5E3, first time build

[King Fan]

... concerning the Fender tweed cathodyne PI and the fixed-bias mod notion, including the PaulC aka Ampeg mod, which he analyzes and characterizes as "often copied, but inadvisable": https://www.tdpri.com/threads/fender-cathodyne-phase-inverters.755580/post-7796029 .

Wow, super-sleuthing, @chas.wahl . Nice!!! I struggled to take that in at first, but I realize now this could be a double-good reason to take down the Paul C mod. I only suggested removing it out of instinct and caution and a distrust of that mod in other circuits, but if the OP does it and it helps, you totally get the prize for 'how and why' -- with the usual nod upwards to Bendyha watching over us.

 

[Arry]

"BUT.....the thing is, this unruly set-up will still work, nothing like intended to maybe, but work - it does. Instead of creating an efficient fixed-bias set-up, the tube will instead have to self-adjust with help of its equal loads on both cathode and anode, and swing itself into a new state of equilibrium. This requires it approximately doubling its previous pre-mod current draw, stressing the tube more, and dropping twice the previous voltage over each of the two 56K resistors (keeping them nice and warm). This way the tube pulls its cathode voltage up so as to be back within a few volts of the fixed grid voltage. So instead of freeing the cathodyne to work more effectually, it has instead become more limited in its potential output swing. Nonetheless, very strangely, some people who have tried it seem to be happy with the results."

Wow, excellent info @chas.wahl! I'll check out the full thread.
I'm also happy to try a different power transformer, but it's not easy to find a 5E3 replacement p.t. with similar specs to what you posted (325-0-325 @ 70-90 mA load): any advice on that?

 

[Arry]

Wow, super-sleuthing, @chas.wahl . Nice!!! I struggled to take that in at first, but I realize now this could be a double-good reason to take down the Paul C mod. I only suggested removing it out of instinct and caution and a distrust of that mod in other circuits, but if the OP does it and it helps, you totally get the prize for 'how and why' -- with the usual nod upwards to Bendyha watching over us.

By now I had pretty much given up and was ready take the amp to the local tech and have him inspect it, but I'll undo the "PaulC" mod and see how it behaves with the stock arrangement before I do that!

 

[Bendyha]

By now I had pretty much given up and was ready take the amp to the local tech and have him inspect it, but I'll undo the "PaulC" mod and see how it behaves with the stock arrangement before I do that!

I've nothing against using a fixed bias arrangement on the PI, but it needs to be done properly to obtain advantages from it.
Whether the iconic 5E3 circuit is a good candidate to exemplify those advantages, I have my doubts it would offer a sonic improvement. The "taken to the limits" 4 x 6V6 Kelley amps, which use the technique properly, probably does sound better set-up that way.
I wish you the best of luck, and plenty of enjoyment with your personal tone-quest. Don't give up yet, the build is looking good, and I'm sure you're not far away from your goal.

 

[King Fan]

Wow, excellent info @chas.wahl! I'll check out the full thread.
I'm also happy to try a different power transformer, but it's not easy to find a 5E3 replacement p.t. with similar specs to what you posted (325-0-325 @ 70-90 mA load): any advice on that?

I don’t think you need a new PT, speaking from personal experience. Your 138 mA at 330-0-330 isn’t very different from my 120mA at the same voltage, and mine works just fine. Let’s see what your voltages look like — and sound like — with 'Paul' out of there.

 

[chas.wahl]

Wow, excellent info @chas.wahl! I'll check out the full thread.
I'm also happy to try a different power transformer, but it's not easy to find a 5E3 replacement p.t. with similar specs to what you posted (325-0-325 @ 70-90 mA load): any advice on that?

I'm loath to see you spend more than you have to, for a satisfactory result, but I'm sticking with my story that 135 mA is over the top -- and in the event that turns out to be the case, here goes:

1. Hammond's 291AEX (only one letter off from the one you have) is a dual-primary/dual-HT-secondary model that has a 325-0-325 secondary at 100 mA, as well as 6.3 V @ 2.25 A and 5 V @ 3 A. I realize you're in Europe (apparently -- if you were in a 120 V country you could use the single-primary 290AX, which is otherwise equivalent). HawkUSA has the best prices on Hammond that I've found, but obviously they're across the ponds, and I don't know much about European sources.
Hammond keeps changing their 290A** transformers incrementally, somewhat irritatingly. It's hard to keep up -- same for their OTs. Over the years I've bought 3 of the 290A-somethings, none of which match the current models being offered:

EDIT: Whoops! I have to admit that the PT above (any of the 290A** ones!) has a smaller form factor than ones that are typically sold for the 5E3; it's a lay-down, but fits in a smaller hole, with smaller mounting hole spacings (2" x 2.5"), than what's on the 5E3 chassis (2.25" x 2.813")! So the only way to use one of these is to rotate the transformer 90º in plan, mount it to a plate to cover the original hole, and enlarge that hole somewhat in the minor dimension to clear the rotated transformer. Probably nobody but me would be interested in doing that. Sorry if that's a dead end.

