How to get more overdrive - edit: got it!

[Darkbluemurder]

Hi guys,

I used my Fender Deluxe II Reverb which I modded to a D-clone (90 era with HRM) for rhythm which was great. I want to use it for solo work now. In order to cut bass and treble I used a 220k network with 100k/250pf going to ground before the 220k and 22k going to ground after the 220k and going into the 68k. While this achieved what it was supposed to the overall gain is now too low. I would like to have more. Gain pot is 250kA, OD level is 1MA, coupling cap before OD 1 is .047uF. Mid cap is .01uF (changed from .047uF which massively increased bass and low mids). I do not want to change anything which affects the clean tone.

What to do? Increase gain pot to 500kA or 1MA? Go to non-HRM? Anything else?

Thanks for all your contributions. I am loving this site!

[groovtubin]

Hi guys,

I used my Fender Deluxe II Reverb which I modded to a D-clone (90 era with HRM) for rhythm which was great. I want to use it for solo work now. In order to cut bass and treble I used a 220k network with 100k/250pf going to ground before the 220k and 22k going to ground after the 220k and going into the 68k. While this achieved what it was supposed to the overall gain is now too low. I would like to have more. Gain pot is 250kA, OD level is 1MA, coupling cap before OD 1 is .047uF. Mid cap is .01uF (changed from .047uF which massively increased bass and low mids). I do not want to change anything which affects the clean tone.

What to do? Increase gain pot to 500kA or 1MA? Go to non-HRM? Anything else?

Thanks for all your contributions. I am loving this site!

put the 220K/500p COMBO to ground at entrance ( lose the 100K combo) , then EXPERIMENT with the resistor going across, also UP the 22K to at least 33K, just experiment. Thats a old network, but works great for blues.

[dogears]

Hi DBM,

Here is an excerpt from what I posted to Harris. Do these changes. And DEFINATELY LOSE THE ANCIENT WIERD NETWORK. 100% sure. Use the network I detailed and only use the amp OD with the PAB engaged.

Here is what to do. DO all I suggest and then evaluate. It is a system.

1) Reduce the V2a cathode resistor to 2.7k to 3k. I use a 2.87k in mine. (for the OD1 180k plate)

2) No local feedback on V1b.

3) Use a full 500pf bypass cap on the V2b grid resistor

4) Use a 150k-180k resistor to ground from the V1 dropping resistor. This simulates the FET and will lower the plate voltages of your preamp tubes. They are way high. Shoot for 200v on V1 and 220v on V2

5) The pre OD network must be 470k with 47pf bypass into 200k into 25k trim with 4.7k tail. THis is a lowgain network. Crank the trimmer and ONY ONLY ONLY use the amp in PAB boost mode. Adjust stack when in boost mode. Set the mids about 40% up, the bass about 45% up, and the treble up at about 30%

6) No snubbers on V2

7) HRM treble cap must be a 500pf (not the 330pf in the schematic)

8 ) Put a 5uf bypass cap on V1b. You need to slam the OD with bass and filter at the end.

[groovtubin]

Hi DBM,

Here is an excerpt from what I posted to Harris. Do these changes. And DEFINATELY LOSE THE ANCIENT WIERD NETWORK. 100% sure. Use the network I detailed and only use the amp OD with the PAB engaged.

Here is what to do. DO all I suggest and then evaluate. It is a system.

1) Reduce the V2a cathode resistor to 2.7k to 3k. I use a 2.87k in mine. (for the OD1 180k plate)

2) No local feedback on V1b.

3) Use a full 500pf bypass cap on the V2b grid resistor

4) Use a 150k-180k resistor to ground from the V1 dropping resistor. This simulates the FET and will lower the plate voltages of your preamp tubes. They are way high. Shoot for 200v on V1 and 220v on V2

5) The pre OD network must be 470k with 47pf bypass into 200k into 25k trim with 4.7k tail. THis is a lowgain network. Crank the trimmer and ONY ONLY ONLY use the amp in PAB boost mode. Adjust stack when in boost mode. Set the mids about 40% up, the bass about 45% up, and the treble up at about 30%

6) No snubbers on V2

7) HRM treble cap must be a 500pf (not the 330pf in the schematic)

8 ) Put a 5uf bypass cap on V1b. You need to slam the OD with bass and filter at the end.

i missed the HRM part, thanks for correcting me scott! , jim

[pedro]

Hi,

I can vouch for these changes - I followed Scotts advice on this a few days ago on these mods and have a different sounding amp now - lots of touch response on HRM OD mode now.

I am working up an amended schem based on the s3988009.jpg in the files section which details the recommended changes.

cheers
Pedro

[Darkbluemurder]

Guys,

Thanks for all your input. I experimented today with the amp. Basically I removed the HRM (I had a 470p treble cap in there together with a slope resistor of 39k). I exchanged the "wierd" network before OD 1 with a 220k series and 56k to ground (no trim). As for the rest I stuck to the Hybrid Rev A but kept the 250kA Gain pot for now. I used 500p snubber caps.

