hmmm Rangemaster blues

[knealebrown]

http://www.aronnelson.com/gallery/main.php/v/album26/Rangemaster.gif.html

can someone check this vero layout for me please it says verified but i swear i cant have built it wrong its so simple 

heres the schematic

http://www.google.co.uk/imgres?imgurl=http://fuzzcentral.ssguitar.com/rangemaster/rangemasterschematic.gif&imgrefurl=http://fuzzcentral.ssguitar.com/rangemaster.php&usg=__bJvPkHe7QBqknaSif05Kp-t-iAE=&h=191&w=292&sz=4&hl=en&start=1&um=1&itbs=1&tbnid=BGMcZRPpeWlzhM:&tbnh=75&tbnw=115&prev=/images%3Fq%3Drangemaster%2Bschematic%26um%3D1%26hl%3Den%26safe%3Doff%26sa%3DN%26tbs%3Disch:1

i honestly dont know what i could have done wrong. Im using a ac128 as the transistor will that change things?

Thanks in advance

[Hides-His-Eyes]

??

[knealebrown]

Yeah I seem to have gotcthe pin out right then. Christ

[Scruffie]

Did you adjust the bias? You need to change the values of the 68k & 3k9 to suit your Transistor... Read R.G Keens article on the technology of the Rangemaster.

Also... if it's the same as the schematic you linked to, the pot is backwards, otherwise seems okay.

[knealebrown]

what do you mean backwards? should it read 231 (top to bottom) on the vero layout?

[Scruffie]

what do you mean backwards? should it read 231 (top to bottom) on the vero layout?

Nah I mean 1&3 are swapped, so it'd work in reverse.
3,1,2... it's not important anyway.

[knealebrown]

tried the pot change but got no change. i cant belive im getting stumped by this 

[Scruffie]

tried the pot change but got no change. i cant belive im getting stumped by this  

Nah as I said it's not important to change the pot, it'll just work in the opposite direction, the Bias is the thing you need to check, have you changed the bias? What's the Voltage at the Collector of the Transistor? Does the Transistor even work?

[Brymus]

Also a Ge diode across the pins will help if the transister is leaky.
Using pots like RG suggests in his rangemaster PDF is a good idea to get the bias right like already mentioned.

[knealebrown]

yeah im reading through that now. thanks for the tips 

[sundgist]

Heres a verified vero layout I made a few years ago. I put trimmers on board to replace the 3.9k and 68k.
There are hidden trace cuts at C4,C7,C9,D7,E7. Hard to see on the layout.
I've included an input cap switch. My switch is wired off-board but shown on-board for tidyness.
One 'on' position gives 5.68nF which is near the stock 5nF. The other 'on' position gives 1.68nF and 'off' gives 680pF.
Did it this way as I wanted more degrees of bass cut. Works OK other than the 680pF setting being barely at unity.
I built mine with an ac128 and have never been really happy with it. Doesn't seem to have enough gain. Probably due to the tranny.

Also a Ge diode across the pins will help if the transister is leaky.

How does this work? and across which pins?
Mine are leaky. Will this improve the gain?

I wouldn't mind getting this working properly.

I've edited this post about 4 times now. I've just realised what a %^&*up I've made of my build now I've looked at it after all this time.
The layout is correct. My build is wrong and I'm a moron. I'll post tomorrow once I get a minute to fix this.

[zombiwoof]

This is a little off topic, but does anyone know what happened to Fuzz Central?.  You can still find the individual pages, but the website seems to be gone now.  Did he just give up on it?

Al

[Scruffie]

This is a little off topic, but does anyone know what happened to Fuzz Central?.  You can still find the individual pages, but the website seems to be gone now.  Did he just give up on it?

Al

I think he's just been having hosting problems like when he got infected with that virus... I dunno who runs it though or wether they might be too busy to keep hosting it but considering the rest of it's there, guess it's just a hosting issue.

Here's a layout I did for the Dallas Rangemaster W/ Onboard Pot & Trimmers on Board, not verified but I think it's okay, if you don't want to make the input caps switchable, just put the input to the Switch Lug A or C points on the board and remove the other cap not being used.

[newfish]

Is the AC-128 an NPN device?

The layout using an OC44 will be positive ground.

* EDIT *

It's a negative ground layout - just looked...

[Scruffie]

Is the AC-128 an NPN device?

The layout using an OC44 will be positive ground.

* EDIT *

It's a negative ground layout - just looked...

128s are PNP

Maybe being Negative ground is causing the Issue... circuits don't like that, build it Positive ground and use a battery or a Bipolar Supply from a Chip.

[flintstoned]

Ugh, thanks a lot sundgist. never thought of all the places on the internet I've been, that the first time I'd see a pic of two trannies humping would be on this site!

Not that there's anything wrong with that...

[sundgist]

Ugh, thanks a lot sundgist. never thought of all the places on the internet I've been, that the first time I'd see a pic of two trannies humping would be on this site!

Not that there's anything wrong with that...

I tipped a bag of components out onto the bench and  thats how they landed!  no lie 

I've edited this post about 4 times now. I've just realised what a %^&*up I've made of my build now I've looked at it after all this time.
The layout is correct. My build is wrong and I'm a moron. I'll post tomorrow once I get a minute to fix this.

After 2 years my rangemaster now works. Biased up using the trims and sounds like most of the soundclips I've come across.
The higher bass cut switching options cause a lot of volume reduction but I can live with that.

Also a Ge diode across the pins will help if the transister is leaky.

Is this where you place an inverse biased Ge diode across the base/emitter to cancel out effects of temperature?
Like so, in the case of a pnp device.
              -->¦--
C -->¦--B--¦<--E

i honestly dont know what i could have done wrong. Im using a ac128 as the transistor will that change things?

Good luck, hope you don't take as long as me to get it working.