I have a few questions since I don't know that much .

[catnine]

 When gain is defined this is what is needed to amplify a small signal and there are three of more stages preamp to output tubes?

 When distortion is described  this is overdriving a gain stage creating breakup/ clipping?

 I notice on fender amps that the ones that use the BF tone stack have a bypass cap after the tone stack to bring the gain back that was lost due to the BF tone stack . I notice when the stack is a vol and tone/treb cut there is not bypass cap after the tone stack . talking about amps like SF champs and P-P princetonsie brown then BF .

 Is a LTPI better than a split load PI or is the LTPI just to offer more drive for larger output tubes. I have seem LTPI in Bf deluxes and even an early tremlolux 5G9 and split load in princetons and twed deluxes and most all tweed fender amps .

 Is there any point in replacing a split load with a LTPI ? Is there a different tone difference in the two?   

 

[HotBluePlates]

HBP has left the building.

[navdave]

Differences? Yes. I like both check out this guys website he explanes phase inverters pretty indepth.
http://www.valvewizard.co.uk/

[catnine]

And they're all over the map, aren't they?

 Yes they are , but there is a method to my madness.

Some people overuse the term "clipping" in places "distortion" might be more appropriate

.

 I get confused by all the terms that's why I asked .

Some people disagree with my terminology.

 I felt you described quite well .

I notice on fender amps that the ones that use the BF tone stack have a bypass cap after the tone stack to bring the gain back that was lost due to the BF tone stack . I notice when the stack is a vol and tone/treb cut there is not bypass cap after the tone stack .

I guess Fender didn't feel they needed extra gain to make up after the lower-loss, simpler tone circuit.What is the bias voltage of the output tubes being driven by the long-tail in the amps you've looked at? How big is the B+ supply at the phase inverter node?

 I knew the first part just pointing it out . I don't know what the bias voltage is or the B+ for the LTPI

How does that bias voltage compare to the bias voltage of amps that use the split-load inverter? How big is the B+ in these amps at the phase inverter node?

 I will find that out tommorrow

"Is the split-load doing its job? Are the output tubes distorting before the phase inverter"

I wish I knew . The amp does not breakup at all until it's almost at 10 on the vol. How can I tell?

"Question: What color pick do you use?"

White clayton 1.52mm

Thank you HotBluePlates for explaining it all so well and trust me it does help and thanks for taking the time to offer an answer.

[HotBluePlates]

HBP has left the building.

[catnine]

HotBluePlates:

 I'll try that . I know the bias on this build is - 35 VDC on pin 5 of the JJ 6V6's and the 6V6's are at 18.8mA . Yet since the AC line varies from 118 VAC to 120VAC that can change so I can have 410 VDC on the plates to 417 VDC.

 I don't know if you are interested but the build is this. I built a 5E3 as far as the tube layout goes and then since I had only 2 input jacks and 1 tone and one volume what I did was take the 6G2 princeton from the inputs , used the 6G2 tone stack and then spliced the out put(wiper) of the vol pot to the grid of the second gain stage a 12Ax7. The 6G2 uses V1 for the preamp and second gain , the 5E3 V1 is only the preamp a 12ay7 and V2 is the second gain and split load PI . So mine is 1 triode of the 12ay7 preamp/ 6G2 tone stack, and then a 12ax7 V2 just like the 5E3 and then the 5E3 power section only adj/fixed bias. I used the same dropping resister values of the 5E3 , 5k and 22K
 Yet when I built this amp I got an Allen Amps PT that is 325-0-325 @180mA and an Allen Amps OT that is a beefed up version to use with a BF deluxe . His PT is taller than what is used on a 6G2 or any P-P princeton they are 325-0-325 @70 mA. which is what fender used on a BF and SF champ . If I had used the dropping resister values of the 6G2   1K and 10K  the voltages would have been to high.
 Since the 5G9 tremlolux is a lot like the 5E3 only it has a LTPI and fixed bias 6V6's I thought I could use the values of the 5G9's LTPI to insert it in my build even if my voltages are a bit higher they are close. Then again it may not even be worth the effort because I may find I didn't change anything at all as far as the general tone and sound go or created a overdriven monster which I would not be pleased with . I only bring this up because I can see how the 5E3 is a distortion machine and just using the simple tone stack of the 6G2 made this a clean sounding amp with a solid bottom end and just maybe , and I say maybe it might work . My gut tells me it won't sound the same as the build I have now. I have no idea how different the LTPI will sound in place of the split load I have now. I have read the 5G9 stock sounds a lot like a 5E3 but these were not my ears hearing this.