The result: enough gain on tap, smooth sound. A totally different amp. I will take it to the gig I play next Saturday to check it out. If it is too dark I replace the gain pot with 100kA and/or the snubber caps with 330p or 250p depending what I have left.

I like both the non-HRM and the HRM versions. It just happens that I seem to prefer the non-HRM for solo work.

[dogears]

DBM,

I definately suggest swapping the 250ka pot out. Use the 100kb and a .01uf coupler. You need to maintain the "correct" RC network knee......

If you keep the 250ka pot, you could try upping the OD1 coupler from the HRM .0022 to a .0047 or .0056 cap. What is in it now??? If you use a .01 with a 250ka pot, you will get way way too much bass and the tone will not be nearly as nice as if you get the right knee frequency.

Glad the changes helped. Oh, did you run a 100k trimmer or voltage divider before the 1M OD master? If your HRM was correctly implemented, you would have gone straight into the 1M

Lastly, you should revisit the HRM at some point. You never got to hear it as Dumble designed it. Had you have, you might have kept it!

Guys,

Thanks for all your input. I experimented today with the amp. Basically I removed the HRM (I had a 470p treble cap in there together with a slope resistor of 39k). I exchanged the "wierd" network before OD 1 with a 220k series and 56k to ground (no trim). As for the rest I stuck to the Hybrid Rev A but kept the 250kA Gain pot for now. I used 500p snubber caps.

The result: enough gain on tap, smooth sound. A totally different amp. I will take it to the gig I play next Saturday to check it out. If it is too dark I replace the gain pot with 100kA and/or the snubber caps with 330p or 250p depending what I have left.

I like both the non-HRM and the HRM versions. It just happens that I seem to prefer the non-HRM for solo work.

[Darkbluemurder]

Hi DBM,

Here is an excerpt from what I posted to Harris. Do these changes. And DEFINATELY LOSE THE ANCIENT WIERD NETWORK. 100% sure. Use the network I detailed and only use the amp OD with the PAB engaged.

Here is what to do. DO all I suggest and then evaluate. It is a system.

1) Reduce the V2a cathode resistor to 2.7k to 3k. I use a 2.87k in mine. (for the OD1 180k plate)

2) No local feedback on V1b.

3) Use a full 500pf bypass cap on the V2b grid resistor

4) Use a 150k-180k resistor to ground from the V1 dropping resistor. This simulates the FET and will lower the plate voltages of your preamp tubes. They are way high. Shoot for 200v on V1 and 220v on V2

5) The pre OD network must be 470k with 47pf bypass into 200k into 25k trim with 4.7k tail. THis is a lowgain network. Crank the trimmer and ONY ONLY ONLY use the amp in PAB boost mode. Adjust stack when in boost mode. Set the mids about 40% up, the bass about 45% up, and the treble up at about 30%

6) No snubbers on V2

7) HRM treble cap must be a 500pf (not the 330pf in the schematic)

8 ) Put a 5uf bypass cap on V1b. You need to slam the OD with bass and filter at the end.

Dogears,

Thanks very much for the input. It is really appreciated. My comments:

ad 1.) I have a 2k7 in there (did not have a 3k3).
ad 2.) I did have one - in my Bandmaster I do not - probably this cuts down gain quite a bit.
ad 3.) You mean in parallel with the 180k?
ad 5.) I used the 470K/47p network in my Bandmaster to cut down the gain but did not use the 25k-4k7 low gain network. I used a fixed divider (I have to check the values but I believe it was 150k/68k to ground).
ad 6.) Did not have any while it was HRM.
ad 7.) I had a 470p with a 39k slope resistor in the HRM.
ad 8.) I had a 1uF to cut down a little bass - it was rather muddy even with the 1uF.

Finally - I did not have a PAB in this amp, only a treble shift and a mid boost (insert 27k + 0.022uF between mid CCW and ground).

[Darkbluemurder]

[quote="dogears"]DBM,

I definately suggest swapping the 250ka pot out. Use the 100kb and a .01uf coupler. You need to maintain the "correct" RC network knee......

If you keep the 250ka pot, you could try upping the OD1 coupler from the HRM .0022 to a .0047 or .0056 cap. What is in it now??? If you use a .01 with a 250ka pot, you will get way way too much bass and the tone will not be nearly as nice as if you get the right knee frequency.

Glad the changes helped. Oh, did you run a 100k trimmer or voltage divider before the 1M OD master? If your HRM was correctly implemented, you would have gone straight into the 1M

Lastly, you should revisit the HRM at some point. You never got to hear it as Dumble designed it. Had you have, you might have kept it!


I ran a 100k over the 1MA Master. Without the 100k it was too harsh.

The OD 1 coupler is a 0.01uF right now. I believe I have a 100kA pot in my box to swap it for the 250kA.

What do you think for the 500p snubber caps? I read some prefer 350p or 250p. Probably good for humbuckers and maybe a bit bright for single coils.

[dogears]

First of all, I made a typo! I meant the 500pf bypasses the 220k V1B grid...... DOh....

