Fender Hot Rod Deluxe/DeVille/Blues Deluxe rescue plan: HRD-to-ODS

[martin manning]

Did the burning Zener problem get solved?

[xtian]

Yes. Zener D15 is not needed. Was there for protection of PMU, only needed if supply voltage greater than 75v. Works fine without.

[JazzGuitarGimp]

Did the burning Zener problem get solved?

The switchibg power supply design calculations were based on the CE Distribution replacement Fender PT Spec Sheet. It turns out the bias winding of the stock Fender PT puts out quite a bit less voltage than the CED spec lead me to believe. The zener was placed in series between the rectified bias winding and the input of the switching regulator chip to drop 12 or so volts at the input to the switching chip in order to keep it under its Asolute Maximum input voltage. But since the stock PT was already well below the maximum allowable input voltage, the zener was not needed after all, and was replaced with zero-ohm component lead clipping.

[martin manning]

Thanks for the explanation, Lou.

[xtian]

Here's a quick demo, made in GarageBand. My Carvin SH645 plugged directly into the Monkeymatic Pinnacle (official name!). Shure SM47 just off center, one inch from grille, speaker is Eminence Wheelhouse 150.

First eight bars is clean channel, neck pickup. Second eight is lead channel with PAB boost, bridge pickup.

Monkeymatic Pinnacle demo1.mp3

[JazzGuitarGimp]

That sounds really nice, Aaron. Nice tone. Nice playing. Are you thinking it's done, or are you thinking about doing a bit more tweaking?

[xtian]

Thanks! I’m done. Faceplate should arrive next week.

[martin manning]

Sounds great, and it seems to like that speaker too.

[martin manning]

xtian, do you have an estimate of the total cost of this conversion?

[xtian]

xtian, do you have an estimate of the total cost of this conversion?

PCB "retail" cost is $79 plus shipping, from @jazzguitargimp

Populating the PCB with parts from mouser.com (my BOM is available for easy ordering) costs about $150.

Not included in the above: pots and front-panel switches, tube sockets and mounting hardware, hookup wire, new faceplate. New speaker if desired.

I estimate 8-10 hours required for labor.

[martin manning]

So with the board ($80), and parts ($150), there's probably another $100 in parts, $50 for a faceplate, and say $30 shipping. in total you'd be in for $410 for the conversion parts, plus a donor amp at $400-$500. If you add a new speaker, you'd be around $1100. Does that sound reasonably close?

[sirbergs]

If you can find a dead HRD, you should be able to get it for less than $400.


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[xtian]

So with the board ($80), and parts ($150), there's probably another $100 in parts, $50 for a faceplate, and say $30 shipping. in total you'd be in for $410 for the conversion parts, plus a donor amp at $400-$500. If you add a new speaker, you'd be around $1100. Does that sound reasonably close?

Sounds reasonable. My faceplate cost $32 including shipping. Should be here in a couple days.

What are you thinking, Martin?

[martin manning]

Just doing the math to compare this path and the traditional one. I guess the essence of it is the donor provides the chassis (needing a faceplate), transformers, cab, and some sort of speaker. It’s true a non-functioning or faulty donor would be the least expensive option, but may be a bit harder to find than a working amp. Even so, it seems that you would be ahead by a few hundred. It’s an interesting upcycling, and the result would probably raise some eyebrows at a gig!

[pompeiisneaks]

Just doing the math to compare this path and the traditional one. I guess the essence of it is the donor provides the chassis (needing a faceplate), transformers, cab, and some sort of speaker. It’s true a non-functioning or faulty donor would be the least expensive option, but may be a bit harder to find than a working amp. Even so, it seems that you would be ahead by a few hundred. It’s an interesting upcycling, and the result would probably raise some eyebrows at a gig!

yeah, I also can see if this becomes known that tons of people that started with one of these realizes how mediocre the tone is, and how flimsy the boards are, may want to jump on the option of an amazing upgrade for like what, maybe 700 or 800 bucks instead of having to buy a new amp for 1500 that's really worth it. even if they didn't initially think they wanted an ODS, or even know what an ODS is. (my guess of 7-800 is the 410 of parts you estimated, and some labor on top, for the 8-10 hrs for a tech to do the swap for you)

~Phil