Author Topic: Way Huge pcb...  (Read 59415 times)

computerjones

Way Huge pcb...
« Reply #100 on: February 16, 2004, 06:45:34 PM »
you can also put single transistors into a socket instead of the chip, or chip + trans for mondo piggy back.  have fun!

idlefaction

Way Huge pcb...
« Reply #101 on: February 16, 2004, 07:00:28 PM »
heh, if i was doing another bmp i'd quite like to use piggybacked transistors.  i've always preferred the sound of a bmp with lower gain transistors.  i wish i could quantify why.

perhaps 'dead bug' styling two of those xistor array chips, and using surface mount 5k6 resistors between the legs for the piggy resistors...  *grin*
Darren
NZ

computerjones

Way Huge pcb...
« Reply #102 on: February 16, 2004, 07:03:23 PM »
you could piggyback 2 of these chips, one on each side of the board....

idlefaction

Way Huge pcb...
« Reply #103 on: February 16, 2004, 07:07:30 PM »
cj, did you see the wicked thread a while back on piggybacking transistors?  it was quite interesting:

http://www.diystompboxes.com/sboxforum/viewtopic.php?t=17513
Darren
NZ

petemoore

Yes
« Reply #104 on: February 16, 2004, 07:19:00 PM »
I have 3 [or is it four now] Stompboxes with pig technology in them.
  Having pigs in your box IS a good thing.
  EZ for me to tag an R [small 1k-10k] on an emitter and flatten the scheize out of bottom of the leads and scrunch two leads into one socket hole...I use the sharp knife or chisel to 'grab' the lead right next to the socket and push it in.
Convention creates following, following creates convention.

Skreddy

Re: low-gain transistors in BMPs...
« Reply #105 on: February 16, 2004, 09:45:39 PM »
I'll give you all the benefit of my knowlege gained by lots of subbing in search of the magic of the original triangle-knob version...

The magic number is 35.  Choose transistors with a minimum gain of (exactly) 35, and you'll find that balance between articulation & touch-sensitivity and creaminess and hair that the circa 1971 models had.  

On the other hand...

You can get really very nice results by using a common 2N5088 in the #1 position and common germanium NPNs (NTE101) in positions 2 and 3 (clipping), then decide which you like best in the tone-recovery/output stage.

Re: Tone stack values... I think the mid notch of the Pickle probably sounds great in the middle position, but I bet it sounds way too dark in the bass direction.  A toggle or an AMZ 'mid' control would be cool.  I kinda like the old BMP's values of .004uf / 33k on the treble side and 33k / .01uf on the bass side.  Sounds very much like a speaker emulation to me, with lots of useable settings all around.

bobbletrox

Way Huge pcb...
« Reply #106 on: February 16, 2004, 10:15:38 PM »
Will replacing transistors with an array become known as "pulling a Way Huge"?  :o

I didn't know those ICs even existed before this thread...are there 8-pin 2 transistor versions too?

Mr.Huge

YES
« Reply #107 on: February 16, 2004, 10:30:47 PM »
Yes there is a Santa... Dual Transistor Array:
http://www.analog.com/UploadedFiles/Data_Sheets/410572853MAT02_e.pdf

I'm sure there are others.

http://www.national.com/ds/LM/LM194.pdf

The LM394 is what is used in discrete op-amps like the 990.

http://www.johnhardyco.com/pdf/990.pdf

-Mr. Huge
BEN:   Mos Eisley Spaceport. You will never find a more wretched hive of scum and villainy. We must be cautious.

LUKE:   But I was going into Toshi Station to pick up some power converters...

VADER:   I find your lack of faith disturbing.

bobbletrox

Way Huge pcb...
« Reply #108 on: February 16, 2004, 10:45:01 PM »
Great!  The LM394N looks definitly worth checking out.