I use a divider of 50k/50k before my 1M master. Simulates the OD level pot up half way.

500pf snubs may be atad too dark and compressed. Many of us are using something like 390pf with great success. Not too bright and not too muffled. I have a 250k pot and .001uf cap attached to the plate of V2B and going to ground. I like it set around 180k. Smooths it up a bunch. Mine is on a switch.

THing about HRM is that unless you run in PAB mode there is too much bass. It was designed for the PAB and for the lowgain network.

[Darkbluemurder]

First of all, I made a typo! I meant the 500pf bypasses the 220k V1B grid...... DOh....

I use a divider of 50k/50k before my 1M master. Simulates the OD level pot up half way.

500pf snubs may be atad too dark and compressed. Many of us are using something like 390pf with great success. Not too bright and not too muffled. I have a 250k pot and .001uf cap attached to the plate of V2B and going to ground. I like it set around 180k. Smooths it up a bunch. Mine is on a switch.

THing about HRM is that unless you run in PAB mode there is too much bass. It was designed for the PAB and for the lowgain network.

That is practical - I can just exchange the 390p I currently have in parallel with the V1b grid with one of the 500p snubbers.

I actually thought of installing a post OD tone control like this. In that case the basic sound could be brighter. I guess you are putting the cap before the pot to avoid DC on the pot and front panel.

[dogears]

Cap then pot or trimmer. Mine is a trimmer in the amp. Check out Gil's pics for the neat way to do it

You could just tweak and "ear" it. THen just attach a fixed network, preset if you will. Maybe run a switch to the back to toggle on and off. I like 150k to 180k as a reference.

First of all, I made a typo! I meant the 500pf bypasses the 220k V1B grid...... DOh....

I use a divider of 50k/50k before my 1M master. Simulates the OD level pot up half way.

500pf snubs may be atad too dark and compressed. Many of us are using something like 390pf with great success. Not too bright and not too muffled. I have a 250k pot and .001uf cap attached to the plate of V2B and going to ground. I like it set around 180k. Smooths it up a bunch. Mine is on a switch.

THing about HRM is that unless you run in PAB mode there is too much bass. It was designed for the PAB and for the lowgain network.

That is practical - I can just exchange the 390p I currently have in parallel with the V1b grid with one of the 500p snubbers.

I actually thought of installing a post OD tone control like this. In that case the basic sound could be brighter. I guess you are putting the cap before the pot to avoid DC on the pot and front panel.

[Darkbluemurder]

Finally I got it! Time to celebrate! Here's the rundown of what I did to my Fender Deluxe Reverb II:

First I separated the channels going from V1a+b (RP=100k, RK=1k5, CK 10uF) into both tone stacks. The clean has 250pf treble cap, 0.1uF bass cap, 0.022uF mid cap, 150k slope, fixed mid resistor 6k8. Pots are Treble 250kA, Bass 500kA push-pull w/Deep switch, Vol. 1MA push-pull with 100pF Bright. V2a (clean channel only) is RP=100k, RK=1k8, CK 4u7F. Coupling cap is 0.047uF.

The lead channel has the following: 330pf treble cap, 0.1 bass cap, 0.044 (two 0.022uF in parallel) mid cap (didn't have another 0.047), 120k slope (to be changed to 150k). Pots are 250kA Treble, 500kA Bass with .001 cap, 250kA Mid with Push-Pull to add a 820pF treble shift.
The rest is pretty much Hybrid Rev A with the following changes:
1. I removed the 390pF bypass cap on the 220k going into the 2nd stage (V2b). This was the key for me to get a smooth sound. The amp also appears to have more gain without the cap because there is a more focussed midrange. I did not try a 500p but I may in the near future just to see what it sounds like.
2. CK on the 2nd stage is 1uF instead of 4u7F to avoid muddiness. This was not as critical in my Concert. Coupling cap is 0.01uF instead of 0.047 uF.
3. No trim pot, instead I used 220k/56k as voltage divider. This simulates a 180k resistor going into a 100k trim turned up ca. 60%.
4. 3rd stage RP=180k, RK=2k7, CK=4u7F, Coupling Cap=0.02uF
5. 100kA Drive pot (dogears you were right it makes a huge difference compared to the 270k I had before)
6. 4th stage: RP=130k, RK=1k8, CK=4u7F, Coupling Cap=0.01uF, Level pot 250kA with 220k to ground. This should approximate a 150k into a 100k pot and works fine enough for me.
7. Snubber caps changed to 390 pF each from 500pF

The signal goes then into the reverb and then the PI. Dumble values except for the 0.005 input cap.

Now the amp does exactly what I expected. The clean sound is full and strong and the lead sound is creamy without being muddy. BTW I did a similar treatment to my Concert from the same era but went for the 70s values there.

I guess you folks knew this already but these amps are great platforms for cloning since they are point to point and still affordable. For me they are the thing since I can set up the clean and OD channels individually without compromising either.

Thanks for all your input - this saved a lot of trial and error.

DBM