Express Low End

eazilyled · Post by **eazilyled** » Thu Dec 06, 2012 8:00 am

You could always temporarily alligator clip the extra cap you have onto the existing cap to see if you like it.

Not sure if the use of a ceramic was significant or not. Could be that KF was aiming for a certain sound, or perhaps they were easy to come by and he had them spare?

You're not the first person to have found that the extra resistors made a difference for the better. In theory I think that these would just suppress ultra high frequencies and perhaps oscillation. What's going on there?

Post by **Colossal** » Thu Dec 06, 2012 9:42 pm

As a footnote on this...I have two single cut/LP style guitars. Both have single piece mahogany bodies and necks, rosewood fingerboards. One with a quilt top, the other a flame. Both have very PAFy sounding humbuckers. The flame top is considerably heavier with a much more trebly sound. The pickups sound much more trebly as well compared to the other other guitar. The other guitar is very warm (it might be a weight relieved slab or just a light piece). The lighter/warmer guitar not surprisingly sounds very different with the Express. At the same knob settings on the Express, but just swapping guitars, the flame top is very bright! BUT, you roll back the Tone down to about 4 (yes 4!) and wow, it warms right up but retains its clarity. Amazing. I run the Tone at 7 on the quilt top. Both guitars sound monstrous. I can get very modern or Pagey tones. I have really found the warmer tones by working the guitar's Volume and Tone knobs.

I am using 820R at the entrance of the first two grids.

strato17 · Post by **strato17** » Thu Dec 06, 2012 9:50 pm

Hey everyone,

Just wanted to give an update. I took my Francesca clone and updated it to Ingrid status:

-33K on pin V1-7
-820R on pin V1-2
-Added an additional 0.0022uF mallory cap in parallel at C8
-Upped the PI Smoothing cap value to 500pf

The amp now sounds monstrous. The sound is SO much more balance and round to my ear. Nearly all the harshness I had is gone. I am more than pleased. The bass response is unreal. I have to back it down with some guitars or else the low end can get a bit muddy. I am LOVING THIS however.

Thanks for all the help everyone. Also, can anyone double check these voltage values and make sure everything looks ok? I might try a different PI tube.

Post by **Colossal** » Thu Dec 06, 2012 10:24 pm

strato17 wrote:Hey everyone,

Just wanted to give an update. I took my Francesca clone and updated it to Ingrid status:

-33K on pin V1-7
-820R on pin V1-2
-Added an additional 0.0022uF mallory cap in parallel at C8
-Upped the PI Smoothing cap value to 500pf

The amp now sounds monstrous. The sound is SO much more balance and round to my ear. Nearly all the harshness I had is gone. I am more than pleased. The bass response is unreal. I have to back it down with some guitars or else the low end can get a bit muddy. I am LOVING THIS however.

Thanks for all the help everyone. Also, can anyone double check these voltage values and make sure everything looks ok? I might try a different PI tube.

I just added the additional 0.0022uF cap and swapped out the stock 47pF smoothing cap for 500pF. I already have 820R at both grids. Definitely bumped up the low end, and for the better. Still stayed tight though. Man, I gotta say that even with 500pF (yes 500) it still sounds very well balanced. Plenty of top end and great clarity.

strato17 · Post by **strato17** » Thu Dec 06, 2012 10:40 pm

Colossal wrote:
strato17 wrote:Hey everyone,

Just wanted to give an update. I took my Francesca clone and updated it to Ingrid status:

-33K on pin V1-7
-820R on pin V1-2
-Added an additional 0.0022uF mallory cap in parallel at C8
-Upped the PI Smoothing cap value to 500pf

The amp now sounds monstrous. The sound is SO much more balance and round to my ear. Nearly all the harshness I had is gone. I am more than pleased. The bass response is unreal. I have to back it down with some guitars or else the low end can get a bit muddy. I am LOVING THIS however.

Thanks for all the help everyone. Also, can anyone double check these voltage values and make sure everything looks ok? I might try a different PI tube.
I just added the additional 0.0022uF cap and swapped out the stock 47pF smoothing cap for 500pF. I already have 820R at both grids. Definitely bumped up the low end, and for the better. Still stayed tight though. Man, I gotta say that even with 500pF (yes 500) it still sounds very well balanced. Plenty of top end and great clarity.

Nice! I am definitely loving the 500pf cap as well!

Post by **Colossal** » Thu Dec 06, 2012 10:47 pm

strato17 wrote:The amp now sounds monstrous. The sound is SO much more balance and round to my ear. Nearly all the harshness I had is gone. I am more than pleased. The bass response is unreal. I have to back it down with some guitars or else the low end can get a bit muddy. I am LOVING THIS however.

