Fender Hot Rod Deluxe Discussion

Carmassi had a real good rock feel on the drums.
I love playing Rock The Nation full tilt on the car stereo with the windows down while getting gas, the old timers get terroried by that one, they can't handle it.


A guy at a dead show must have been on acid, because after the first number, he took off all his clothes and left them on the floor in a pile.
Needless to say, some freak, probably a drinker, stole the guys clothes!
I do not know how he got home, cool dead heads probably took care of him.

They don't do stuff like that anymore nowadaze.

We lost at least one or two people at the Day On The Green shows, fell off the back of the Oakland Stadium.

People used to get iced all the time.
The Who an Cinci, security guard at a ZZ Top show got shanked becuase he wouldn't let some freak climb the light tower.

Altamont, of course.

I sold my hole for rock and roll, and payed a heavy toll...

just kiddin, I don't roll like that.

Go for the Machless circuit, the other way, you need a dual pot and an extra set of coupling caps, which are big, and which probably will not fit inside the chassis without being ugly.

If you want compression, which might help sustain, you can switch to cathode bias.

If you don't like vibrato, you can use that tube for an extra gain stage, that way you don't have to punch a new hole.
This is a common mod to make a Princeton sound like a Princeton Reverb, which uses 1/2 of a reverb tube for extra gain.

You can rebias the first stage by swapping in a 1 K resistor.
If you like that, do the same on the next stage.

You can replace the first tube with a 12AY7, this will drag more current thru the power resistor in the supply, dropping the B+ which will take away brittle bite, which means a warmer sound, and with the dropped gain, you can crank up the front end all the way.

If this is any Two channel black or silver face, you can decide which channel you want to play thru, then rip out the other preamp tube for the channel not in use.
Since tyhe tubes share the same cathode resistor, removing one of the tubes causes the bias on the other tube to drop, increasing the stuff you are after.

Also, short out the 68 K on the input jack, it can only harm, it can do no good unless you like to share your amp with someone at a jam, and we all know how territorial git players are when it comes to grade school garage tactics like that.

first band was

Me into a Princeton Reverb along with the vocals,
Bass and Rythem guitar shared my Vibro Champ.
Since I was the lead guy, I got the equipment bump up to the 8 inch speaker, whoop de do!~

Still the funnest band, the first band is always the best.
Been trying to recreate that feeling for a long time, no luck yet.

[quote author="CJ"]Still the funnest band, the first band is always the best.
Been trying to recreate that feeling for a long time, no luck yet.[/quote]
I know what you mean. At the time you think "it only gets better from here, but no mater how much you improve, that great feeling you had becomes more and more elusive. Next thing you know, you're pushing 50 and suddenly realize those days are gone for good.

That's so true.

My first band was back in high school days--I was about 16. We played in our singer's room after school. We had four guys and two amps; the singer plugged his mic into the bass player's amp and I had a 1-12" combo all to myself. The singer's brother bashed away on a tiny Gretsch drum kit. It was ragged, raucous and FUN. And it was all downhill from there.

Well, I’ve messed around with this thing off and on all day and ended up putting C3 back on the Drive relay like it was and removed the hi-pass “sparkle” caps. The new speaker adds enough sparkle on it’s own. I’m leaving C8 out, though and that frees up Q1. I still need bleed off more highs when in More Drive mode, so I’ll use Q1 to somehow do that.

I forgot to mention – there was originally a 47uF across R10 (the bright switch cap, C4 had been moved to VA2’s cathode). I read somewhere that someone else’s was like this, so makes me wonder if Fender did it? The schematic is 5 years older than my amp, so could have been a factory mod since then. If anyone else’s is that way, let me know cause I’m curious. Needless to say it had little headroom. Also, R44 was a 56K instead of 180K, so looks like whoever did it attempted to tame the big BP cap by lowering the voltage divider ratio going into that stage. It sounded great when the clean volume was cranked tho, if one didn’t need the headroom. I left 56K in there because there is still plenty of gain on the Drive/More Drive modes.

I can't get over how much better it sounds with the NFB removed. I think I'll turn the Presence pot into a "cut" circuit between the PI and PTs. It's still a little bright over all, so that will let me dial some of that out.

Buying a used amp is like a box of chocolates – you never know what you’ll get.

negative feedback takes away the dirt under your fingrnails, in other words, it cancels your personality.
ever wondewr why every body sounds the same with a strat/fender?
i mean, of course there is a little variation because of tyhe git and player, but the amp sounds the same!@

controls, or cancels, if y
it is your job, as a fender player, to not notice!

that way, he can sell an amp that will not feed back anywhere.

it is a mod that really favors the super reverb, the fender i hate the ost... wanna be marsh with 10's but no joy, only for harp, and even then, you could do better with a kendrick harp amp...

