need help getting a strat to work

[wjdunham]

I realize this has been discussed A LOT in this forum, I have tried to search for the appropriate terms and read as much as I could. I don't want to rehash things, but I'm still having trouble figuring out what my next steps should be given my problem, too many choices. A small bit of background, I have two D style amps, a 100W #124 that I'm really happy with when I use my double coil equipped guitars. I also built a "tweaked" DLite and that's what I'm in the process of trying to get to sound good with a strat.

Here's my problem - OD channel is undefined and/or muddy. Single notes sound OK through most of the range, but chords are all mud. Also, bridge pickup is thin and too trebbly sounding. Ideally I'd like it to sound like my 100W does with the LP, since I use the strat way more at gigs. Not sure if that's even possible. The clean channel sounds very good and I'd like to not upset that too much.

Here's what I have so far - started with the tweaked DLite schematic and layout, 220K/150K on both plates. I raised the voltages in the preamp to 205/210 on V1 and 210-215 on V2 - Tony or Henry or both suggested that this might tighten up the bass and restore some sparkle with the high plate load resistors. I changed the mid cap to .047 and slope to 100K. This made the clean channel very full and sweet with the single coils.

I still have the .002 treble cap with the mid boost switch, the amp is hard wired in rock mode. mid and treble pots are 250KB, bass is 500kA with the .001 bypass. I have a 30pf master bypass cap, and the OD bass filter entrance mod and an OD treble bleed as well.

My next step was going to be to change the treble cap back to 330pf, and change the mid boost to the early 80s deep switch (I would then have the full early 80s tone stack with a 100k slope resistor). If that doesn't have a major impact them I'm a bit at a loss as to what the next step should be. I've played with the OD trim, I have to keep it about mid-way (around 48K ohms) to get a good amount of drive (drive control set to 4 or 5) with the weaker single coil pickups when the PAB is off. I realize this is a bit high, but lowering it doesn't seem to cure the mid range mud either. I've thought about changing to all 100K plate resistors, but that may be a sideways step. Any suggestions would be greatly appreciated.

by the way, here's the tone I'm after - (I probably need a hand transplant to even get close)... Great definition with mostly the neck pickup.

http://www.youtube.com/watch?v=VwGHaKbnoL8

Bill

[Structo]

Mullets rule!

[wjdunham]

Wow - that's the fastest thread derail I've seen in a while this thing's already off the tracks...

[talbany]

.047 mid can make for a muddy OD.. Been there....Might be better suited on 100k amp.....First thing to try is some different preamp tubes in the OD spot... I recommend a newer higher gain midrange friendly tube like JJ or TAD or Mullard reissue whatever.. Older NOS or pulls get loose on the lowend especially with the 220/150. See if that gets you part of the way out of the woods.. I'll do this before I start changing componets..Sometimes if you can find the magic tube in that spot minor tweakage maybe all you need..Some minor tweaks in OD that should help bring out some mids are lowering the 150k resistor entrance to the OD level pot to 100k..(This doesn't mess with the knee just changes the frequency responce) You can also lower the tail resistor of the OD entrance pot..Also make sure your bypass caps are of good quality w/fairly low ESR...In my travels I've never found the need for the treble bleed ntwrk on a 220k amp...Could you post a layout or schematic...not too familier with the D-Lite w/Mods...Hope this helps..

Not really a fan of the OD entrance cap.. Extra caps, resistors suck tone and change the breakup character in OD..Just me...Weirdo!!

Can you put a pair of KT-88's on D-Lite Call it a D-Heavy.. Put me down 1


Tony VVT

[butwhatif]

Adjust the od trimmer down to around 25k, change the od2 out cap from .005 to .01 or .02 . try 470k entrance to trimmer, total w/ no input cap. use 100k lin od master pot

[greiswig]

Can you put a pair of KT-88's on D-Lite Call it a D-Heavy.. Put me down 1


Tony VVT

Running a pair of '88s in my D'Lite. Like 'em.

[Structo]

Wow - that's the fastest thread derail I've seen in a while this thing's already off the tracks...

Sorry I couldn't resist.

Sometimes us nerdy, tube head types, need a little levity injected into our lives.
I will try to restrain myself in the future.

[ER]

Don't forget to optimize the input resistor, if you have an impedance missmatch with your pickups you won't get it back later. Most fender amps use 68k, not 22k.

-er

[greiswig]

Don't forget to optimize the input resistor, if you have an impedance missmatch with your pickups you won't get it back later. Most fender amps use 68k, not 22k.

-er

Interesting. I haven't heard much about the effects of this resistor or the difference between the two values you describe. Care to elaborate?

-g

[talbany]

Interesting. I haven't heard much about the effects of this resistor or the difference between the two values you describe. Care to elaborate?

The input grid resister accomplishes several effects.. One is to help block RF from entering the grid..( Nigel could have used one on his Marshall)..They act as a very high frequency low-pass filter in conjunction with the input capacitance of the triode...which is the sum of the grid-to-cathode capacitance and the Miller capacitance, and can get as high as 100pF or more..Adding a resistor in a series configuration like grid resistors does change the impedance and we all know impedance is frequency dependent however the function of a grid resistor is not to change the impedance..It's mainly used as a crude high frequency low pass filter and RF blocker..The only resistors that I would refuer to as an impedance shift would be the 100k/150k resistors before the Drive and level pots since there function is to change/alter frequency response only...By the way want to increase the bandwidth lower the resistor like D did..Sorry can't say his name...


Tony VVT

[wjdunham]

I did make some great progress over the weekend. Funny enough, I had just "upgraded" to some some old RCA black (long) plate 12ax7's which may have contributed to the problem. I put the EH back in the V2 spot, left the RCA in V1, left the EH in the PI as well. I changed the slope R back to 150K, removed the OD entrance filter, lowered the V1 and V2 plate voltages a little, and tried some different mid-cap values and put 10uF bypass on both V1s. I still don't hear a lot of difference between mid cap values from .01 to .047, but the muddiness is definitely gone. It sounds good with LP AND strat, single note leads with the strat bridge pickup are still a little thin, but chords are nice crunchy and crisp with all pickups. Clean channel is still very nice.

I'm still going to try removing the 150K resistor before the OD Ratio and change that pot to 250KB. It's easy enough to try a higher input resistor, I may play with that, but I'm not having a high frequency rolloff which I would think would be a problem if there's a big mismatch between guitar in and amp input? Thanks for all the suggestions.

Tom, you don't happen to have a mullet do you
Bill

[butwhatif]

I'm still going to try removing the 150K resistor before the OD Ratio and change that pot to 250KB.


Don't think that will make u happy, but not hard to try. Did u try a .02 in place of the .005 od output cap, it will give you a more solid tone-- but use the 100k L pot--

[greiswig]

..It's mainly used as a crude high frequency low pass filter and RF blocker..

Why would we want to block Robben Ford from using our amp?

The only resistors that I would refuer to as an impedance shift would be the 100k/150k resistors before the Drive and level pots since there function is to change/alter frequency response only...By the way want to increase the bandwidth lower the resistor like D did..Sorry can't say his name...


Tony VVT

The one whose name cannot be spoken. Seriously, thanks, Tony...good explanation.

-g

[wjdunham]

I ran out of .01 and .02 caps, waiting for my order from Mouser, should be able to try that later this week.

[M Fowler]

What about the B+1 filter stage is the capitance the right value or increased to provide more filtering which can cause muddiness, too much bass.