5E3, first time build

[Arry]

Hi everyone. I recently built a tweed deluxe amplifier. This has been my first build ever, I’m fairly happy with the outcome but I’m having some trouble dialing in the tone I want.

I built the amp fairly stock, using mostly nos Allen Bradley resistors, Sozo caps, F&T and Sprague electrolytics. I used a .022 cap for the normal channel, a .047 for the bright, and a .01 cap for the phase inverter. Stock 25uf bypass caps. The only other mod I did to the circuit is the so called “Ampeg mod”, or “Paul C” mod. Transformers are the Hammond 291BEX P.T. and the Tube Amp Doctor tweed deluxe O.T. repro they sell.

My past experience with the 5E3 involves a Victoria 20112 that I owned and played for years, which I had later modified by Rondo at tweedeluxe.com to his studio series specs, and subsequently sold as it didn’t float my boat much.

I’ve played my amp for a couple weeks now and have found these issues with it.

1. The amp sounds a considerably brighter than I remembered; whereas the Victoria was dark and round, 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, it feels thin. Could it be that the Sozo caps have a certain brightness to their sound? Changing the tone cap from the stock .0047 to .0033 helped a bit but didn’t solve the issue fully.

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.

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?

I know there are many great amp builders on this forum, so I hope you can give me some suggestions! It was fun building it but I'm a beginner at this and I really don't have the knowledge to fine tune the amp to my liking : )

 

[Dostradamas]

Beautiful work
watching

 

[Powdog]

Nice work, but you’ve started out with a lot of mods already applied. Now you’re pedaling backwards trying to get your tone. I’d at least start by replacing the coupling caps with the original values. .02 and .05 in place of 0.1uF is gonna make it brighter. And unless tighter and brighter is what you’re going for, I’d also replace the big reservoir filter with a 22uF (like the other two).

I’ve found it’s always best to start with the stock schematic and modify one thing at a time. LOTS of people prefer a bone-stock 5E3 over a tweaked one.

 

[__HKGuns__]

It looks very clean and nice.

In addition to what Powdog said, what speaker are you using and what tube are you running in V1? It may not be the circuit.

 

[King Fan]

Nice tidy build. I'm sorry your sound is so far from your target. I agree with @Powdog -- it's easier to build stock, then mod. But then I notice you built this because a Vicky 20112 modified by Rondo didn't suit you? Many folks might have thought that would be a 'perfect' tweed Deluxe. The 5E3 is a distinctive circuit, and though hundreds of mods exist, that doesn't mean most of them can remove its peculiar charms and vices.

Working from stock, I ended up with a few of your values on my final version, so I have some thoughts about a sequence I might use to 'pedal backwards.'

Coupling caps: Your .022 and .047uF caps in normal and bright shouldn't cause *excess* brightness -- very common values. The .01 on the PI, by contrast, seems extreme -- if you mean the V2 plate. I'd go back to .1 there; if the amp's too dark, then you can go back down -- but maybe not that far. And I don't think the Sozos themselves are causing your 'too bright' sound.

What exactly is the Paul C mod on a 5E3? What were you hoping for there? I'd revert that to stock in any case.

What size are your filter caps? My final version ended up at 30/16/16 and my bass is tighter than stock but *not* excessive, just less flabby.

I have a 330-0-330 PT @120mA with stock 250Ω bias and 4.7K / 22K dropping resistors and get close to target voltages across the board, so I'm not blaming your PT, and I don't think your problem is your 138mA, either. Can you post a complete voltage table? I like this reference from Telenut62:

Do you have any specs for the TAD OT you used? Many companies sell '5E3 repro' OTs that don't match up nicely to original specs, and for sure that can change the sound.

The questions about which speaker and V1 tube are important, too. Good luck and hang in there.

 

[Arry]

Thank you guys for the nice words and the information provided. Since it was my first build I took all the time I needed to build it as nice as I could.

