keep it coming, it looks interesting and it will be good to compare it to a 5F6a Bassman. To my eye this is the amp it most resembles.

I have heard a lot of good things about the Classic Tone transformers.

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 )

[tictac]

Do you really mean a 5F6 Bassman and not a 5F6-A Bassman?

They are different circuits. The 5F6-A circuit is the one Jim Marshall used for the JTM45 amps.

TT

[John_P_WI]

In a nutshell:
Elevate heaters with resistors to ground.

???? Guessing this is a typo, or I am not understanding. Generally heaters are elevated 50 v or so using a voltage divider off of one of the power supply nodes.

[tictac]

With the Fender Tweed amps and most vintage amps with a center-tapped heater winding the center-tap is grounded not elevated...

The circuit ice-racer is recommending deviates from the norm and he's pointing that out...

TT

[John_P_WI]

Thanks for the clarification Tictac.

[Mark]

Thanks for the explanation Ice. It's a credit to you, you've worked long and hard on this project.

I think I'm even more curious how the Manzamp will compare to a good Fender 5F6a Bassman. It's an iconic amp in it's own right.

[Aaron]

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 )

Looking at the P.I valves and components I'm guessing maybe Odyssey inspired, so valves might be like this:-

V1 - 12AX7 (both sides for inputs)
V2 - 12DW7 (AX7 side as tone stack recovery, AU7 side as P.I driver)
V3 - 12BH7 (P.I)
V4,V5 - EL34
V6 - GZ34

Also, looks like resistors in parallel as a choke????
Just thinking out loud

Aaron

[Mark]

V3 - 12BH7 (P.I) V4,V5 - EL34

Again thinking out loud, I'm not sure you'd need a 12BH7 with the EL-34's. The plate dissipation is 3.5 watts and the gain is 16.5.

http://www.drtube.com/tubedata.htm

What is a Manzamps claim to fame other than being built by HAD?

Is it about clean tones or distorted tones?

[ic-racer]

I'm guessing maybe Odyssey inspired, so valves might be like this:-..

Aaron

I have left the V2 nearly stock 5f6a likely with the plate resistor on the socket. The layout and wires to the socket (from the power supply directly) seem to support that.

[ic-racer]

Do you really mean a 5F6 Bassman and not a 5F6-A Bassman?

They are different circuits. The 5F6-A circuit is the one Jim Marshall used for the JTM45 amps.

TT

After the alleged Dumble modifications to the schematic the remaining parts of the schematic could be from either of the two.

[ic-racer]

What is a Manzamps claim to fame

It may not be 'famous.' or good sounding. I'm not sure anyone here knows
Main reason I'm doing this is this is a rare amp and no one (that posts here) has done one yet. I'd say 90% of the expensive parts involved in this build can used to make a good 5f6A in this same chassis ( in case this turns out to be a sonic failure )