 To be quite honest if I had the funds to build another amp I would do this and then see. Perhaps I should just leave well enough alone.

[Willabe]

Since the 5G9 tremolux is a lot like the 5E3 only it has a LTPI and fixed bias 6V6's 

Well kinda. If you divide the 2 amps into 3 parts and ignore the 5G9's trem you get, >pre>PI>PA.

5E3 and 5G9 have same pre but different PI's and different PA's, (5G9 has choke, both have no NFB) even though they both use 6V6's. So only 1/3 of the amps the same.

I've built both amps, still have them and to me they sound different but not drastically. The 5G9's cleaner and less compressed but not a lot. I love the 5G9's trem.



                        Brad      

[Willabe]

I forgot to say the B+ PS is a little different also.

5E3 has less filtering in uF values, 5E3 has 16uF for 1'st B+ filter node followed by a 16uF and 16uF nodes. The 5G9 has 40uF for 1'st B+ filter node followed by a 20uF and 20uF nodes. 5E3 has a 5Y3 rect. and 5G9 has 5U4 rect. + a choke. So 5G9 has a little stiffer B+ rail?


                   Brad     

[catnine]

I forgot to say the B+ PS is a little different also.

5E3 has less filtering in uF values, 5E3 has 16uF for 1'st B+ filter node followed by a 16uF and 16uF nodes. The 5G9 has 40uF for 1'st B+ filter node followed by a 20uF and 20uF nodes. 5E3 has a 5Y3 rect. and 5G9 has 5U4 rect. + a choke. So 5G9 has a little stiffer B+ rail?


                   Brad     

 Mine is not just like the 5E3 and has a 30uf first filter cap and two 16uf and my voltage is higher and the tone stack is the one used on  6G2 just simple tone and vol. so it wouldn't sound like either the 5E3 or 5G9 .

[Willabe]

the tone stack is the one used on  6G2 just simple tone and vol.

5E3 and 5G9 have the same simple 1 knob tone control as 6G2.

5E3 >16uF >16uF >16uF = 48uF total

(Your) 6G2 >30uF >16uF >16uF = 62uF total

5G9 > 40uF >20uF >20uf = 80uF total

Yours falls in the middle between the 2, not a lot of difference between the 3 amps B+ filtering uF values. (Although the 5G9 does have a choke.) Don't know what rect. tube your amp is using or what the B+ node cv's are, but I'd bet if we had all 3 in the same room with the same speaker/cab and played the same guitar through them they would sound different but not drastically.

Is a LTPI better than a split load PI or is the LTPI just to offer more drive for larger output tubes. I have seem LTPI in Bf deluxes and even an early tremolux 5G9 and split load in princeton's and tweed deluxe band most all tweed fender amps .

Is there any point in replacing a split load with a LTPI ? Is there a different tone difference in the two?  

Yet when I built this amp I got an Allen Amps PT that is 325-0-325 @180mA and an Allen Amps OT that is a beefed up version to use with a BF deluxe . His PT is taller than what is used on a 6G2 or any P-P princeton they are 325-0-325 @70 mA.

Since the 5G9 tremolux is a lot like the 5E3 only it has a LTPI and fixed bias 6V6's I thought I could use the values of the 5G9's LTPI to insert it in my build even if my voltages are a bit higher they are close.

I have no idea how different the LTPI will sound in place of the split load I have now. I have read the 5G9 stock sounds a lot like a 5E3 but these were not my ears hearing this.