Thanks Jeorge.

idlefaction

Way Huge pcb...
« Reply #109 on: February 16, 2004, 10:48:19 PM »
Skreddy - heh, you can use two 2N3904's piggied with an emitter resistor of about 820 ohms to get a gain of 35.  it's different for every pair of Q's, but there ya go.  :)
Darren
NZ

Fret Wire

Way Huge pcb...
« Reply #110 on: February 16, 2004, 11:28:28 PM »
Pete, is this what you're looking for? Found it on Mouser

http://www.nteinc.com/specs/2300to2399/pdf/nte2321.pdf
Fret Wire
(Keyser Soze)

petemoore

Yupp..that's it !!!
« Reply #111 on: February 17, 2004, 05:51:56 AM »
Thanks !!!
  I don't know why not...the NTE site may be down...the page that did come up looked different.
  Yes much easier to work with an active component when the pinout is verified...lol.
  Pretty easy to remem...just pick a corner...there's a collector...the two middle pins dont connect...emitters toward the middle...CBE...no problem !!!
  I paid like 3$ for the thing...so I'll be using it for something !!
Convention creates following, following creates convention.

petemoore

Triple Passivation !!!
« Reply #112 on: February 17, 2004, 06:36:40 AM »
And exclusive Silicon Nitride !!!
  Interesting, the dual chip seems to boast low noise [I'm sure there's a low noise quad] ..may be just the  thing for a BMP...
Convention creates following, following creates convention.

bobbletrox

Way Huge pcb...
« Reply #113 on: February 17, 2004, 07:30:04 AM »
...and these arrays can replace transistors like 2N5088s ect without any further tweaking to the circuit?  :?

petemoore

Bm Q gains...
« Reply #114 on: February 17, 2004, 07:46:30 AM »
Im seeing 5089s and 5088's specified for the BM ckt.
  The Quad pack I have here only specifies Hfe as 100 min...
  Perhaps I use the plug/socket I made from a piece of perf, three R leads, and three holes of an IC socket...and see hwhat the meter says about these Q's in 14 pin package...
Convention creates following, following creates convention.

Jason Stout

Way Huge pcb...
« Reply #115 on: February 17, 2004, 09:19:42 AM »
I wish matched jfet arrays were made.....  :(
Jason Stout

Jay Doyle

  • Guest
Way Huge pcb...
« Reply #116 on: February 17, 2004, 09:27:44 AM »
I've used the CA3086 in discrete op amp designs. It's great to use when making a discrete OTA.

MR COFFEE

Low-noise Quad tranny - but forget the DIP business!
« Reply #117 on: February 17, 2004, 09:44:21 AM »
MAT-04 from Analog Devices is a low noise, but pricey, Quad NPN Array in a 14-pin DIP. They are more expensive because they are large geometry transistors fabricated in a low noise process and they are all matched closely for use in circuits where matching is critical - log converters, multiple matched current mirrors, differential amps, VCAs made of discrete transistors, etc.

BUT, the advantage to a DIYer of using the DIP-packaged transistors in a BMP is nil compared to discrete trannys.

The only advantage conveyed by the DIP array to Way Huge was to save time/cost in assembly, or possibly to discourage less-persistent and savvy reverse engineers than the crew here 8) , as RG suggested). Or perhaps some anxiety that Mike Matthews might have a beef with him for cloning :?: Who knows, Jeorge isn't saying. :cry:  :wink:

People who seek status or to increase the draw of their studio "arsenal" blow lots of money on expensive and aging FX with "legendary reputations" they've probably never had a chance to hear before they plunk down the big bucks - all the money and secretiveness gives them a bigger draw than if the truth be known that some "legendary" boutique pedal is simply a (hopefully well-made) clone of an old standard.

I would rather collaborate with all the cool people that hang out here and listen and tweak away until I hear something really good, that still trips my trigger when I listen and A-B compare it with the "original" circuit 4 days later.

And I thank the dear Lord for the genius who invented that white plug-in breadboard stuff!
Bart

Jay Doyle

  • Guest
Way Huge pcb...
« Reply #118 on: February 17, 2004, 09:58:44 AM »
Here is the datasheet for the 3086

Skreddy

Hint Hint
« Reply #119 on: February 17, 2004, 02:54:36 PM »
Re: datasheet for the 3086...
"The CA3086 consists of five general-purpose silicon NPN
transistors on a common monolithic substrate. Two of the
transistors are internally connected to form a differentially
connected pair."

Perfect for making an octave-up pedal!

One gain stage -> differential pair driving ge diodes in series -> clipping stage -> tonestack / recovery / output stage.  

I'm off to schematic/layout land...