#171436  by perljam
 
Hey now...

I'm thinking of taking a '67 Blackface Twin and putting it into a head to make it easier to take with me. Two questions...

- Anyone have any clever ideas on a vertical case design that I could make? I was thinking of something like this: https://louiselectricamps.com/product/c ... -amp-head/ but wondering if there are other ideas.

- My amp guy is going through it now to make sure it's to spec, has good caps, etc. It had been modded before. Are there any key Garcia mods I might want to consider? Hard to find the latest documentation...
 #171437  by Jon S.
 
As for potential TR mods, if you do some internet word searches, you'll find comments like these in the public domain that may assist you. Note that I have no relationship or affiliation with any of the cited sources for the info. that follows. I'm merely letting you know who I saw posted the info. in case you want to take that into account in determining its usefulness to you:

* I just saw on a respected sources website that Jerry's Twin had .022's in the tonestack instead of the normal .1 and .047. (Imagined Days)

* .022s in the mids will keep more mids around than some of the other higher value capacitors commonly used in fender amps, and .022 in the bass will cause the bass frequencies to drop off at a higher value and lose a lot more overall bass than the .1. So, theoretically, .022s seem to make sense for jerry (more bass cut and less mid scoop) (Stevo123)

* It is by no means a secret mod, others have done it. using the duncan tonestack calculator, and the known jerry twin settings, show a pretty identical curve between the stock values and the .022uFs. the difference being the sharper bass rolloff with the .022uF's. (Mike Wald)

* Just got my twin back from the tech with all the healy mods done and played a farm gig over the weekend. YOW! Talk about clean power and clear highs and lows. (JB Arnold)

* Let me suggest a place to start: First, in addition to changing all of the caps, you will want to change all of the plate resistors for non-inductive metal film versions. Also change all of the cathode resistors and use tantalum capacitors for the bypass caps (I use military grade axial lead versions). This, especially for steel, will greatly improve the high frequencies yielding the pure and clearer bell like tones. (JB Arnold claiming to be quoting Healy)

* I've done most of the mod that JB quoted except for the non-inductive metal film plate resistors. That's next. The other mods were amazing. I've never heard a Twin so open and sweet and clear and hi-fi before. The steel just sings thru it. (Brad Sarno)

* Maybe you’ve moved on from your Silverface twin project, but I still want to chime in. I’ve got the same amp (late 73 twin reverb with all rca tubes. Mine doesn’t seem to have the power tube suppression caps either) and I’ve done a lot of the preamp mods mentioned in this forum and elsewhere about how to achieve Jerry tone. I’ll give you a little rundown of what I’ve done, and encourage you to dive in:

- changed the tone stack .022,.022, and 250pf - Sprague 225p and silver mica

- dale metal film plate resistors, RN series

- Sprague tantalum 150 series cathode bypass caps, 22uf

- black-faced the phase inverter and bias pot with dale metal film resistors, xicon metalized polypropylene caps - I like these in the phase inverter over the orange drops: responsive, 3-dimensional and textured

- changed the phase inverter input cap to .oo27 Sprague 225p - fattened up the tone just enough

- disassembled the master volume circuit, and disengaged the tremolo

- after lifting the wire to the Tremolo pot, I changed the cap on the right of the phase inverter from .1 to .047 (Sprague 715p) this tightened up the bottom end in a necessary way - I don’t see too many people talking about this but it seems important to my ears

- I changed out a few capacitors here and there to 225p orange. Drops

- AND just today I swapped out the reverb driver resistor on v4 from 850 ohm to 2200k metal film and found the sonic edge I’d been looking for. It added a bit of gain and breakup overall and a quality to the reverb that is just killer. I feel I’m almost there - think early spring ‘78 (Pointclear)
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 #171439  by Chocol8
 
While it is tempting to make it as small and light as possible, you want some space between the reverb tank and the power transformer. Also orient the tank so the output side is furthest from the PT as it picks up interference more than the input side.
 #171441  by strumminsix
 
Unpopular opinion: you'd save yourself some time and hassle and start with a Dual Showman Reverb.
 #171442  by Chocol8
 
strumminsix wrote: Tue Aug 17, 2021 7:25 am Unpopular opinion: you'd save yourself some time and hassle and start with a Dual Showman Reverb.
Yes, the silver face Dual Showman Reverb is essentially a silver face Twin Reverb in a head. The other Showman and Dual Showman amps are different enough that I wouldn’t want one for a Jerry amp.

The trick is finding a good Dual Showman Reverb, or one worthy of fixing up at a reasonable price. I see far more Twins locally, and plenty have been beat up enough that I wouldn’t feel bad building a new enclosure.
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 #171443  by Jon S.
 
strumminsix wrote: Tue Aug 17, 2021 7:25 am Unpopular opinion: you'd save yourself some time and hassle and start with a Dual Showman Reverb.
Nothing unpopular here! And you can even add a pair of 8" speakers to the head, if you want, for a killer "sleuth" rig.
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 #171447  by Smolder
 
I’ve had a couple of twin (and a super) reverb mounted in head cabs. The big cab isn’t really necessary… just shift the reverb tank as far from the power transformer as you can get it.

Jon’s list of mods is spot on. I’ve done the standard mods (with the exception of the power tube bypass) on pretty much every bf or sf fender I’ve owned.
 #171448  by perljam
 
Thanks for the input. I'll take this all under advisement. I like the idea of the Showman Reverb but the Twin is already in my garage...
 #171452  by strumminsix
 
Always glad to help! My experience for a few pros on the DSR:
- as it's been a solo head, likely better maintained
- many older twins are much more beat up and abused since they've been housed with heavy speakers and moved like heavy luggage, LOL!

But yeah, modding what you own is a great. But the expense and cost of rehousing and modding etc... sometimes gets crazy.

But there's another thought... Instead of crazy full GD... you could rehouse the Twin in an aftermarket DSR head :)
 #171462  by Smolder
 
Jon S. wrote: Tue Aug 17, 2021 8:48 am
strumminsix wrote: Tue Aug 17, 2021 7:25 am Unpopular opinion: you'd save yourself some time and hassle and start with a Dual Showman Reverb.
Nothing unpopular here! And you can even add a pair of 8" speakers to the head, if you want, for a killer "sleuth" rig.
That’s suppose to be top secret! ; )
Jon S. liked this
 #172684  by Darkstar860
 
I had a Twin Head for about 15 years, def was nice to split the weight up. That was my main rig until about 8 months ago. Twin Head into custom 2x12 with E-120s. Now im using a SMS CTP with a ART SLA-1 power amp which is even lighter. But anywhoo, im shocked you dont see more people take the amp out of their twin and put it into a head cab.

-Walt B