Is A Diy Fender Vibro King Doable?

[RobKay]

Is a diy Fender vibro King doable, not seen any chassis or anything for one, info seems a bit scarce.
Regards
Rob

[Stevem]

Chassis wise a super reverb would work out fine a long with a custom faceplate.

Kits I have not seen so your on your own in terms of gathering up parts.

[sluckey]

Here's my Vibro King clone...

https://sluckeyamps.com/misc/Sluckey_Vibro_King.pdf

[solderhead]

It's entirely do-able. Basically the amp that you're building is no more complicated than building a 6G13 reverb unit into the left channel of a Bandmaster without NFB. The hard part, as you noted, is that the Fender documentation is scant. They haven't released the full service manual that has the layout diagram.

I made my own turret board out of G10/FR4 and that was the hardest part of the build -- determining the layout was the lion's share of the work. I gutted a Bassman 10 and there was plenty of room inside. As it turns out my B-10 used the same chassis that Fender used for the Super Reverb and Bandmaster as the chassis already had all of the holes punched for all of the SR controls and they just covered them up with a different faceplate.

If you need a chassis I would go looking for a B-10 as you're likely to find one a lot cheaper than a SR or Bandmaster. The B-10 uses the same PT as the SR but the OT is different. I replaced the original B-10 OT with a full-sized 50W OT that had multiple taps. I would build the version that uses the 6V6 in the reverb section and not the EL84. Fender went to the 6V6 because of EL84 failures. You might also consider building the amp with NFB that can be disabled as that makes the amp a lot more flexible.

Sluckey has a very nice layout there -- I wish that I had access to that when I was building my amp. If I were building my amp today I would definitely use his layout. (Interesting that he used a vactrol.)

[Roe]

Doable but the speakers and OT combo is unusual. The OT is a 5f6a type with 4k2 primary and 2ohm secondary, connected to three 8 ohm speakers in parallel for a 2.7ohm load (that gets reduced to 1.6ohms if you add the 4 ohms extension cab)

[rccolgan]

Let me know if you guys need any photos or anything of a revised Vibro-King with the 6v6 reverb. I have a mint one that I recapped recently in my personal collection. I am also a big Gary Clark Jr. fan so I grabbed some info on one of his that a tech went through. Let me know if you need more photos to create a layout.

I think you'd need to use the transformers as well for the 6v6 driver? I don't know if that's part of the calculation or not for ya.

https://photos.app.goo.gl/aPhQYg6xFkubw9No9

[Roe]

Let me know if you guys need any photos or anything of a revised Vibro-King ... I am also a big Gary Clark Jr. fan so I grabbed some info on one of his that a tech went through.

what is the reflected primary impedance of Clark's Vibro-king head that runs a 2x12 cab? does he run a 4ohms load from the 2 ohms secondary for a 8.4k reflected primary impedance?!

[rccolgan]

Let me know if you guys need any photos or anything of a revised Vibro-King ... I am also a big Gary Clark Jr. fan so I grabbed some info on one of his that a tech went through.

what is the reflected primary impedance of Clark's Vibro-king head that runs a 2x12 cab? does he run a 4ohms load from the 2 ohms secondary for a 8.4k reflected primary impedance?!

Yup! Exactly.

reflected primaries.png

[Roe]

Let me know if you guys need any photos or anything of a revised Vibro-King ... I am also a big Gary Clark Jr. fan so I grabbed some info on one of his that a tech went through.

what is the reflected primary impedance of Clark's Vibro-king head that runs a 2x12 cab? does he run a 4ohms load from the 2 ohms secondary for a 8.4k reflected primary impedance?!

Yup! Exactly.

reflected primaries.png

seems like a clear disimprovement! There were a few 4ohm vintage 30s allegedly, but he probably did not get those. Or he would need another output transformer

[rccolgan]

what is the reflected primary impedance of Clark's Vibro-king head that runs a 2x12 cab? does he run a 4ohms load from the 2 ohms secondary for a 8.4k reflected primary impedance?!

Yup! Exactly.

reflected primaries.png

seems like a clear disimprovement! There were a few 4ohm vintage 30s allegedly, but he probably did not get those. Or he would need another output transformer

lol it's all relative, I guess! I did get first-hand confirmation they are standard V30s and he "blows them all the time" ... or something to that effect.

[rccolgan]

Here's my Vibro King clone...

https://sluckeyamps.com/misc/Sluckey_Vibro_King.pdf

This is awesome BTW. Great FX loop idea coming out of the front too!

[Roe]

There is a related issue with the 5e7 which runs a 2.7ohm load from the 4 ohms secondary, lowering the intended 6k Z to 4k.

[rccolgan]

MM has some OT options.. the 4/8/16 is interesting...

https://www.mercurymagnetics.com/model/vibroking/

Might be less expensive to search on Facebook Marketplace for a used Vibroking! I picked mine up + 2/12 extension for $1200. They seem to go for around $1400 "normally" without the extension now. Not as fun as DIY....

[Roe]

MM has some OT options.. the 4/8/16 is interesting...

https://www.mercurymagnetics.com/model/vibroking/

Might be less expensive to search on Facebook Marketplace for a used Vibroking! I picked mine up + 2/12 extension for $1200. They seem to go for around $1400 "normally" without the extension now. Not as fun as DIY....

yes "4 kOhm primary — 4, 8 & 16 Ohm taps".

But the original 2.67ohms load connected to the 2 ohms secondary changes the 4k2 primary to 5k6 or so.

Adding the extension cab lower it to 3k36 or so.

Personally, I'd like an OT with 5k6 and 3k4 primaries and 4/8/16ohms secondaries.

For an 5e7, I'd like 4k primary and 4/8/16ohms secondaries.