Diefet with Tillman guitar Preamp choking sound HELP

[askwho69]

Hello All i have a problem now that i dont have before eheheh

* my main dist is Diefet "Diezel Amp  Sim" the sound is cool and I dont have a problem with it i liked it and friends like it too.
* the problem starts when i installed Tillman Preamp on my guitar after the volume Pot "500k" the problem is when i switch on the tillman my Diefet sounds Farted and unbias sounds like crap... but when i switch ok its ok.. also when i use other dist i have its ok and have no problem with it. the only problem is with Diefet and Tillman Turned on..

Any ideas why is this happening?

Diefet
Tillman



Thanks for viewing

[J0K3RX]

Might have to re-bias the Diefet for use with the Tillman? Looks like you are almost adding another stage to the Diefet when using the Tillman...?

Or, maybe because you are running a preamp into a preamp?

[Earthscum]

I can only think of 2 things... First, you do have a cap decoupling the tillman from the diefet, right If not then the tillman will try to bias the df first stage gate way above ground. Fart o rama.
Second is how does the diefet sound when you put something else between it and the guitar like a buffer

[Richard6]

What does it do when you lower the guitar volume level? Have you tried reducing the gain on the Diefet? I had trouble with noise when I ran a Timmman into a Dr Boogey.

[Gurner]

Maybe it's because I've has a few too many tinnies tonight (nice weather in London) ...or maybe it's becuase I'm not overly familiar with the MAX1044...but if I'm reading the MAX1044 datasheet correctly (& there's a good chance I'm not!), if you're wanting to dounble you input voltage, shouldn't your MAX1044 implementation look like figure 9 in the Maxim datasheet....  http://datasheets.maxim-ic.com/en/ds/ICL7660-MAX1044.pdf (straight off the bat, pin 1 is different in their diagram)

Also, I'm left wondering if your current draw is too much for the MAX1044 to supply?

[askwho69]

Might have to re-bias the Diefet for use with the Tillman? Looks like you are almost adding another stage to the Diefet when using the Tillman...?

Or, maybe because you are running a preamp into a preamp?

this is the first thing in my mind... but the diefet is ok and biased well without tillman it's sound awesome... also when i tried to insert ISP Deciminator Clone before diefet it has same Effect FART even low gain. Picking dynamic become very low attack.

I can only think of 2 things... First, you do have a cap decoupling the tillman from the diefet, right If not then the tillman will try to bias the df first stage gate way above ground. Fart o rama.
Second is how does the diefet sound when you put something else between it and the guitar like a buffer

which cap can I insert and which part? is it the output of the tillman? like .1uf? I remember a while ago when I built Thor and tonemender im connecting the 2 effects so i ask some of our forum expert about taking the 100n output cap of the Thor before the volume and it has unbias sound .
Also the problem of the diefet when boosting with TS alike if the volume of TS is not full the Diefet sounds unclear and has some noise on it... what make the Diefet so sensitive? is it the Diode on the First Jfet?

What does it do when you lower the guitar volume level? Have you tried reducing the gain on the Diefet? I had trouble with noise when I ran a Timmman into a Dr Boogey.

even lower gain its same sound Ive heard unbiase , Fart, late picking dynamic, and it will sound only if I strum it hard.

Maybe it's because I've has a few too many tinnies tonight (nice weather in London) ...or maybe it's becuase I'm not overly familiar with the MAX1044...but if I'm reading the MAX1044 datasheet correctly (& there's a good chance I'm not!), if you're wanting to dounble you input voltage, shouldn't your MAX1044 implementation look like figure 9 in the Maxim datasheet....  http://datasheets.maxim-ic.com/en/ds/ICL7660-MAX1044.pdf (straight off the bat, pin 1 is different in their diagram)

Also, I'm left wondering if your current draw is too much for the MAX1044 to supply?

MAX1044 is a voltage divider i dont have a problem using Diefet alone but the problem occur when tillman preamp is on.


THANKS For the Reply guys Hope i can solve this

[askwho69]

Ok I'd try bias the Tillman to 4.5 D and the fart is gone but still bad sounding hahayz...  

[WGTP]

I've noticed that when I drive j201 stages too hard they sort of choke out.  Try a 100k resistor between the preamp and the first stage and see if that helps. 

[amptramp]

You may be getting some sort of gulp distortion where the relatively low impedance of the Tillman output can pull the gate of the first DieFET stage into conduction by forward-biasing the gate-source junction.  This pulls current in a direction that shuts off Q1 on the DieFET as soon as the signal starts to go negative.  Deleting C16 on the DieFET may help.