Ok, I know some of you have been cliff-hanging since my previous post :wink: so I thought I’d make one more post about what I ended up with. The new tubes, speaker, and OT changed the tone somewhat, so these may or may not work as well with a stock amp.

This thing had too much gain in the early stages killing the clean headroom and causing blocking distortion, mud, and brittle highs in Drive and More Drive modes. I mentioned before that I removed C8 and the 47uF “mystery” cap across R10 (not on the schematic). Next I tried values from 47uf to .68uF in C1’s position, but ended up removing it altogether as well. I now have no Rk bypass caps other than the 22uf switched across R21 in More Drive mode. At this point there was much more headroom with the volume control breaking up around "8" (before it broke up around "2"). However, this made the overall gain a little too low for my taste, so I raised R44 to 100K (it was originally 57K, not 180K like the schematic shows). This gave me just the right amount of gain all the way around. Now the clean volume starts to break up just after "6" and the tone is more consistent for all three gain stages. You can vary the overall gain just by adjusting R44 since it controls both volume and drive levels going into the next stage.

For C23, I tried values from the original 1.5nF up to .022uF, but ended up with .01uF for my taste. I also raised R52 to 220K.

I connected C3 and R27 back to K1b as it originally was, but reduced C3 to 110pF. The Drive mode became more alive with a nice jangly tone similar to the clean mode (it was just a tad bright with C3 removed). Since C8 was disconnected, I connected another 250pF cap in parallel with C3 to be switched in via Q1 when selecting More Drive to further tame high-end in that mode. I also changed C11 back to its original value of 390pF. As I stated earlier, the Master pot, R26 was changed to 250KA and now has a much more linear feel (You can get the exact 250KA Fender pot from Antique Electronics)

I temporary reconnected the bright switch, but even without it turned on I could max the treble and mid controls, and kill dogs across the street with the bridge PU of my strat, so I decided to just do away with it.

I continued experimenting with tone stack values and settled on C7 – 470pF; C 5 & 6 – .022uF; R12 – 87K. Just to give the unused bright switch something to do, I cut it’s traces to isolate it from the rest of the circuit and wired it to switch a 1000pf in parallel with C7 (470pF), which lifts the mid peak almost even with the bass and treble curves to create a punchy mid boost when engaged.

Now moving on to the negative feedback circuit… My new OT has 8, 4, & 2 ohm taps. Of course, the 8 ohm tap is connected to the 8 ohm speaker, but the schematic shows the 4 ohm tap connected to the NFB on the stock amp. I originally had the NFB connected to the 8 ohm tap and it was too sterile. Connecting the 4 ohm tap to the NFB was better, and switching to the 2 ohm tap was more better. I also lowered R68 to 3.8K and there was the happy medium. It now has much of the no–NFB feel, but with a little more high & low frequency control overall, plus, I still have use of the presence control. I put a SPDT in the second speaker jack-hole to switch between the 4 and 2 ohm taps for NFB.

I had mentioned earlier that I changed all coupling caps to orange drops, but I honestly can’t tell that it made much of a difference. Given the extra wear and tear on the pc board (which is VERY cheap, by the way) I personally wouldn’t change these if I had it to do over, unless of course I was going to change the value anyway. I don't think the original caps are all that bad. Currently I have all orange drops and silver micas in the signal path.

One last thing I may do is add 2 or 3 more FETs configured like Q1 and Q2 to parallel 1.5Ks in some combination across R10 and/or R17 and/or R21 to give a little more boost to the More Drive mode. Not that More Drive doesn’t have enough gain (it does!) but I’d like to increase the delta between Drive and More Drive. I tend to like the Drive tone in the lower half of the Drive control range and the More Drive tone in the upper half of the range, so it would be more useful to me when switching between them. I also have pin 11 of K1b free to switch in a tweak or something when in Clean mode, but it sounds fine like it is.

Anyway, it’s a better sounding amp now, so I guess I should quit while I’m ahead. Besides, those poor pads on that cheap board couldn’t take much more abuse.

Hi mates, here s a little mod, really not impressive but very convenient in many real life situations :
http://img4.hostingpics.net/pics/633116HotRodDeluxeMOD.png

Saint Gillis, I'm looking at your mod above, you say its convenient in live situations...but what does it change?

gmacburnie said:

Saint Gillis, I'm looking at your mod above, you say its convenient in live situations...but what does it change?

Click to expand...

In term of sound it changes nothing. In term of gain, you can raise the preamp to a 4, 5 or 6 level and get a nice sound also easily trimmable without killing everybody...