What I am trying to say is the tone difference between the 5E3 (split load PI) and 5G9 (LTPI) that I built is not a whole lot. (And that includes the change of tone from the 5E3's cathode bias PA and 5G9's grid bias PA.)

I only bring this up because I can see how the 5E3 is a distortion machine and just using the simple tone stack of the 6G2 made this a clean sounding amp with a solid bottom end and just maybe

What you described sounds like a 1 channel 5E3/5G9 pre with a split load PI and grid bias PA with ~417dcv on the 6V6 plates.

Fender/Vox/Marshall T/M/B tone stack has more loss than a single treble cut tone control. So your tone control has > less loss = less signal= more gain. That's not what's making your amp cleaner. Grid bias with higher B+ and that your PT is way over rated for current is why it's cleaner with a solid bass end IMO.   


             Brad    

[catnine]

 The 5E3 and 5G9 may have similar tone /vol circuits yet the way they are wired makes a huge difference. Mine does not have 2 vol pots and the vol and tone pots are not wired the same way . Yet since you siad there is not much difference between the 5E3 and 5G9 sound wise than that's the main point of it all. So even with the LTPI in place of the split load  my amp wouldn't change enough to make the change worth it.

 Thanks for your input , at least I know the 5E3 and 5G9 don't sound that different. I had the 5E3 tone stack wired in my build in ther beginning but it broke up and had the same overdriven sound a 5e# had so I changed the 5E3 tone stack to the 6G2 and just by doing that the amp changed completely. It went from the overdriven sound to a clean sound with no loss in bottom end , if fact changing the cathode bias to fixed made quite a different as well.

[Willabe]

The 5E3 and 5G9 may have similar tone /vol circuits yet the way they are wired makes a huge difference. Mine does not have 2 vol pots and the vol and tone pots are not wired the same way .

I asked about this wiring not long ago here's the thread;

http://www.el34world.com/Forum/index.php?topic=14764.0

Yours is (only) minus 1 volume pot and your tone/vol are wired 180 deg. from the 5E3/5G9 as far as the tone/vol pot wipers are being fed from the 1'st stages coupling cap and feeding the next tube stages grid.

This in and of it self should not be drasticly different sounding. Read the link. Must have had it wired wrong or bad componant.


                  Brad                  

[catnine]

Brad that only shows the vol pot not the complete circuit . I assure you mine is wired proper per the 6G2 .  maybe the 5E3 uses linear pots I can't find that but HotBluePlates stated B type pots mine are 1 meg audio taper . The 6G2 and 5E3 are not wired the same way at all , they may use the same value caps for the tone but that's where it ends. And the caps on mine are the proper value too. It is a very simple tone stack.

 I know for certain the way mine is wired changed the amp completely . Try it , I can't explain how but it was day and night much more so than changing a 6G2 tone stack to a BF tone stack . The tone stack on the 5E3 the plate of V1 goes through the entire 1 megs pot trace with the caps before and after and then the wiper is tied to both 1 meg vol pots entire trace to ground and the grid of V2 and the vol pots wipers are tied to the V1 plates . So the tone and vol inter-react . This is not the case with the 6G2 .
 
 I first wired my build just like the 5E3 with one exception , I only had one vol pot and two inputs so take away the extra vol pot and one triode of V1 yet you still end up with the same early breakup 5E3's are known for so all I did was change the circuit to the 6G2 and I can set the vol level at any point and set the tone where I want it and one does not affect the other where at least I can hear it. I just have more treb or bass and more or less vol level. At one point I installed the BF tone stack simply because the fender music master bass amp chassis I used is the same size as a SF champ and I had a BF champ faceplate and the extra hole was already in the chassis and the amp lost it's open sound and became sterile sounding so I put  it back plus even though I had the 25 uf bypass cap across the second gain stage 1.5K cathode resister to ground as does the 5E3 the amp sounded sterile.