[Earthscum]

egads... if you still have the 51k at the end of the tillman, you could try pulling it out. I wonder if that is an issue?

After looking at the thing, you could pull R4 and replace the 4.7u cap with something like 0 .1u in the Tillman section.

Replace R1 (1M) with a pot (100k-1M should be fine, 1M is a good bet). This will allow you to lower the volume through the voltage divider, and it still keeps the gate of the (first diefet stage) held at ground where it wants to be. This will allow you to keep C16 in place so you still have the maximum gain available if needed. If you feel like you have to turn it down, but you lose your highs, tie a smallish cap (experiment here) from the top of that 1M(?) pot to the wiper to pass the highs.

[askwho69]

I've noticed that when I drive j201 stages too hard they sort of choke out.  Try a 100k resistor between the preamp and the first stage and see if that helps. 

Thanks for your reply i'll try this one

You may be getting some sort of gulp distortion where the relatively low impedance of the Tillman output can pull the gate of the first DieFET stage into conduction by forward-biasing the gate-source junction.  This pulls current in a direction that shuts off Q1 on the DieFET as soon as the signal starts to go negative.  Deleting C16 on the DieFET may help.

mmh deleting the 1uf gonna try it too... but can i loose some highs or gain omitting this one?

egads... if you still have the 51k at the end of the tillman, you could try pulling it out. I wonder if that is an issue?

After looking at the thing, you could pull R4 and replace the 4.7u cap with something like 0 .1u in the Tillman section.

Replace R1 (1M) with a pot (100k-1M should be fine, 1M is a good bet). This will allow you to lower the volume through the voltage divider, and it still keeps the gate of the (first diefet stage) held at ground where it wants to be. This will allow you to keep C16 in place so you still have the maximum gain available if needed. If you feel like you have to turn it down, but you lose your highs, tie a smallish cap (experiment here) from the top of that 1M(?) pot to the wiper to pass the highs.

Maybe the 51k ? gonna try this also .. maybe diefet needs to be boost for volume, that's what I encounter in TS boosting DieFet in half volume it has some kind of noise I heard .

Ok replacing the 1M to pot so that i can dial the volume and retain the 1uf C16

Thanks all gonna report back after omitting some components and replacing

A2

[Earthscum]

You may still try pulling up a leg of the 1u, as per Ron's suggestion, and see what kind of range that gives you. Some circuits react differently to buffers vs. guitar (although Fet circuits usually don't follow this rule so much due to the high input impedance).

The last thing I can think of is that the input of the diefet is reacting differently to the tillman. If nothing else gets you close, try removing diefet's C1, and C21 (or, just lift a leg of each cap) and a quick jumper across R1 (68k). This will get rid of the input filtering network of the Diefet and you can see if that is reacting badly with the Till for some reason. Try it out with and without R1 (jumpered). Each time you change 1 thing, may as well give it a shot and see if it helps so you know where to turn back aroudn. GL!

[askwho69]

You may still try pulling up a leg of the 1u, as per Ron's suggestion, and see what kind of range that gives you. Some circuits react differently to buffers vs. guitar (although Fet circuits usually don't follow this rule so much due to the high input impedance).

The last thing I can think of is that the input of the diefet is reacting differently to the tillman. If nothing else gets you close, try removing diefet's C1, and C21 (or, just lift a leg of each cap) and a quick jumper across R1 (68k). This will get rid of the input filtering network of the Diefet and you can see if that is reacting badly with the Till for some reason. Try it out with and without R1 (jumpered). Each time you change 1 thing, may as well give it a shot and see if it helps so you know where to turn back aroudn. GL!

i tried pulling the 51k of the tillman and it's not choking sound but fuzzy maybe because of too much gain pushing by tillman, gonna try what you suggest but what if i use diefet alone its gonna change some? tillman is for boosting/pushing/solo .. mhh gonna sacrifice some tone on this one... tillman sounds so awesome on clean and also for boosting GT2/OD "opamp" its sounds creamy and warm..

What if im gonna make Klon buffer infront of the diefet? i try Guitar > TS"on" > Diefet  > amp its sound ok maybe Jfet preamp + Jfet highgain preamp is a mess .. can u advice making a buffer in front of DiefEt?

Thanks for your time mate

[askwho69]

Hello Again i think i figured it out hahahah im so stupid reversing the polarity of 4.7uf  I gave up before but after seeing the layout of mine again i saw i reversed it  now its working perfectly . . .  thanks for the help mates