I have to confess that I don't actually have a 5E3 (just an armchair observer with interest at present), though I plan to build one soon, and use the top one on my list for that -- going the other way from a lot of people's builds. The aforementioned @cobaltu is my mentor for this project.

2. He didn't say, but his 5E3 has a PT sourced from Mojotone that's 330-0-330; doesn't seem to be listed on their website; I don't know the mA on the HT secondary for certain, it might be as low as 75 mA. His 5E3 gets 320 V on the 6V6 plates, and he hasn't done any substitutions that would affect B+: NOS 5E3 rectifier and 6V6s. The supposed 5E3 transformer Mojotone do list is 355-0-355 (ridiculous!). Maybe a call to Mojotone would turn up the other alternative. Right now they don't even have the higher HT model anyway.

Thanks to @King Fan & @Bendyha for their expertise and viewpoints!

 

[King Fan]

@chas.wahl , are you thinking that the more current a PT is rated for, the more that drives up the voltages? IIRC, a 5E3 draws under 100mA -- their original PT may have been spec'd for 90? Can't recall. Admittedly, when the amp is working at max, the draw may drop the voltage a little, so you don't want a too-small PT, but amps aren't working at max most of the time. Once the amp can get the current it needs, it doesn't take more. The voltage may not be pulled down as it would on a nominal or marginal PT, but it doesn't go up further. So a 'big' PT increases voltages only by the amount a 'small' PT lets them get loaded downward, and I don't think that's all that far in a little old 5E3.

For that matter, I can't recall why you think his B+ is too high. Wouldn't his 380V would be pretty typical for a 5E3 on modern wall voltages. But NVM, if I were gonna drop my B+, I wouldn't start from mA....

 

[chas.wahl]

I don't remember seeing any curves for PT output V vs current draw, so I could be wrong, but my "belief" (perhaps ill-founded and wrong-headed) is that PTs are rated based on voltage at a given draw, as stated, and therefore if you don't draw as much current as spec, then the voltage is higher than spec. I don't know what typical voltage at the 6V6 plates "should be" on modern wall voltage, but my notion is that, to behave like a 5E3, with all its charms and warts, that voltage should probably be well south of 380. I could be totally wrong. My target is to build one that's somewhat "browner" than what people typically build, and see how that goes. If the PT I've mentioned, that undershoots the "typical" modern-day specs, doesn't work out, I have a plan B. (But see my edit to my post above, re: size!)

 

[Lowerleftcoast]

1. The amp sounds a considerably brighter than I remembered... ...this amp has a certain harshness in the treble frequencies that I don’t like. The normal channel is manageable, but the bright channel is really toppy and shrill... ...Changing the tone cap from the stock .0047 to .0033 helped a bit but didn’t solve the issue fully.

The .0047uF is not the *Bright Cap*. The 500pF is the tone cap to reduce to get rid of highs. (There are also other ways to reduce highs.)

I am curious about the speaker in the Victoria. As you know, speakers play a huge roll in perceived highs and lows.

2. The amp sounds fuller and a bit more balanced if I use a 5V4 rectifier in place of the 5Y3: highs get stronger and more musical, less thin. But this also raises the plate voltage to about 380-385vdc, and according to my calculations I get a 115% total dissipation (cathode resistor is 270ohm - but actually measures 262). Why does it sound better with the higher voltage? With the 5Y3GT I get around 350vdc at the plates but the amps sounds out of focus, uninspiring.

It doesn't surprise me the amp sounds better when the bias is at 115%MPD. As a general rule a cathode biased amp will sound *better* when past 100%MPD. I am concerned when you use the 5Y3 that the bias is not high enough. I would like to know the bias numbers with the 5Y3.
BTW, it is said, an amp usually sounds best just before it dies from over current.