[Willabe]

Brad that only shows the vol pot not the complete circuit . The 6G2 and 5E3 are not wired the same way at all , they may use the same value caps for the tone but that's where it ends.

Yes, but the main differance is on the 5E3/5G9 the volume pot's wiper is fed from the plate coupling cap and the 6G2 volume pot's wiper is feeding the recovery stages grid. I drew up the whole circuit for comparison side by side attached at bottom.

The 6G2 and 5E3 are not wired the same way at all

So the tone and vol inter-react . This is not the case with the 6G2.

The tone and volume are just flip/floped. I don't see why the tone/volume on the 6G2 would'nt act the same.

maybe the 5E3 uses linear pots I can't find that but HotBluePlates stated B type pots mine are 1 meg audio taper .

The pots taper will only change how fast or slow the volume/tone change not their interaction or not.

I think HBP was talking about drawing A or drawing B and not the volume pots taper?

                  
                              Brad      

[Willabe]

The interaction I get on my 5E3 and 5G9 are because when turning up or turning down the tone control you keep more or throw away more signal. So turn up the tone and the amp not only gets brighter sounding but it gets a little louder. Your's has to work the same. Yours is either keeping more signal or throwing more signal away to ground. They both work the same.

Maybe HBP, Sluckey, PRR, or someone will chime in on this?


                    Brad      

[catnine]

Brad : like I said , it makes a huge difference . and take out the 10k resister off the grids that is not on any of these schems .

 It's not just flip flopped as far as the tone being before the vol 5E3 but the path to ground is different . Just look at the tone pot . The 5E3 has the tone setup so you have the 500pf cap off the V1 plate then through the 1 meg path to the (.047) cap to ground . the tone pot wiper is tied to the vol 1 meg path to ground as well as the vol pot 1 meg path to ground and both are tied to the V2 grid . The main diff is the vol pot on the 6g2 the wiper of the vol pot is to the grid and the wiper of the 6g2 tone pot is not tied to the grid through the wiper. It's not the same thing. Look at the vol pot on the 6g2 it gets it's signal right off the plate of V1 (before) the tone pot so if you turn the vol pot all you are doing is throwing away or adding signal right? Now the tone pot does not alter the vol pot where signal is concerned , it just cuts bass. This is because the wiper of the vol is not set up like the 5E3 .

[Willabe]

take out the 10k resister off the grids that is not on any of these schems.

That's just a 10K grid stopper, won't make any difference about what we're talking about.

It's not just flip flopped as far as the tone being before the vol 5E3 but the path to ground is different.

It doesn't matter which pot is before or after the other, the path to ground is still the same. That is as far as the pot wipers are concerned, depends where you set them. But because of that they have to work the same.

The link I posted was about how the volume pot wiper is wired. It was brought up that if the pot wiper is fed from the plate coupling cap it will change the load of that tube. The volume pot's wiper orientation not the tone pot was questioned about interaction.


                Brad      

[catnine]

Yes the path to ground is the same but the path of the signal is not the same.

[Willabe]

Look at the vol pot on the 6g2 it gets it's signal right off the plate of V1 (before) the tone pot so if you turn the vol pot all you are doing is throwing away or adding signal right? Now the tone pot does not alter the vol pot where signal is concerned , it just cuts bass. This is because the wiper of the vol is not set up like the 5E3.

Yes I said that.

Yes, but the main differance is on the 5E3/5G9 the volume pot's wiper is fed from the plate coupling cap and the 6G2 volume pot's wiper is feeding the recovery stages grid.

But the tone pot still keeps signal or throws signal away. Same thing as far as the next tubes stage is concerned.


                             Brad    

[Willabe]

Yes the path to ground is the same but the path of the signal is not the same.

Depends where the wipers are set. I still think they have to work the same.    

(I'm actually hoping your right it would, could come in handy on certain builds.   ) 


                   Brad    

[catnine]

Yes the path to ground is the same but the path of the signal is not the same.

Depends where the wipers are set. I still think they have to work the same.    

