Hiwatha build report!! Sound-samples included

[syndromet]

As some of you might have seen, I designed a circuit based on the Hiwatt Custom 50, as mentioned here. I decided to whoop this thing together, using the vero layout from the other post. I had a few startup problems, like wrong polarity PS filter cap and all transistors the wrong way. After fixing that, this thing came alive....

So, what does it sound like? It sounds like classic rock. The sound is rich and full, and it sounds like a maxed hiwatt. It has a great overdrive, and with the gain and vol turned all the way up it almost suiteable for heavy metal, using a humbucker equipped guitar. With single coils it is very sparkly and bluesy (think Gilmore).. It is very transperant for being so high gain, you will still hear the original guitar and it won't get mushy. It's also super-quiet. It sounds great!!!

I had a little trouble biasing this thing, as I started out with the typical 4,5V supply voltage. Twisting the trimpots, I found that the first transistor like a supplyvoltage at above 7V. If you build this, tune your trimpots by ear!

As I mentioned above, this thing sounds very, very good. There are, however, a few things I would like to change on it:

1. On my layout, all transistors are shown turned 180 degrees. The flat side on the transistor should be facing left. *FIXED*

2. On my layout, all pots are wired up the wrong way, meaning that they are reversed. I'll fix that a little later today. *FIXED*

3. It is a little bassy. I used all j201's and I guess using something like mpf102's would help this. You could also experiment with the capacitors at the switch.

4. 500K is to high for the gain and volume controll. I would guess 250k for gain and 100k for vol should be fine. *FIXED*

5. The last trimpot should have a higher value than 100k, as I'm having trouble biasing the last transistor correctly. I would guess a 250k should be more than enough *FIXED*

6. The presence controll needs some work, as it is barely notiseable like it is now.


Exept from the things mentioned above, the circuit and layout is verified.

So all in all, this is a great sounding circuit, among the best I have built yet. It still needs some work and a little fine-tuning, but it has potential of being a really, really good effect.

I'll post soundclipps later today.

Thanks to ROG, Sir H C, MartyMart, George Giblet, petemoore and anyone else who have helped me with this.

[syndromet]

Corrected schematic and layout:
Schematic
Layout

[MartyMart]

Nice one , glad that you've persued this one to the end !
Quick "tip"   RE: last Jfet bias :
Try reducing the 22k source resistor to around 4k7 , or try a 10k pot as a replacement.
I think that you'll get it much easier and be able to use a 100k trim pot ( depending on the J201 )
Gus has posted some interesting things and with reference to the new ROG Fetzer valve setup, I'm
going to be looking more closely at the IDSS and source resistor "bias" from now on .

MM.

[syndromet]

Nice one , glad that you've persued this one to the end !
Quick "tip"   RE: last Jfet bias :
Try reducing the 22k source resistor to around 4k7 , or try a 10k pot as a replacement.
I think that you'll get it much easier and be able to use a 100k trim pot ( depending on the J201 )
Gus has posted some interesting things and with reference to the new ROG Fetzer valve setup, I'm
going to be looking more closely at the IDSS and source resistor "bias" from now on .

MM.

Thanks for the tip. I'll try that later today. The bias of the last transistor isn't realy a problem. I think I have it fairly well biased, but the pot is cranced to one side. I'd like to see it pushing it a bit further would make a difference.

Anyone have a tip on the Presence controll? What could be done to make it more audiable?

[Cliff Schecht]

Tune it to the right frequency? What frequency(ies) is it effecting?

[syndromet]

Tune it to the right frequency? What frequency(ies) is it effecting?

I don't really know... I'm not good at this math thing, so I would appriciate if anyone could help me find that out..

[syndromet]

I promissed you guys soundclips, so here we go.
The first two clips is the Hiawatha with the J201 in the first gainstage. I found this to be a little to harsh, so I decided to swap it with a mpf102. Man, that helped!! The playing is awful this time, as I could not hear myself when recording. Just fooling around. The clips are recorded with Guitar->Hiawatha->Crappy soundcard, which unfortunately ad a little "ugliness" to the sound

So, tell me what you think.