The reason I made the changes to the caps values is because those were the exact values I had changed in the Victoria amp too. In the stock form the Victoria 20112 were simply too bass heavy and congested. Going with the lower values made the Victoria more balanced and tighter in the bass. Then I found out about the Speed shop studio series amps and their recipe, so I sent the Victoria over, hoping they would turn it into the ultimate 5E3 but it didn't unfortunately... it changed so drastically that I ended up selling it. Different strokes for different folks I guess...

Anyway when I decided to build a deluxe myself it seemed counterproductive to start with the stock circuit, knowing that, at least in the Victoria amp, it sounded too bassy to me.

This is the “Paul C” mod:

As far as I know it’s supposed to smooth out the overdrive a bit, and make it less “fizzy” - “raspy”.

Tubes: I’m using nos Sylvanias: long plate 12ay7 (V1) and 12ax7 (V2), 6V6GTs and a 5V4GA. I actually haven’t tried another tube in V1, but I did try a duo of JJ6V6s and, if anything, they made the amp sound thinner.

Speakers: I’ve played the amp both through a Weber 12A125S (Jensen P12Q) and a Celestion V Type. The Celestion has more mids and it makes the amp sound slightly fuller, but it’s not a huge difference, and it does nothing to the highs, which still feel kind of thin and bright.

This is the T.A.D. output transformer: https://www.tubeampdoctor.com/en/output-transf.-for-fender-tweed-deluxe-5e3 It has 1839 on the bracket, don't know if that refers to a real Fender part number.

Filter caps: 30/22/22

Here is the voltage table. It looks like I have different voltages in the preamp compared to the original table...

 

[AxemanVR]

.
Sorry to be “that guy” but, you my friend are stuck in the “tone quest rabbit hole”…

Is it the circuit? The tubes? The transformers? The speaker? The cabinet? The guitar? The cable? The pick?

The only shortcut is to buy a dozen or more of each possible thing that might help to narrow things down and swap them out, one by one, until you find the perfect tone that you desire.

Buying dozens of capacitors and resistors is probably manageable, but speakers sure add up in a hurry, although I’m assuming either of those two things are most likely to make the most impact on changing the overall tone (for better or for worse).

Speaker options vary widely, so be prepared to test quite a few - if going that route.

Then there’s the all too subjective “personal preference” side of the equation. What you may dislike might sound great to me! So whatever advice I might offer may be the exact opposite of what you want.

Sorry to say this, but your project seems like it still has a ways to go before it’s completed to your satisfaction - and before you start thinking I’m just being an unhelpful jerk, believe me, I’ve been there…

…and sadly it can be a long journey that only you can complete.

Good Luck!







.

 

[mabinogeon]

.
Sorry to be “that guy” but, you my friend are stuck in the “tone quest rabbit hole”…

Is it the circuit? The tubes? The transformers? The speaker? The cabinet? The guitar? The cable The pick?

The only shortcut is to buy a dozen or more of each possible thing that might help to narrow things down and swap them out, one by one, until you find the perfect tone you desire.

Buying dozens of capacitors and resistors is probably manageable, but speakers sure add up in a hurry, although I’m assuming either of those two things are most likely to make the most impact on changing the overall tone (for better or for worse).

Speaker options vary widely, so be prepared to test quite a few - if going that route.

Then there’s the all too subjective “personal preference” side of the equation. What you may dislike might sound great to me! So whatever advice I might offer may be the exact opposite of what you want.

Sorry to say this, but your project seems like it still has a ways to go before it’s completed to your satisfaction…

Good Luck!


.

Yep! Leave it as is and put an EQ in front of it.

 

[__HKGuns__]

The speakers you are using shouldn't be an issue and using the AY in V1 is what I used as well and I don't have your issue in my amp, at least to my ears..... Interesting the plates of both pre-amp tubes are 40V lower than the Weber sheet, but that may be due to the circuit changes you've made. Someone with more experience than I will have to weigh in on that aspect. Its working, so it isn't fatal.