3. It has the strongest bass of any amp I’ve had. I know 5E3 are famous for the flabby bass response: in my case the bass is very tight but it’s overpowering. The best way I can describe it is like I have a gain boost on the low A and E string of the guitar, the low frequencies are really overwhelming.
Could this be related to the fact that I’m using a larger P.T, with a higher current-lower voltage secondary (330-0-330 @ 138 mA)? Or maybe it is the O.T. that is producing a lot of bass frequencies?

It is a bassy design. Again, the speaker can be emphasizing the bottom. I would think the Weber 12A125S would be OK for this circuit.

I am going to disagree with the other Shock Brothers, I don't think the high current capability of the PT has anything to do with a 5E3. The 5E3 current draw does not increase/decrease like it does in a fixed bias circuit so as long as it has enough current, the 5E3 will be happy. The 5E3 really doesn't count on PT sag.
The concern of a high current capable PT is that the voltage may not drop into the *expected voltage range*. Your B+ looks to be in the ballpark. (One of the desirable PTs for a 5E3 was a Classictone 325-0-325 rated at 120mA. The B+ came in about 370v.)

I'll undo the "PaulC" mod and see how it behaves with the stock arrangement

I think undoing this mod is where I would start. The bias on this PI can be implemented but it has to be dialed in. The original bias circuit is self biasing and not as finicky. As long as the 56k resistors are fairly closely matched, the PI works fine. Please post your voltages once this mod has been reversed.

I would propose a global negative feedback circuit to do what you are expecting of the *PaulC* mod. I put the NFB on a switch.
I would also install 470R 6V6 screen resistors like so many of the later Fender amps have.

We will talk about the highs and lows later.

 

[King Fan]

I am going to disagree with the other Shock Brothers, I don't think the high current capability of the PT has anything to do with a 5E3.

Thanks, I'm glad you agree with this Shock Brother. I was starting to question my sanity, or at least my understanding.

 

[chas.wahl]

I apologize in advance for the length of this; I'm not trying to be objectionably perseverative, just comprehensive, and I think that this is an important and interesting topic concerning the recreation of vintage amp designs.

@chas.wahl , are you thinking that the more current a PT is rated for, the more that drives up the voltages?

Yes, I believe so.

Admittedly, when the amp is working at max, the draw may drop the voltage a little, so you don't want a too-small PT, but amps aren't working at max most of the time. Once the amp can get the current it needs, it doesn't take more. The voltage may not be pulled down as it would on a nominal or marginal PT, but it doesn't go up further.

My concern is that, when "underloaded", a PT may be providing higher voltage than whatever vintage amp circuit one is trying to emulate.

I am going to disagree with the other Shock Brothers, I don't think the high current capability of the PT has anything to do with a 5E3. The 5E3 current draw does not increase/decrease like it does in a fixed bias circuit so as long as it has enough current, the 5E3 will be happy. The 5E3 really doesn't count on PT sag.

Hmm -- this is a point of contention against other views I've seen expressed previously in such discussion. For instance, in this thread (2018, p. 2):

The classic tweed deluxe PT spec was:

HT: 325-0-325VAC @ 80mA (this current rating is on the verge of minimum adequacy, but contributes to the saggy charm of the original. 90 or 100mA would be more 'secure')
Heater: 6.3-0VAC @ 2A
Rectifier: 5-0VAV @2A

In a 5E3, this should produce a B+ around 350VDC with the stock circuit.

I don't know where @tubeswell got that specific information, but it's something he's written about at least a couple times, like here, post #11.
And from the same thread where I've quoted @tubeswell:

The higher the current is rated at, the less '5E3' it will be. That can be a good thing, but it just depends on if you are intent on a clone or something more to your liking.

Another great example is the Princeton Reverb. The PT is barely adequate, but is what makes a Princton Reverb a Princeton Reverb. Drop a 120mA transformer in there and it is a different amp for sure.

Without trying to be snarky, I'll note that at least a couple other people "liked" each of those. Obviously, I'm inclined to these opinions as well.

Thanks, I'm glad you agree with this Shock Brother. I was starting to question my sanity, or at least my understanding.

My reasoning about this (unproven by experiment, admittedly) is that it's well known a PT has a higher voltage when measured unloaded, and a rated voltage at a given load. I'm pretty sure that between these is not a quantum state change, but one where voltage decreases with increasing load (until one reaches the point where overheating fuses a winding, and the smoke starts -- or do I have the sequence of the last two backwards?) So, using the present example, I expect that, if trying to recreate a 5E3 circuit in some fashion, using a PT whose voltage is determined at a HT current more than 150% of what the original circuit's PT was rated for (135/80) is bound to result in a higher B+ than would have been measured in the original. And we haven't even invoked the issue of present-day wall voltages being, to some extent or other, higher than they were in the '50s.

