Dumble 183 output transformer 2.2k

[Richard1001]

Hi everyone, I’m gearing up to build a Dumble 183 clone, and I called Chris Merren but he seems to be phasing out. I found amp parts direct and they seem to only offer a heyboer project 100watt out transformer with 2.2k primary resistance. I’m just wondering if anyone has used this transformer? How does it sound and feel when playing?
Also if anyone has a transformer that fits the bill and they be willing to sell, I’d be interested! Thank you

Recently i was looking for an output transformer and saw this one. It say's that it is made by Heyboer, but i find it odd that the physical appearance, impedance and secondary color coding is exactly the same as the Classic Tone 40-18072. Even the 'Heyboer' partnumber has the Classic Tone partnumber in it. (APD-8072 H).

I have used this Classic Tone transformer for my SSS and it sounds excellent with both clean and distorted tone. I use it in a 4 x 6l6 poweramp.

This is the description of the 40-18072 transformer:

This is a vintage constructed, paper layer wound output transformer. This multi-purpose output transformer is meant for use as an upgrade / replacement output transformer for many modern, high gain style amplifiers as well as many vintage style amplifiers. This is also an amazing, high performing DIY output transformer. This output transformer is based loosely on the one used in the Marshall 100W Plexi, JMP and JCM800 amplifiers (or ClassicTone # 40-18026) but has additional features. Physically, it is larger and has more substantial, beefier mounting brackets (see Specifications for details). As far as performance, it offers wider bandwidth than normal production guitar amplifier output transformers and is supplied with the best available, grain oriented M-6 steel for the ultimate in tone!

[pottedplant]

For least coupling the magnetic axes of the PT and the OT should be at right angles.
The magnetic axis is defined by the coil. As the coil winds around the center leg of the core, you want the center legs of the transformers to be at right angles for least coupling.
So you need to guess or know the orientations of the core center legs (or the coils).

Your PT and OT have their magnetic axes in parallel.
This favors magnetic coupling and may cause induced 60Hz hum (even without power tubes inserted).
I'd consider rotating the OT by 90°.

Which one has the axis' in parallel according to you? I tried finding what you were talking about but I'm unsure. In the images above it all seems like they're perpendicular but you see one that isn't so I am very curious to learn which one to expand my knowledge

[Helmholtz]

Which one has the axis' in parallel according to you? I tried finding what you were talking about but I'm unsure. In the images above it all seems like they're perpendicular but you see one that isn't so I am very curious to learn which one to expand my knowledge

I was referring to the pictures shown by 67plexi.
An E-I core has its magnetic axis in parallel with the smaller sides.
So the smaller sides of PT and OT should be at right angles.

[pottedplant]

Which one has the axis' in parallel according to you? I tried finding what you were talking about but I'm unsure. In the images above it all seems like they're perpendicular but you see one that isn't so I am very curious to learn which one to expand my knowledge

I was referring to the pictures shown by 67plexi.
An E-I core has its magnetic axis in parallel with the smaller sides.
So the smaller sides of PT and OT should be at right angles.

Is his not laid out the exact same as the "best" configuration? I'm confused that's why I'm asking

[67plexi]

My power transformer is turned 180 degrees what a Marshall is dead silent no hiss or hum the magnetic flux is not strong enough
to interfere with the output transformer that said on my 150 watt SSS build I did have to move the output transformer 90 degrees

amp 0001.JPG

[Helmholtz]

The amp in the photo has the transformers with their shorter sides in parallel. Means that the coils' axes are in parallel.
That's not optimal.
Would better with the OT rotated by 90°.

[pottedplant]

The amp in the photo has the transformers with their shorter sides in parallel. Means that the coils' axes are in parallel.
That's not optimal.
Would better with the OT rotated by 90°.

I guess I'm just really dumb because I do not understand what you mean by shorter sides

[Helmholtz]

I guess I'm just really dumb because I do not understand what you mean by shorter sides

Shorter side is the one with the dimension F in this picture:
http://jamestransformer.com/uploads/all ... mer-3d.jpg

[pottedplant]

I guess I'm just really dumb because I do not understand what you mean by shorter sides

Shorter side is the one with the dimension F in this picture:
http://jamestransformer.com/uploads/all ... mer-3d.jpg

ah okay i see now, thank you. this makes sense. the coil is below it!

[Helmholtz]

Here you can see the E shaped laminations with the center leg, which is in parallel with the shorter side:
http://jamestransformer.com/uploads/all ... nation.jpg

[pottedplant]

Here you can see the E shaped laminations with the center leg, which is in parallel with the shorter side:
http://jamestransformer.com/uploads/all ... nation.jpg

this makes sense, for some reason i was presuming the center leg was perpendicular to the shorter side as it's called. thank you for clearing things up!

[WhopperPlate]

Late to the party, but fwiw 2k2 with 4x EL34s 100 watt sounds fantastic. I like the slightly higher primary impedance in every circuit that I have applied it within.

[martin manning]

Late to the party, but fwiw 2k2 with 4x EL34s 100 watt sounds fantastic. I like the slightly higher primary impedance in every circuit that I have applied it within.

You're not the only one. The low primary impedance Marshall used on EL34 amps was ok in the JMP era, but sticking with it after voltages went up to 460+ was a mistake, IMO.