I'd probably back off the changes one by one and revert back to the original cirucit, testing in between changes. I think I'd start with the Paul C. mod if it were my amp.

 

[King Fan]

Thanks for the good details. If I'm thinking straight, you seem to be on safe ground with your PT, OT, filters, and the first two coupling caps. This doubles my interest in a bigger coupling cap on the PI and reverting the Paul C mod. If you find the overdrive raspy or ratty, a 470K resistor on the PI grid is a simple, effective cure. Details? This is one of the first mods on Rob's long list.

I'm gonna let smarter folks think about the voltages -- it is not rare for preamp voltages to be off some from the @Telenut62 values (for the record, folks, note they don't come from Weber, just wrote 'em on their layout for convenience).

Thanks for explaining your tone goals -- makes sense if you want to recreate your first 5E3. It's too bad (and a bit odd) that you find your recreated amp 'too bright' but with 'way too much bass' -- if I understand. Smart folks may be able to guess what could do that besides component values. What about triple checking the values and wiring of all three pots, visually and with an ohmmeter? What else could we look at, team?

 

[cobaltu]

in my case the bass is very tight but it’s overpowering

Here is my take on the 5e3: It has a lot of problems, and people address it in a number of ways. But, I think the core issue with the amp is - It is WAAAAAAAY over-EQed in the bass.

People often try to fix this by doing exactly what you did: upping the filter caps and even using a more robust power transformer. The problem is that this just unleashes the bass even more. Normally, the wimpy power supply in this amp would restrict the bass. The power transformer and filter caps would run outta current very quickly and the bass wouldn't reach it's full potential. Even the fact that these amps originally were equipped with P12r's - a rather trebley speaker - probably did a lot to help balance the amp's EQ.

The limited power supply also probably compressed more easily making the amp seem smoother. The large PT might also be the source of your spikey highs. The 5e3 has no NFB and can be rather "jumpy". VOX AC15/30s are also like this, but have much more robust power supplies and do have a tendency to be piercing.

I HATE to say this, but I think the PT is the main source of your problems. Most of the other mods - regarding coupling caps - that you made to the amp are sound and similar to my own 5e3. Even your speaker choices seem appropriate. This sucks, because the only way to find out is expensive and time consuming.

But before you resort to the expensive "nuclear option", here's what I would try:

• Take the filter caps down to 16uF, maybe leaving the first at 22uF. This will help restrain the bass and probably give you a more pleasing compression (tame the highs)

• Undo the Paul-c mod, returning to the stock arrangement. This mod changes the PI to a fixed bias which gives the PI more clean headroom. This mod I think works well in a Princeton Reverb, where a spanky, clean, snap is desirable, but in this amp I think if kinda goes against the whole "raison d'etre" of the 5e3.

• Go back to the 5y3 rectifier. I know you prefer the 5v4, but at 115% bias, you are killing those wonderful NOS 6v6s.

There are other things you can do, but for now, I would start here.

 

[2L man]

Measure V1 cathode resistor value! Perhaps it is closer to 1k? Combined cathode current comes high against anode currents using those voltages and standard values. Check anode resistors too? And when you start measure other resistors as well and then you can calculate currents measuring resistor voltage losses

(Edit: This paragraph might not have any walue now when you have used grid biased Cathodyne----Cathodyne bias look strange when there comes 3.3V between grid and cathode and if cathode resistor is 1,5k current comes 2.2mA which does not match 56k resistors voltage losses? Multimeter internal resistance might change tube biases? I admit I have never measured Cathodyne DC voltages and they might be just fine?)

V1 tube might just be "strong" and pull more current and then anode voltages come down? Cross swap with V2 and voltages should change?

Did you install Screen resistors for 6V6? Voltage on screen pins is 2V higher than B+2 capacitor voltage which should be other way?

 

[Arry]

.Sorry to say this, but your project seems like it still has a ways to go before it’s completed to your satisfaction - and before you start thinking I’m just being an unhelpful jerk, believe me, I’ve been there…

…and sadly it can be a long journey that only you can complete.