I'm happy to be corrected (with a reasonable explanation of why), if that's untrue.

I have tried to find confirmation, independent of @tubeswell's recollection, of what the specs for the Triad 6452 PT was, in vain; with one exception: this posting by "FYL" preceding @tubeswell's in the same EL34World (Hoffman Amps) thread I've referenced:

"The 5E3 - and other Fender amps from the same period - used a Triad 6452 PT. At 110V/60Hz mains, B+ was 380-0-380V unloaded with a highish 230R secondary DCR, leading to app. 350V loaded at C1 with a real 5Y3GT.

"Measured unloaded & loaded voltages + specs of an actual '57 vintage 6452:
B+: 380-0-380V 230R, 100mA => 358VDC
H: 7V 0R45, 3A => 6V4
V: 5V5 0R26, 2A => 5V

"Loaded voltages measured using a typical all-RCA period correct tube set (12AY7, 12AX7, 2x 6V6GT, 5Y3GT) and a vintage board fitted with recent elcos. B+ could be slightly lower with lossier caps, but still in the 350V range."

Note that the 380-0-380 (like the 7V and 5V5 filament voltages) are unloaded, and those following the => are loaded, and that the testing was apparently done at 110 V. Why the 230R secondary DCR is "highish" is not explained -- maybe because wire gauge was thinner, or winding longer, than expected by the tester?

The same 6452 PT seems to have been used through several iterations of the 5*3, early ones being stand-up configuration, but numbered the same, sometimes labeled 6452-E and sometimes 6452-I.

In going down this rabbit hole, I've discovered that I'm not the only person who's considered or built 5E3's using the Hammond 290A** series PT (with smaller form factor than "the usual suspects" available, as I posted in an edit above). Both this thread where I've quoted FYL and @tubeswell and this one (also on EL34World) have discussion of doing so, and also additional support for the "you don't want the PT rated current to be too high" point of view.

Finally (if anyone's gotten this far) I'll close with Steve Luckey (sluckey), a mainstay & stalwart of EL34World, as a secondary source, whose 5E3 project files indicate a PT 330-0-330, with a B+ at first filter cap of 345. His build of a "straight-up" 5E3 shows a laydown PT without an end bell within the chassis, which I haven't seen as a production item; EDIT: it is almost certainly a Mercury Magnetics; as Steve Luckey mentions in another thread on this topic (post #2), his 5E3 ("stock", not his "Tweed Deluxe Reverb") has "iron from a Deluxe Reverb Reissue", and when I go looking for DRRI youtubes, I find similar PTs with no end bell on the interior, and they're marked with MM's Chatsworth CA address on the exterior. I'll add that, based on what I've seen perusing their site, MM's published voltages for PTs seem to be "unloaded" (without mentioning a HT current capability), unlike, say, Hammond's stated specs.

I can't recall why you think his B+ is too high. Wouldn't his 380V would be pretty typical for a 5E3 on modern wall voltages. But NVM, if I were gonna drop my B+, I wouldn't start from mA....

While it might be "typical" I would not say it's something to aim at. There are a couple reasons why.
A) Lots of people complain about their B+ being too high on this forum, when they've got a vintage schematic in front of them and their result is unexpected or even "shocking" -- and there's a lot of discussion here devoted to talking them out of that tree, and counseling people to be careful about what PT they choose. In the case of the 5E3, there's no "Ur" voltages information, just what this or that person says is "standard" for a 5E3. So it's a matter of belief. The closest I can find to a believable source is FYL's measurements, resulting in B+ "in the 350 range".
B) Sluckey built a modern one at B+ 345. @cobaltu has one operating at about B+ 320, that really pleases him. They both have nominal 330-0-330 PTs, dunno what the mA ratings of those are, but somehow they're getting, and apparently are satisfied by, significantly lower B+.

I'm sticking with "Less . . . is . . . more"!

EDIT: I can no longer edit my post #26 above, where I gave 2 examples of PTs with lower HT output -- here's another:
3. Mercury Magnetics seems to have a whole lineup of PTs at varying HT levels for the Tweed Deluxe and Deluxe Reverb amps; they also do both single 120 V primary and dual-primary models. Unfortunately, as I've mentioned above, their HT "spec" is typically unloaded, not at any specified mA rating; so if interested in one of these (they run about USD $200 currently) it would be best to call or email them for more information.

