Partridge type transformer set in Marshall 1987 type build

[Gtr0]

Hi MEF'rs.
I have an old Lanely LA60BL, from the late 60's. In most ways it is very similar to a late 60's Superbass circuit except perhaps v1 Rk components. I also already have several Marshall type builds... a JTM45, a 1987, a 1959, and 2203 circuits. What I love about the Lanely is that the sound is generally fatter and more clear - especially in the bass and low mid frequencies. Highs seems to be a bit more mellow as well, but it could be the circuit doing that. I can only assume that a big part of the reason would be the Partridge output tranny (TG9686) and a much higher B+ (hovering 570-600VDC from memory).

Would this be a proper assessment? Is this output transformer considered to be more "hifi" than the standard Drake/Dagnalls of the late 60's/70's?

I am trying to understand output trannys better... winding styles etc and their resulting characteristics. But it is a lot to take in.

Anyway, I am thinking of putting in as similar a set of transformers that I can find to these partridge trannies into a new 1987'ish build I am starting to collect components for. What I have found is that the transformers that usually come recommended (new production, probably Inmadout) for a Hiwatt DR504 may do the job as they seem to have similar characteristics (on paper)...

As seen here: https://www.tube-town.net/info/daten...4-pw-v2020.pdf
Power Tranny for HiWatt DR504
Secondary: 350 - 0 - 350
Filaments: 3.15 - 0 - 3.15
Bias: 50V

The dedicated bias tap is a nice feature.... but if I am correct, rectified power should come to just under 500VDC. Correct? (700 x .71 roughly)

Output tranny for Hiwatt DR504 - https://www.tube-town.net/info/daten...t-dr504-ot.pdf
Primary: 3k8Ω
Secondary: 4, 8, 16 ohm
Max: 75 watt

I hope that a standard 3H, 100mA choke would work in this scenario? Or would I require something... beefier?

To be used with a set of EL34, new production. I typically use TAD or Harma since I have had much less failure rates than factory branded, off the shelf stuff. Actually as far as TAD and Harma both go, I have yet to have a failure after a few years.

So, am I barking up the right tree here? Thanks for your input... I would feel better to know I am making an okay move here. I am not afraid to face replacing them if it doesn't work out sonically... but I never like to just jump in the deep end on my own limited knowledge and experience.

[Helmholtz]

I think to find out what difference an OT makes, you need to compare them in the same circuit.

Everything else would be just speculation

E.g. bigger core doesn't necessarily mean a better transformer and a technically better transformer might not "sound" better in a guitar amp.

Also OT manufacturers never publish complete data including main inductance (depending on voltage and frequency), leakage inductance, effective primary capacitance, saturation limit and others

So even a look-alike clone might perform different from the original.

[Gtr0]

I think to find out what difference an OT makes, you need to compare them in the same circuit.

Everything else would be just speculation

E.g. bigger core doesn't necessarily mean a better transformer and a technically better transformer might not "sound" better in a guitar amp.

Also OT manufacturers never publish complete data including main inductance (depending on voltage and frequency), leakage inductance, effective primary capacitance, saturation limit and others

So even a look-alike clone might perform different from the original.

Good advise. Thank you.

I find myself leaning back to what I know, or have experienced, and I already have a good set of trannys that are made for this circuit specifically. So I am gonna "fold" and leave "more than well enough" alone.

Thanks for the reply!