Good Luck!.

I know man, I can see the long and winding road ahead of me

Thanks for explaining your tone goals -- makes sense if you want to recreate your first 5E3. It's too bad (and a bit odd) that you find your recreated amp 'too bright' but with 'way too much bass' -- if I understand. Smart folks may be able to guess what could do that besides component values. What about triple checking the values and wiring of all three pots, visually and with an ohmmeter? What else could we look at, team?

Thank you for your suggestions! I'll check again.

Here is my take on the 5e3: It has a lot of problems, and people address it in a number of ways. But, I think the core issue with the amp is - It is WAAAAAAAY over-EQed in the bass.

People often try to fix this by doing exactly what you did: upping the filter caps and even using a more robust power transformer. The problem is that this just unleashes the bass even more. Normally, the wimpy power supply in this amp would restrict the bass. The power transformer and filter caps would run outta current very quickly and the bass wouldn't reach it's full potential. Even the fact that these amps originally were equipped with P12r's - a rather trebley speaker - probably did a lot to help balance the amp's EQ.

The limited power supply also probably compressed more easily making the amp seem smoother. The large PT might also be the source of your spikey highs. The 5e3 has no NFB and can be rather "jumpy". VOX AC15/30s are also like this, but have much more robust power supplies and do have a tendency to be piercing.

I HATE to say this, but I think the PT is the main source of your problems. Most of the other mods - regarding coupling caps - that you made to the amp are sound and similar to my own 5e3. Even your speaker choices seem appropriate. This sucks, because the only way to find out is expensive and time consuming.

But before you resort to the expensive "nuclear option", here's what I would try:

• Take the filter caps down to 16uF, maybe leaving the first at 22uF. This will help restrain the bass and probably give you a more pleasing compression (tame the highs)

• Undo the Paul-c mod, returning to the stock arrangement. This mod changes the PI to a fixed bias which gives the PI more clean headroom. This mod I think works well in a Princeton Reverb, where a spanky, clean, snap is desirable, but in this amp I think if kinda goes against the whole "raison d'etre" of the 5e3.

• Go back to the 5y3 rectifier. I know you prefer the 5v4, but at 115% bias, you are killing those wonderful NOS 6v6s.

There are other things you can do, but for now, I would start here.

I feel the power transformer could be responsible. In a way I almost wished all I had to do is get a smaller PT and be done! If I were to do that, what pt would you recommend @cobaltu ?
I'm really not looking forward to desoldering, pulling out and swapping components, soldering again... especially after I religiously installed all the components almost military style, bending the leads tightly so that they would stay in place without solder... my bad! Is there a recommended approach to swapping a component on the Fender style eyelet board?

Measure V1 cathode resistor value! Perhaps it is closer to 1k? Combined cathode current comes high against anode currents using those voltages and standard values. Check anode resistors too? And when you start measure other resistors as well and then you can calculate currents measuring resistor voltage losses

(Edit: This paragraph might not have any walue now when you have used grid biased Cathodyne----Cathodyne bias look strange when there comes 3.3V between grid and cathode and if cathode resistor is 1,5k current comes 2.2mA which does not match 56k resistors voltage losses? Multimeter internal resistance might change tube biases? I admit I have never measured Cathodyne DC voltages and they might be just fine?)

V1 tube might just be "strong" and pull more current and then anode voltages come down? Cross swap with V2 and voltages should change?

Did you install grid block resistors for 6V6? Voltage on screen pins is 2V higher than B+2 capacitor voltage which should be other way?

I wish I could understand all this! : ) I did measure the V1 cathode resistor and it reads around 915 ohms. Is that problematic? I checked the same resistor on my tweed Bassman and it also reads close to 1k.
I have 1.5k resistors on pin 5-6 of the 6V6s, not sure if those are the resistors you're referring to.

 

[2L man]

I wish I could understand all this! : ) I did measure the V1 cathode resistor and it reads around 915 ohms. Is that problematic? I checked the same resistor on my tweed Bassman and it also reads close to 1k.
I have 1.5k resistors on pin 5-6 of the 6V6s, not sure if those are the resistors you're referring to.