 

[tubeswell]

For a 5E3, I'd stick with HT = 325-0-325VAC @ 80-90mA. The higher mA you go, the 'cleaner' and less 'tweed-like' it gets. YMMV

 

[chas.wahl]

Thanks @tubeswell. Another thing I neglected to mention: @jsnwhite619 had posted awhile back notice of this YouTube "teardown" of an original Triad 6452 PT (it was a "stand-up" one, probably from an early version of the 5*3 series), which I had high hopes for; however the guy "dissected" it not too politely, and didn't count turns, measure wire gauges, record which wires were connected to which amp functions. So, useless on the level of how one would recreate it.

 

[King Fan]

Heh, yes, a small enough PT will give you PT sag (subtle, nice) and slightly lower voltages -- if it's small enough to be loaded down. And those small tweeds had 70-90mA PTs and low-ish voltages. I can lower my 5E3's voltages with my bucking transformer. So I'll bet (on this and any topic) that @tubeswell is right -- a small PT will sound less clean and more tweed. I'm just thinking our OP with his too bright, too bass-y 5E3 isn't suffering from a lack of tweed. Would sag and 'brown' sound cure his ills? I guess it might. But would I put it high on my $/likelihood scale? No.

 

[gabasa]

There have been a lot of successful 5E3 builds with that Hammond PT so I personally wouldn't change it. I do agree with the consensus of reverting it to the stock circuit though.

A big lesson I've learned over the past few years is that a build is only as good as the output transformer, and there's no getting around that. You'll never be able to faithfully replicate the sound of a vintage amp if you don't have a faithful recreation of its output transformer. This is much harder than it seems, because most today are wound to the same specs as the original ones, but sound nothing like the originals. Soursound's 1839 would transform your amp into something very special, once the amp is stock. Figure out what your favorite speaker is after that point (like a 12A100T or 12A125A) and enjoy it for decades after the speaker breaks in properly. I feel that anything beyond this is overcomplicating things for the original poster, unnecessarily.

Screen resistors are always a good thing.

A popular, proven mod is The Edge Deluxe amp mods ... he's toured with them and still loves them. However, with a Soursound SST1839 OT and the correct Weber, you probably wouldn't care to modify it afterwards.

This is all just my opinion ... not trying to override anything anyone previously said. That was a beautiful build ... great layout and workmanship!!!

 

[gabasa]

AFAIK, the last tweed Deluxe with a B+ spec was the 5C3 at 360VDC. Your amp is within 3% of that spec with a 5Y3, so I’d consider that quite close.

 

[Lowerleftcoast]

I think that this is an important and interesting topic concerning the recreation of vintage amp designs.

Hmm -- this is a point of contention against other views I've seen expressed previously in such discussion. For instance, in this thread (2018, p. 2):

The classic tweed deluxe PT spec was:

HT: 325-0-325VAC @ 80mA (this current rating is on the verge of minimum adequacy, but contributes to the saggy charm of the original. 90 or 100mA would be more 'secure')
Heater: 6.3-0VAC @ 2A
Rectifier: 5-0VAV @2A

In a 5E3, this should produce a B+ around 350VDC with the stock circuit.

.
According to my off-the-cuff memory the original 5E3 PT was rated (off 110VAC mains supply??) at:

325-0-325VAC @ "70mA" (*)
6.3VAC @ 2A (just enough for 2 x 6V6, 2 x 12A_7, and a 0.5A bulb)
5VAC @ 2A

and it was the same as the BFPR PT** (and OT). But don't ask me where I 'remembered' this from.

* Hmmm... I guess this assumes that the 6V6s would be conducting less than the full 360 deg cycle. I think that the rating on the PT was conservative. The fact that it was designed with a 110VAC mains could explain why FYL's measured example would be quite a bit higher.

There is a lot to unpack here. Let's dispel the 110 wall voltage. Back in the day, I (we) referred to the wall voltage as 110v (I still say 110v quite often. After all, it is half the 220v the dryer uses right? Ha!) I remember (in the early 60's) my young self questioning my father why the wall measures 117v when it *should be* 110v. Now I will not dispute some places across the country would *measure* 110v. I will dispute that the power Fender designed for was 110v. (This goes for their PT suppliers as well.) Have a look at the Bassman 5F6A I-EG and Twin 5F8 F-EG schematics. These amplifiers are contemporaries of the 5E3. The schematics show supply voltage of 117v. (Back in the day I am pretty sure I was on the same power grid as Fullerton Fender. I lived near by.) Now that you have seen the schematics, I hope we can agree 110v was not *the carved in stone vintage supply voltage* we read on the internet today. And, before anyone balks, yes even then, wall voltage varied throughout the day.