J201 in the first stage:
Les Paul
Strat

MPF102 in first stage:
Strat
Les Paul

[fxdfxd]

OOpppps,

may I suggest you to fine tune your guitar ?
And you cannot have a good sound using this recording chain. I suggest you to use a software cab sim, you can find some for free, for example SIR, that is a free convolution plugin. Then you find some HP cab print (free too), the sound will be really better. We cannot really appreciate the sound when used without cabsim, is not natural enough :|

But, hey, thank for the samples

-fx

[syndromet]

OOpppps,

may I suggest you to fine tune your guitar ?
And you cannot have a good sound using this recording chain. I suggest you to use a software cab sim, you can find some for free, for example SIR, that is a free convolution plugin. Then you find some HP cab print (free too), the sound will be really better. We cannot really appreciate the sound when used without cabsim, is not natural enough :|

But, hey, thank for the samples

-fx

WOW! I didn't get to hear the samples before today, and you are absoloutly right. This sounds like s***!!! I have a lot of software cabsims on my computer, so I'll try to make some better samples to night. To anyone that listened to this, I'm sorry I put you through it.... 

[petemoore]

  ..just wondering...no cap DC decoupling between Q 2's D and 3's G ..where the 100k tone is?

[syndromet]

Seems like I forgot to add that DC-cap. Works well without it, though.I'll add it to the schematic later.

I ran the sound-samples through a Twin reverb with a 1*12 in Guitar rig, and it sounds a lot like the sound I'm getting from my amp.

j201 in first stage
Humbucker
Single coil

Mpf102 in fist stage
Single coil
Humbucker

[syndromet]

Double post....

[fxdfxd]

Hi

those samples sounds better, especially the second half of the J201+single coil sample.
But I can hear there is a problem with your FET biasing, it sounds too fuzzy, and act just like a noise gate at the end of the notes, that are the symptoms of a bad bias .
Maybe you can try to adjust the bias with a trim pot, and hear if there is still this kind of gate (do you know what I mean ? It acts just like the gate pot of the fuzz factory ?!?)

-fx

[syndromet]

Hi

those samples sounds better, especially the second half of the J201+single coil sample.
But I can hear there is a problem with your FET biasing, it sounds too fuzzy, and act just like a noise gate at the end of the notes, that are the symptoms of a bad bias .
Maybe you can try to adjust the bias with a trim pot, and hear if there is still this kind of gate (do you know what I mean ? It acts just like the gate pot of the fuzz factory ?!?)

-fx

Thanx for the healp, man.

Yeah, I noticed I had a bias problem too.  I have tried my best to get rid of it, but those 100k trimpots from futurlec are realy unpredictable. There is just a tiny area of the first trim that gives sound, and it's really hard to find the sweetspot. I've ordered a few more trimpots of another make, and see if that helps.

Using a j201, I only had sound when the drain read about 7V. This is kind of weird, in't it? Shoulden't the fet bias at around 4.5 V?

As mentioned in the first post of this tread, I also have some problems biasing the last transistor, and I havent had the time to fix it yet. I made the trimpot on the schem bigger, but I haven't had the chance to do anything about it on my board.

[fxdfxd]

Yeah, trimpots are hard to adjust.
Maybe you can use a real pot, sometimes it's easier ! And don"t read the voltage value, only your ears ! 

-fx

[rocket]

There are no artifacts as jgp creates

[syndromet]

There you go, a GIF version.

[fxdfxd]

hey Syndromet

do you know tinycad (http://tinycad.sourceforge.net/) ?
It's a nice software to draw schematics - opensource & free ! You should try It, instead of drawing all by yourself, you would gain a lot of time

-fx

[syndromet]

hey Syndromet

do you know tinycad (http://tinycad.sourceforge.net/) ?
It's a nice software to draw schematics - opensource & free ! You should try It, instead of drawing all by yourself, you would gain a lot of time

-fx

thanx! I've been looking for a program to do that! It takes up a LOT of time doing it the way using Paint and Photoshop, and its a PITA to edit....

[RaceDriver205]

Does seem to have a different 'edge' to it, this new distortion. A good 'edge' too.
Reminds me of the way the BSIAB had an 'edge'.