Manzamp!

[talbany]

In all the Dumble amps I have seen always have around 180-210 on V1 (one had 130) input/recovery,part of the Dumble/Skyline sound I would think!!..I can't think of any reason why he would deviate from those voltages..500v sounds a bit high for a Bassman power

Tony

Tony, I've got 503 on my Bassman MC PT 244vAC line voltage

Mark suggested why:
======================================

Hello Roger,

Please see the attached specification sheet for our 40-18029. Please see the actual measured voltages in the lower left hand corner. These are actual measured voltages with all windings loaded to FULL rated load currents. Each set of taps was tested with different rectifier tubes. The voltages were measured after the unit was loaded for a few hours...

All voltages will read higher with less than full load current, when the unit is cold, and when used with solid-state rectifiers.

Mark Sacketti
V.P. of Engineering

Magnetic Components, Inc.
===================================

30v zener on its way now, still the amp sounds really good, especially the cleans, just shooting for some Feedback City "zhoosh" or whatever it's now called lol. Playing with the NFB for now.

Roger
The 5F6 was designed to run on 110V AC and sometimes lower..It kills me when I get a transformer in designed around another famous amps transformer and the voltages are not even close.. I usually send them back.

Btw..Yep still the Feedback City amp. ..Passing on some feedback vibes for ya!!

http://www.jpbourgeois.org/guitar/pdf/A ... 205F6A.pdf

Tony

[ic-racer]

Thanks for all the comments. First youtube video. This is through the EV12S cabinet I got for my HRM. Recorded off the computer's mic.

The signal runs through a Fuchs Verbrator (used as a reverb pedal) prior to the input. This clip used the higher gain "NORM." input.

https://www.youtube.com/watch?v=b9qjeU0XBgg


For the voltage dropping resistors, I came up with 4 different combinations based on other amps with similar morphology.

The resistors I actually put in it when building it were actually based one the picture. The way I did it was by looking at the "E" series and realizing that only certain colors combinations will be possible in the estimated range. Even though they may be off, perhaps it would be a little better than just flipping a coin.

[martin manning]

Looks and sounds great, ic! Nice work- you went out on a limb here and it paid-off. Now, inquiring minds want to know what the rest of the schematic looks like... Pleeeeeeze?

[ic-racer]

This is the BRIGHT input with an SG. I see on Robben Ford's website he is using a SG now. So I had to get mine out. This one is a 1993 re-issue. It is hard to believe this "modern re-issue" that I bought new is now 20 years!

http://www.youtube.com/watch?v=PbLJk2dhFPo

[ic-racer]

Looks and sounds great, ic! Nice work- you went out on a limb here and it paid-off. Now, inquiring minds want to know what the rest of the schematic looks like... Pleeeeeeze?

See attachment!

[ic-racer]

I thought everyone that collects Dumble images has these but here they are again. Rob Livesey has them hosted on his site.

[IMG:604:800]http://img.photobucket.com/albums/v670/ ... nzamp2.jpg[/img]

[IMG:750:563]http://img.photobucket.com/albums/v670/ ... nzamp1.jpg[/img]

[martin manning]

Thanks, much appreciated!

[Structo]

Amazing you were able to go from those pictures to building the amp!

Thanks for sharing!

[Dingleberry]

That's an astonishing job you have done ic-racer!

I had empty chassis and transformers for 2xEL34 project so I couldn't help myself...
Power supply wiring is nearly completed.

-T

[ic-racer]

That's an astonishing job you have done ic-racer!

I had empty chassis and transformers for 2xEL34 project so I couldn't help myself...
Power supply wiring is nearly completed.

-T

Is this going to be another Manzamp? How are you going to do the main board? Eyelet board? Do you know how to etch copper boards? Do you want a pattern?

[LeftyStrat]

Thanks for your work on this. I may be starting on one myself. I've had the urge to build a 59 Bassman, but was actually thinking of using EL34's.

Interesting use of the inductor on the front end. Might be fun to have a multi tapped inductor to switch the midrange, like Ampeg amps.

Are you planning on a 4x10 cab?

[Mark]

Thanks for showing us your schematic. The clips sound good too.

I was a little confused by the choke 1-22Hy in the first stage. What does that achieve and did you include it in your amp?

[ic-racer]

Thanks for your work on this. I may be starting on one myself. I've had the urge to build a 59 Bassman, but was actually thinking of using EL34's.

Interesting use of the inductor on the front end. Might be fun to have a multi tapped inductor to switch the midrange, like Ampeg amps.

Are you planning on a 4x10 cab?

That is a coincidence, I just sat down to e-mail Brandon about a cabinet. I'm very happy with a Ported EV12S cab I got from him. Anyone reading this that makes cabinets and wants the job, let me know.
From the measurements I got off the picture, it looks like a standard tweed Bassman size and construction cabinet that is just different at the top to hold the unique chassis.

[ic-racer]

Thanks for showing us your schematic. The clips sound good too.

I was a little confused by the choke 1-22Hy in the first stage. What does that achieve and did you include it in your amp?

When I wrote that posted schematic up I was considering any value from 1 to 22 Hy. What I finally installed was three x 1Hy wired in series. So 3Hy in the amp presently.

So, the thought process is that the biggest axial chokes are about 1hy and he has more than one on the chassis. So, it is probably a series wiring. If he used parallel it would be to reduce the d/c resistance, but we already have the cathode resistor in the circuit, so the d/c resistance is probably not what he was tweaking by using 3 or 4.

Could he have used three or four 0.25 Hy chokes to make 1Hy? Yes ,but why bother when a 0.25 choke is as hard to find as a 1hy choke?

So, the components in the picture look like a few chokes or inductors stacked together. To figure out how they might work in the circuit I studied this diagram of an active tone circuit using a 22Hy inductor. What I did was to forget about the treble side of the tone circuit and just wired the bass side as a putative fixed bass boost.

Does it do anything in my circuit?

Personally, I am digging this amp so much I at the point of not wanting to touch or 'tweak' it one bit. I threw a set of used tubes on it for start-up and don't even want to change those out at this time. I have only played an amp sounding like this in my dreams.

[IMG:782:1023]http://img.photobucket.com/albums/v670/ ... ontrol.jpg[/img]
[IMG:801:1023]http://img.photobucket.com/albums/v670/ ... ntrol2.jpg[/img]

[Mark]

Thanks for your reply. What does it do in the amp?