I believe tubeswell's *off-the-cuff* memory in that post #11 was a memory of the Champ. The Champ, not the 5E3, used the same PT as the BFPR. That 70mA PT also has smaller mounting dimensions than the 5E3. I do like his comment about all of the PT companies varied recommendations for 5E3 PTs, "Fraught with different opinions init?".

Concerning the difference of opinion about 5E3 sag...
Imo, the 5E3 may sound like it has sag but I think Blencowe's description, "Cathode bias often lends a natural compression or 'squishiness' to the sound, due to the increase in bias voltage when one valve enters Class B conditions...", and "extra second harmonic distortion", is more accurate. It also might get some added compression from the Cathodyne PI with the 56k resistors. Also, the 5E3 responds more like a single ended amp. Aiken makes the comment of cathode bias, "you might still be able to get away with biasing at max dissipation because of the large bias shift at full power". This seems to describe the 5E3. It seems to fit his description because it readily will bias at over 100%MPD. *Sag* should come from taxing the PT and/or from the 5Y3. Different builds of the 5E3 do not demonstrate *sag* conditions. It seems as long as the B+ voltages are in a certain range the 5E3 sounds like a 5E3. A solid state rectifier vs a 5Y3 makes little difference and I hold the current capability of the PT makes little difference. Get the B+ voltages right and it will do the 5E3 squishy growl thing. Edit: the signal voltage also has to be able to get high enough.

 

[2L man]

5E3 Power Supply should sag when outputting high power! If playing clean / low power it is not important.

The PS is more than Power Transformer! Rectifier tube, voltage dropper resistors and filter capacitors belong to PS.

I have measure even 60mA RMS Screen current for each 6V6 using voltage loss measure over 470 ohm screen resistors but current drop soon when PS sags. I did not measure what the anode current was the same time

Obviously there comes interaction because screen voltage has almost direct effect to anode current potential?

When output transformer saturates and current thru tubes increase the PS should sag as well. If not there is bigger danger to "cook" the OT.

 

[chas.wahl]

I will dispute that the power Fender designed for was 110v.

It's funny, then, that 110 V is what's listed on their tube charts. Somebody made that decision. I fully realize that in the US, increases in line voltage from 110 upwards were well in progress in the 1950s; not everywhere at once, but inexorably. So that's just a huge gray area.

There's also a big disjunction, generally, between what people claim Leo Fender's object in designing tube amps ("clean") was, and the way that equipment got used (distortion became not just a by-product of electronic amplified music production, but something sought after as part of the art form). So we have the convergence of rising power levels (in this country) and a new sound that was, at least partly, fomented by that. Against that background, what is "the 5E3 sound" that everyone's looking for, or is that a bunch of different things?

*Sag* should come from taxing the PT and/or from the 5Y3. Different builds of the 5E3 do not demonstrate *sag* conditions. It seems as long as the B+ voltages are in a certain range the 5E3 sounds like a 5E3. A solid state rectifier vs a 5Y3 makes little difference and I hold the current capability of the PT makes little difference. Get the B+ voltages right and it will do the 5E3 squishy growl thing. Edit: the signal voltage also has to be able to get high enough.

I think that the use of the "sag" term is probably a bad approach -- for one thing its meaning in usage is highly variable. Let me put it this way: I think that there are several reputable sources (some mentioned above) who seem to feel strongly that the "essence" of a "5E3" sound is having a less-than-robust power supply, and that if you equip one with a "stiffer" one, you have a different amp. Whether the amp in question here is suffering from that syndrome remains to be seen; I'm interested to hear more from @Arry when he's made some change(s) that improve his experience with his amp.

 

[Wyatt]

The Vicky 20112 is a stock 5E3 circuit. If you liked and used the stock Vicky for years, but didn't like it after modded, I would say the first step is to unmod the build and take the circuit back to stock— the filter cap values, the PI, the Bright channel, everything. The 5E3 is a classic for a reason, but not everyone's cup of tea. The mods exist to change the amp for people who find out 5E3 don't suit them. Get it stock, then tailor to taste, one mod at a time.

Beautiful work, BTW.