(I'm actually hoping your right it would, could come in handy on certain builds.   ) 


                   Brad    

The volume controls of the 5E3 are wired so the output of the first preamp tube's plates are coupled into the volume pot's wipers and the second preamp amplifier stage (the A section of the 12AX7) is running wide open with only a little grid attenuation of around 470K to 500K, the two 1M volume pots in parallel to ground. 
With an audio or log pot, this odd way of feeding the volume controls and the next amplifying stage, makes for super fast response and the amp volume comes up much faster then with the volume pots wired the other way around, as in the 6G3 Deluxe. 

[Willabe]

The volume controls of the 5E3 are wired so the output of the first preamp tube's plates are coupled into the volume pot's wipers

Yes, that's why I posted the link to the thread I started on that wiring.

and the second preamp amplifier stage (the A section of the 12AX7) is running wide open with only a little grid attenuation of around 470K to 500K, the two 1M volume pots in parallel to ground.

Now that's a good point. Hmmmm......   

Could it be that because the recovery stage is running full at all times in a 5E3/5G9 that any treble cut or boost is much more noticable than the way the 6G2's volume/tone are wired up?

You might be right, never thought of it that way.


                     Brad          

[catnine]

I'll just trust fender on this . The brown deluxes came after the tweed deluxes and then the BF . Each step brought the amps closer to less breakup and more headroom . So the brown deluxe the 6G3 had the same tone stack as the 6G2 only two vol and two tone . Even though the 6C3 had a LTPI and more voltage I do feel if the input signal change the tone stack made a lot of difference.

[phsyconoodler]

The tone stack doesn't have much to do with clean headroom.The later Fender amps had higher voltages throughout the amp,preamp and power sections.That's where the clean headroom comes from.
  If you modify an older Fender for more voltage in those areas the clean headroom increases dramatically.
The reason for the tone stack is versatility.Players demanded more tone-shaping,so here comes the treble,mid,and bass tone stack.
  Fender experimented with negative feedback early on too,and that has a huge effect on headroom too.The later Blackface and Silverface amps being prime examples.
 

[catnine]

I agree with the higher voltages and today for new builds most PT's, even if you were to build a 5E3 of even a SF champ you read how to lower voltages using zener diodes or altering the values of dropping resisters. Also at least in my case, the PT has twice the mA rating on the HT secondary windings so with the same set of tubes you are not pulling the PT down voltage wise. 

 Still even with the higher voltages if I were change the tone stack on a Sf champ with the same voltages to a 5F2A princeton tone stack and removed the second gain bypass cap the amp will change as far as tone and point of breakup.

 I don't know much about why things work for the most part , certainly not even close to many here . I can say even with the same voltages across the board changing the tone stack from the type the 5E3 has to what the 6G2 has changed the entire amps sound . Mine was just a build in progress . I looked for a simple fender P-P schematic that I could build in the chassis at hand not knowing anything about tone stacks or their affects , then did the 5E3 . Once I heard the result I tried to figure out what I could do to change that and knew later fender amps were aiming toward a cleaner tone and more headroom so I chose the 6G2 tone stack and the result was closer to what I was after. Then I looked into how the power tubes were biased and built a adj/fixed bias , the amp sounded tighter . Then I realized the difference in preamp tube gain so I used the 12ay7 instead of the 12ax7 again it was me experimenting. The break up shifted to a much higher point ( more headroom) yet the vol of the amp did not change in noticable volume levels . So at this point I never changed the voltage or dropping resister values from the 5E3 , I then decided since the 6G2 is real close to my build and 12ax7's  had plenty so I added a switch to add the 6G2 NFB and remove the second gain stage bypass cap  stuck in a 12ax7 yet this brought me back to an earlier breakup. I did put the 12ay7 back in and if I switch out the NFB and bypass cap I have a drop in volume but a tighter sound . This  is fine I can use either tube depending on what I want. It was all a trial and error that gave me what I was after yet I prefer the 12ay7 and no NFB and the bypass cap in play. Tried the BF tone stack and even with no NFB the amp lost all it's appeal .