On a 5E3 why do they use a 1.uf coupling cap

[catnine]

I see this on only older fender tweed amps that are push pull with the Vol Vol tone stack setup . On all later amps they went with a .022 uf coupling cap between the preamp tube and second gain stage until you get to the later BF tone stack . My main question is why did these 5e3's use the 1. uf coupling cap , was it because of bass and the tone stack they used?

I started out with a two input 5E3 using one triod of the 12AY7 then did n't like the affect of the 5E3 stack so I make it like the brown 6G2 princeton . At that time I changed the bias from cathode to adjustable fixed and could run either 6V6's of 6L6's . With the OT I have I decided to go with one 8 ohm 12 , this OT can do one 8 ohm load or a 4 ohm load with 6V6's. I had a weber 50 watt silver bell in it and found it great but in order to get the speaker moving I had to plug into the low input with a strat and back off the guitar volume but since I now use this amp at home only even this was too loud and sounded dry not pushing the speaker . I also noticed that the tone pot was not capable cutting bass unless it was mutted . I was told to change the 1.uf coupling cap to a .022 uf , it helped but still was not the answer .

I ended up installing a weber alnico sig12 s and now have great tone at low levels and a tone that is usable.

I do find JJ EC83 needs more treble than a long plate rCA 12ax7 , jj on 9 is like the RCA on 5 .

I ended up basically with a 6G2 with the 5E3 V-1 as the preamp and V-2 as the second gain and PI and a power section of a 5E3 other than the adj/fixed bias and a switch to break the 25uf second gain bypass cap and switch in a 6G2 NFB loop. I like the bypass cap and no NFB best.

If i install a 12ax7 in V-1 and switch the NFB in the amp is too gainy not like a 6G2 and possibly because of my higher voltages . It does sound good with NFB and a 12AY7 however.

[black_labb]

its what they decided to use. was probably a common value in the rca circuit book that the early designs came from. leo made amps to amplify guitars, not to get that perfect tone. specific tones werent around to aim for. if it worked, was reliable and was inexpensive then thats what was done.

change values around a bit until you find what you like.

[cminor9]

also, consider that Fender was probably thinking of Teles or Strats (single coils) for use with the 5E3. In my experience, a 5E3 with .1 coupling caps sounds fine with single coil pickups. It's when you run a humbucker thru it that it gets all muddy.

If you ever decide that you want to have a 5E3 again, try changing the first two coupling caps to .02, and the rest to something like .47. It'll be fine then. There are other simple mods that you can make to a 5E3 to make it more flexible, but that's about the most important one.

[mbratch]

I agree with cminor9's rationale for the .1uF coupling caps.

I changed mine all to .047uF. That and remove the 25uF cathode cap on V2 and you've gotten rid of a lot of "gaininess" (and, of course, it's 5E3-ness since that's what characterizes a 5E3) without adding NFB or changing PI. Just that 25uF removal from the original circuit, in my experience, made a significant difference. I'm now thinking of putting a switch in place of the 2nd speaker jack to switch that cap in or out. It would really be cool to footswitch it.

[Bruce / Mission Amps]

The tone of the day was much darker and jazzy then it is now, but I agree with controlling the brightness found in Teles and Strats too.
Also, the two 1m volume controls are in parallel in these amps... where the total is actually less then 500K in most amps... so it would be better if the coupling caps used would be twice the size (100nF instead of 47nF) to keep the RC time constant more in line.
Although I tune mine a little differently and it really depends on what guitar is being used (I don't care for Les Paul guitars through a stock tweed Deluxe), I like to use .033uF myself on the bright channel and .047uF in the normal with single coil pickups.

[Old Tele man]

(I don't care for Les Paul guitars through a stock tweed Deluxe, I like to use .033uF myself on the bright channel and .047uF in the normal with single coil pickups.

...excellent point, because most people forget about the vastly different input loading differences between a Fender single-coil pickup and a Gibson dual-coil 'humbucker' pickup.

...granted, this difference mostly affects only the first preamp tube, but those changes are then passed along through all of the following circuits.

[catnine]

I never used humbuckers , never cared for their sound . I just use single coil strats and with my amp now basically a 6G2 without tremolo or NFB loop and with a 25uf second gain bypass cap still in place I get plenty of lows and mids and smooth highs .

I don't know about amp design , I can build an amp off a schematic and remove sections like the tremolo 6G2 circuit and build a quiet amp but that's about it other than understand how to do certain mods .

I didn't have the room in my chassis for 4 inputs and two vol and one tone control so I used only one triod of V-1 and did have the vol and tone wired like a 5E3 which is not quite the same at all as the two 5E3 vol pots but still the affect was real loud at 3 and just more breakup past that point so I went for the later brown 6G2 front end and looking at the schematic there is a .022 uf bypass cap after the 12AY7 which is what I have now .

I did notice some difference changing it from the 1. uf coupling cap with a heavy duty 12 inch speaker but not that much difference .

My build does run higher voltages than a 5E3 so that may make the difference . I see sometimes small changes make a lot of difference .

I used a fender music master bass amp chassis for my build and since it's set up with two inputs and a vol and tone , just enough room for an extra 9 pin and a octal for the rect tube plus I could find a larger more powerful allen amps PT that was a drop in fit giving me the options of several simple fender amp builds since there is not much real difference between the 5E3 and 5E5 or the 6G2 or harvard 5F10 just a matter of no tremolo (6G2) or extra inputs on the 5E3 which I never woud need.

They are simple basic amps wihtout much to suck out tone only to add it back if you use later tone stacks and more controls , I like it simple . No extra gain and rows of knobs and switches for me to get lost with. One channel and two knobs and an input jack and I am happy as long as the amp produces the tone I'm after and by luck this one does.

[mbratch]

With the .047uF configuration I have, it sounds great with both my strat (vintage style pickups) and my humbucker guitars. My ES347 cops a decent vintage Kenny Burrell tone, and my Hamer with Seth Lovers rocks nicely. I use a Weber 12A150.