Tweed Caps

[Fredaxis]

Hello, I am ready to try defarting my 5e3.
All of the orange caps inside are Sprague 715, Should I keep going the same with my mod or would it benefit to stick the same Mallory's as in a TW or other caps?

Any thoughts??

Thanks in advance,

Fred.

[Firestorm]

FWIW, Gerald Weber says that he thinks that Mallory 150s sound the most like the Astron caps Fender used in the day. I wouldn't know -- I've never seen an Astron that wasn't leaking its ass off!
But the Mallory 150s do have the advantage of being physically smaller than ODs so you have more latitude in placement and orientation. That .02 cap coupling the output of the second gain stage is perilously close to the input jacks (and in phase with them), so moving that cap around is one of the standard fixes for strange behavior.

[slajeune]

I'm not sure that changing the capacitor from what's in there to Orange drops or mallory's will help. You need to change the values.

Looking at the 5E3 schematic:

http://www.ampwares.com/ffg/schem/deluxe_5e3_schem.gif

I would try the following:

Lower both cathode bypass caps to 10 or 5uF (the 25-25 caps accross the 820 ohm and the 1500 ohm cathode resistor).

This should get you going in the direction that you are looking for.

Bonjour du Québec!

Stephane.

[Fredaxis]

Bonjour Stéph !!!
C'pas seulement un changement de marque,là, pantoute!

I plan on trying to reduce my cathode bypass caps and to try 0.022 µF caps on the PI, so it is not only a brand change.
As I have to buy the caps anyway I thought it may be a good opportunity to "upgrade".
May be to PVC Mallorys, some PIO or whatever.....

I used to work a lot around Chicoutimi, Tadoussac, Ste Hyacinthe, Québec/St Romuald, Berthierville and Granby last year, may come back as soon as the sub-prime effect is over..

Fred.

[slajeune]

Bonjour Fred!

Ca fait toujour plaisir de pouvoir echanger un peu en francais sur des forums

Ok, I wasn't aware that you were going to change the values. Here is what I am aware of:

- Mallory 150 seem to be what a lot of people working on Fender amps go for.
- As for the PIO, they will definately make the sound more mellow. If you're amp is already a bit muddy, it might not be the way to go. Having said that, my latest build has one PIO, the cap right before the cathodyne phase splitter. I would have used them in other places but sadly, I didn't have the required values. There are a few russian / ukranian sellers on ebay selling them. Very nice caps and a great price!

BTW, here is a link to my hybrid 5E3 with a few sound clips:

http://www.sophtamps.ca/mambo/index.php ... &Itemid=56

As you can see, I am using orange drops, mallory's and a PIO. Both bypass are 6.8uF and I don't find the amp farty at all!

Hope this helps!
Cheers,
Stephane.

[cobalt]

Hello,

What is the value of the cap between the 12AX7 sections? Is that also
.1mF/400V? It does not seem to be labeled.


cobalt

[slajeune]

Hi cobalt,

looking at the schematic, which cap are you talking about?

Cheers,
Stephane.

[Tubetwang]

here's what works for me...

.01 pin # 1 on 12AY7
.022 pin # 6 on 12AY7
.047 pin # 6 on 12AX7
.047 pin # 8 on 12AX7

if you want less bass change the pre-amp bypass caps to 4.7 from 22uf

[Structo]

Hello,

What is the value of the cap between the 12AX7 sections? Is that also
.1mF/400V? It does not seem to be labeled.


cobalt

Looks like 100pf will work.

[Firestorm]

Hello,

What is the value of the cap between the 12AX7 sections? Is that also
.1mF/400V? It does not seem to be labeled.


cobalt

Looks like 100pf will work.

Actually, it's .02uF. The schematic is unlabled, but the layout is.

[Icetech]

i will say this... i didnt believe that changing brands of caps would matter, but i did it after a guru told me too.. no values just get rid of the mallory 150's... and WOW... the difference was amazing in the amp, i will never use 150's again (unless it was called for that type of tone), switching to 615's i think it was, made it warmer and nicer all around...

[muchxs]

I seem to be alone with this opinion but... the same concepts that apply to every hi-fi amp ever built apply to the tweed Deluxe.

You won't get hi-fi with a wimpy power supply, in particular lack of current makes farty bass. It's a direct relationship. Take a look at any quality tube like an old Dynaco, Marantz or McIntosh, if there's one thing they have in common it's that they have a power supply like an arc welder.

You can screw around swapping coupling caps, swapping cathode caps or wiring in various hokey mods and you'll be wasting your time IMHO.

Here's my fix: Swap the 5Y3 for a 5AR4. If you're using the correct transformer the secondaries should be 260-0-260 or 275-0-275, the sweet spot for the plate voltage is around 310 volts but anything less than 350 volts is just fine. You can go higher but you'll lose some of the tweed amp character. Your filter caps should be 40 @ 450, 22 @ 450 and 22 @ 450. If you intend to go back to the 5Y3 at some point use three 22 @ 450 caps in the power supply, 40 @ 450 is too big for a 5Y3 rectifier.

Once you use a 5AR4 you'll never go back. Use a 5U4G if you must, I like the controlled warmup of the 5AR4.

The tweed Deluxe was designed to use a 12AY7 for V1. The amp will clean up by turning down your guitar volume like it should, the clean tones are fat, crisp and really very nice. Cranked it has a great tweed distortion tone even with the "low gain" 12AY7. A lot of builders will use a 12AX7, 12AT7 or anything but a 12AY7 for V1. That's a quick way to convert the amp into a whoopie cushion.

If you want a modern high gain distortion tone build a Trainwreck or a Dumble. Use the right tool for the job, you'll be happier in the long run.

[Firestorm]

I think muchxs made some pretty good suggestions. The wrinkle is that a good sounding 5AR4 will cost you $150. I have A/B'ed Blackburn Mullards against US-made GEs, NOS Japanese, Sovtek and JJ. In a LOT of amps (not all, but a lot) the difference a real Mullard makes is huge. Not quite night and day, but definitely like The Wizard of Oz when the film changes from b/w to color.
A nifty, good-sounding alternative that will get you more juice than the 5Y3 (175mA) is the 5V4GA. Indirectly heated like a 5AR4 (slow warmup, lower internal resistance), these were pretty much never used in MI amps (except for Matchless) so the price has not been driven through the roof. NOS RCAs and Sylvanias -- $20!
This tube will take 40uF on the first input cap -- don't be misled by some later data sheets that show "typical" operation with 10uF.
Incidentally, the ratings for most rectifier tubes assume an "effective plate supply resistance" of 100 ohms. A lot of PTs actually have more than that so you can use higher values of capacitance.
To calculate your effective plate supply resistance, measure the resistance (in ohms) of the primary (R1); measure the resistance from the secondary center tap to one end of the secondary winding (R2), find the ratio of the primary voltage to one-half the secondary voltage (with no load) -- for example if it's 117VAC to 260VAC the ratio is 2.2. We'll call that X. Your effective plate supply resistance is R2 + (X[squared] * R1).