Nice! I am definitely loving the 500pf cap as well!

Yeah, all the mods are keepers. Going to try 33k on V1 for fun.

eazilyled · Post by **eazilyled** » Fri Dec 07, 2012 10:35 am

I've just been staring at the Ingrid pics as I'm thinking of trying the mods.

Could that first grid stopper resistor be 1.1K (brown brown red)?

Decko · Post by **Decko** » Sun Dec 09, 2012 5:58 pm

Tillydog wrote:
JazzGuitarGimp wrote:...Based on what I am seeing, I would start by increasing the value of the 0.022uF coupling cap at the grid of V2 (pin 2).
Based on my experiences with a 4-4-0 which became an Express, that cap holds the key to the low end (it's C6 on the 'stock schematic').

It's down as 2n0, rather than 2n2. It is powerful medicine, and I think the difference is easily audible. I don't think that it's any coincidence that Expresses have been found with parallelled caps here, because I think that you may well need "cap values that don't exist". I experimented with 1n0 in parallel with various other cap values. I don't recall what I have there now (doesn't really matter!) - maybe 1n0 and 820p ?? You would need to go the other way. 3n2 on the original 4-4-0 schematic (1n0 + 2n2) gave waaaay too much bass for me in Express form. The truth lies somewhere in between!

Andy

I have to agree with Tilly here. Adding 1n0 definitely stepped up the bass response. In my case the response was a tighter more focused bass.

Regards,
Decko

sepulchre · Post by **sepulchre** » Mon Dec 10, 2012 7:54 am

strato17 wrote: Also, can anyone double check these voltage values and make sure everything looks ok?

Where did you get your "Expected" voltages? Those are not what I've seen, maybe I'm missing a file?

Post by **Colossal** » Mon Dec 10, 2012 3:21 pm

Decko wrote:
Tillydog wrote:
JazzGuitarGimp wrote:...Based on what I am seeing, I would start by increasing the value of the 0.022uF coupling cap at the grid of V2 (pin 2).
Based on my experiences with a 4-4-0 which became an Express, that cap holds the key to the low end (it's C6 on the 'stock schematic').

It's down as 2n0, rather than 2n2. It is powerful medicine, and I think the difference is easily audible. I don't think that it's any coincidence that Expresses have been found with parallelled caps here, because I think that you may well need "cap values that don't exist". I experimented with 1n0 in parallel with various other cap values. I don't recall what I have there now (doesn't really matter!) - maybe 1n0 and 820p ?? You would need to go the other way. 3n2 on the original 4-4-0 schematic (1n0 + 2n2) gave waaaay too much bass for me in Express form. The truth lies somewhere in between!

Andy
I have to agree with Tilly here. Adding 1n0 definitely stepped up the bass response. In my case the response was a tighter more focused bass.

Regards,
Decko

I concur with both of you. 0.004uF may be a bit much. I've got both caps in right now and after some days with it in, I think it may a bit bloated sounding. There is a bit of congestion on the attack with lower chords. Tubes make a difference so 0.004uF might very well be fine with some preamp tubes. The trick is to step up the low end without losing the separation and clarity. There is a difference in sound between the 5k2 and 6k6 taps. 5k2 is slightly more beefy but the tradeoff is a dulling of the clarity, harmonic, and dimensional qualities.

strato17 · Post by **strato17** » Wed Dec 12, 2012 2:37 am

sepulchre wrote:
strato17 wrote: Also, can anyone double check these voltage values and make sure everything looks ok?
Where did you get your "Expected" voltages? Those are not what I've seen, maybe I'm missing a file?

I got it from the Express Files thread, 2nd post:
https://tubeamparchive.com/viewtopic.php?t=5691&start=0

strato17 · Post by **strato17** » Wed Dec 12, 2012 2:44 am

Here is a quick clip I made of my Express with the updates. 335 straight in, 4x12 with V30's, raw recording. All knobs are at 12:00, bright switch is in the 500pf position. I'm definitely loving the changes. PLENTY of bass, and the sound is way rounder.

Post by **Colossal** » Wed Dec 12, 2012 4:22 am

strato17 wrote:Here is a quick clip I made of my Express with the updates. 335 straight in, 4x12 with V30's, raw recording. All knobs are at 12:00, bright switch is in the 500pf position. I'm definitely loving the changes. PLENTY of bass, and the sound is way rounder.

I absolutely love the sound of a 335. Those pickups have the magic. Very cool!

eazilyled · Post by **eazilyled** » Wed Dec 12, 2012 8:00 am

Sounds great. Really fat sound!

Roe · Post by **Roe** » Wed Dec 12, 2012 9:52 am

too fat for me

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