Grid block was wrong term and I edited it. Those 1,5k are Grid Block resistors.

I did mean Screen Resistors because it looked there was none when Screen voltage reading pin #4 was even higher than B+2.

It is common to use two 470 ohm screen resistors in 5E3 because Screen current come quite high when playing very loud and it stress tubes. Now without series resistors Screen voltage stay high when there is 16uF capacitor direct to Screens.

When 820 ohm cathode resistor is 915 ohm does not effect much but that make anode and cathode current calculations somewhat rational.

 

[Arry]

What about triple checking the values and wiring of all three pots, visually and with an ohmmeter?

I went through the whole amp this morning but it looks like it's wired correctly.
The only odd (perhaps) thing I discovered is that the capacitance of the first two caps seems to change according to how the volume is set: the 0.47 cap reads from 108nF (when the volume pot is on 0) to 49nf (when on 10). Is this ok?

 

[Michael Smith]

First off, nice job on your build!

If you've really installed the components "military style" you will need to remove all of the solder from the eyelets using a solder sucker and perhaps also some desoldering braid.

I'm certainly not an expert, but I didn't think you could accurately measure the value of a capacitor while it's in circuit. Perhaps someone else can provide some guidance here.

 

[SoK66]

Really nice work! I think you are on the right track with your .022 and .047sx in place of the .1s. You might try knocking back the other two .1s to .047 or even .022 and see what you think. I was having to run the tone control on my 5E3 clone (originally Mission Amps) almost maxed out. On a tip I started working the cap values back and IIRC I have .o22s in the front end and .047s in the tone cap and PI. Now I can dial it back and have some variability.

 

[Michael Smith]

A couple of years ago "Uncle Doug" posted a video regarding bias levels and the amp's tone and headroom. He did his testing on a Deluxe Reverb (fixed bias), but I would think the effect would be similar to a cathode biased amp. If interested I could find the video and post the link here (assuming the forum rules allow that).

 

[Snfoilhat]

Edit: didn’t read the first post closely enough

Great looking amp chassis!

 

[chas.wahl]

Really nice-looking build! But I have to agree with @cobaltu's analysis: too strong on the PT spec and filtering, it seems to me. The original 5E3 PT spec was 325-0-325 at somewhere between 70 and 90 mA load (depending on what apocryphal source one chooses to believe), and wall voltages almost everywhere have increased since the '50s. A PT supplying 330-0-330 at 135 mA has got to be pushing too hard (just my opinion); that's 50–60–70% more energy going in. And I think that the PaulC aka Ampeg mod is probably a false step.

Has anyone noticed that the plate voltages for the PI, 2nd stage preamp and V1 input stages seem to be rather low? Typical tweed circuits have ~150 V on the input stage plates, and for V2 something closer to the values on the first @Telenut62 layout posted by @King Fan above. Could that have anything to do with "thin" "out of focus, uninspiring"? Somehow an overabundance of voltage on the power tubes isn't making it upstream to the preamp, no? Comparing the two @Telenut62 layouts posted, the first has both lower voltage before the 2nd dropping resistor, and higher voltage after -- I'm looking at you, Mr 22k!

Or maybe Mr 22k is not to blame: here's an interesting thread contribution by @Bendyha (from 5 years ago) 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 . The whole thread is interesting, but his analysis particularly so.

@Bendyha also notes (he should know, I wouldn't) that "The Deluxe 5E3, and all the Princeton's (with the exception of the G2) all have approximately 250V phase inverter supply voltage." On that basis, the voltage drop in @Arry's circuit from power side on steroids to PI also seems excessive. @Bendyha ends with this nail in the coffin, that might also be a clue to why @Arry is having trouble with his 5E3 (blue emphasis added by me):

"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."

Caveat mutator. I'm as susceptible to this attraction as anyone, but it takes one to know one.