Search found 163 matches

by cpm
21 Jan 2010, 11:01
Forum: Resistors & Potentiometers
Topic: Volume Limiting Resistor?
Replies: 3
Views: 3944

Re: Volume Limiting Resistor?

have you checked the pot is NOT linear?

if not, i wuld go for the voltage divider too, but take account about the impedance if it may be an issue.
Better would be to attenuate bofore an active stage, (e.g. output buffer, etc). Without details on the circuit we cant go into more detail-
by cpm
04 Jan 2010, 08:35
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: EHX - Electric Mistress Flanger [schematic]
Replies: 55
Views: 28917

Re: Late 70s EH Electric Mistress Flanger [schematic]

I have worked on a later (non-curved traces) model, but still the same circuit (just some extra filter caps)
I used the schematic for the EM18v that can be found on the net to follow the circuit without any problem.
by cpm
16 Dec 2009, 14:31
Forum: Transistors
Topic: New member and "stupid" question about Fuzz Face trannies
Replies: 31
Views: 21870

Re: New member and "stupid" question about Fuzz Face trannies

bienvenido Proco I advise you build first a fuzz using Si- transistors. Usually whatever NPN (or pnp if needed) can sound nice and some like the 2N3904 can be found easily and real cheap. Si transistors can be made to sound close to Ge. Only theres need for different circuit design because the impe...
by cpm
12 Dec 2009, 20:15
Forum: ICs (Integrated Circuits)
Topic: IC for 24v operation
Replies: 5
Views: 3961

Re: IC for 24v operation

what difference can 9v or 24v make anyway? its a buffer, as long as your input is within headroom.

for an IC, the usual TL072 and most other opamps are rated up to 36V
by cpm
28 Nov 2009, 19:31
Forum: Boutique Stompboxes dissected...
Topic: FET Dream
Replies: 9
Views: 3699

Re: FET Dream

so much blah... to sell only one pedal.
by cpm
26 Nov 2009, 05:09
Forum: Lords of the Boards - Vero, Perf, PCB or Point-to-Point
Topic: Eagle Trace size
Replies: 3
Views: 10255

Re: Eagle Trace size

impedance

...and coolness, yeah
by cpm
16 Nov 2009, 17:49
Forum: Boutique Stompboxes dissected...
Topic: Henretta Engineering - Choad Blaster
Replies: 38
Views: 8732

Re: Henretta Engineering - Choad Blaster

looks like a simple circuit for a double sided board (vias, thin traces..., autoroute abuse?)
by cpm
05 Nov 2009, 14:11
Forum: Amplifiers
Topic: less volume from a fender amp - pot in a box?
Replies: 5
Views: 2146

Re: less volume from a fender amp - pot in a box?

why dont simply say it's a volume pot placed in the loop? No need for two pages of BS
by cpm
05 Nov 2009, 13:29
Forum: Boutique Stompboxes dissected...
Topic: Puretube's Tube Space Vibwahto - gut shots
Replies: 18
Views: 7091

Re: Puretube's Tube Space Vibwahto - gut shots

anyone repost the images from the browser cahce?
by cpm
02 Nov 2009, 13:29
Forum: Boutique Stompboxes dissected...
Topic: Home Brew Electronics - Mimic Delay MockII
Replies: 4
Views: 1539

Re: HBE - Mimic Delay MockII

also, the filters are implemented with bjt transistors, which catch easily noise on the power line i would try to break the ground paths from (and the power if necessary) the oscillator area and wire it directly to the power jack. or maybe there is not enough filtering for that clock frequency... at...
by cpm
01 Nov 2009, 13:49
Forum: ICs (Integrated Circuits)
Topic: Why don't we use 555 for voltage doubling/negative voltages?
Replies: 7
Views: 9154

Re: Why don't we use 555 for voltage doubling/negative voltages?

i have tried a charge pump with the 555.
it worked fine but it was short of current output for my project, neither was a max1044, so i guess both implementations are at the same level (i finally used lt1054)
by cpm
30 Oct 2009, 13:14
Forum: Boutique Stompboxes dissected...
Topic: Toneczar - Openhaus [traced]
Replies: 365
Views: 162776

Re: Toneczar Openhaus [gutshots and schematic] [traced]

wow
6 opamps for tone shapping, isn't that a little overkill?
by cpm
29 Oct 2009, 05:10
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Boss - CE-3 Chorus Ensemble [schematic]
Replies: 41
Views: 47325

Re: Boss CE-3 Chorus [schematic]

rocklander wrote: nice.. that mod would make it more usable for me at least.. thanks :applause:
locate the (-) connection on the board from the DC jack. the pad right besides it is GND (fro the battery), so just put a small jumper.
by cpm
27 Oct 2009, 10:36
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Boss - CE-3 Chorus Ensemble [schematic]
Replies: 41
Views: 47325

Re: Boss CE-3 Chorus [schematic]

i got one CE3 in for minor work: lifting the diode to ground, the power supply issue with early adapters

the fact is i liked how it sounds, so i bought one cheap off ebay, it on its way right now.
by cpm
21 Oct 2009, 08:45
Forum: Boutique Stompboxes dissected...
Topic: Schumann - PLL
Replies: 88
Views: 23102

Re: Schumann - PLL

... Look what's going on with this thing - it uses a Phase-Locked Loop to track an input signal and have the oscillators match the pitch. But it's not done very well, so it tracks extremely poorly and sounds all "crazy" ... the main point in these kind of effects is the reliable tracking ...
by cpm
08 Oct 2009, 13:28
Forum: Boutique Stompboxes dissected...
Topic: Schumann Lion X
Replies: 53
Views: 14216

Re: Schumann Lion X

this is a nightmare :whappen:
its bound to fail and dont believe even the guy himsef could repair it.
by cpm
07 Oct 2009, 06:56
Forum: Modern Stompbox Effects (1975 - ...)
Topic: EHX - Big Muff Pi 2007 [schematic]
Replies: 34
Views: 24872

Re: EHX Big Muff, EC3003 REV_C Model [schematic]

i dindnt have much problems when soldering on the board, not great quality, but not terrible.

some 1uFs must be changed into 100n definitely.
those 2 100R+220uF filters dc nicely
by cpm
02 Oct 2009, 07:00
Forum: ICs (Integrated Circuits)
Topic: Substitute SAD1024 for MN3007
Replies: 1
Views: 3525

Re: Substitute SAD1024 for MN3007

Well, I have seen people substitute it a couple of times (an old Electro Harmonix Small Clone schem, if I am not wrong, and the folks at Moosapotamus, on their A/DA Flanger), theres a lot of information on those, read all the related therads at diystompboxes where you will find all the answers. A f...
by cpm
25 Sep 2009, 10:26
Forum: Pimp-My-Cheap-Pedal
Topic: How to: set the output level of a stock unit?
Replies: 10
Views: 3455

Re: How to: set the output level of a stock unit?

if its a BF2, its as easy as changing values on the fnal mixing opamp. on delay based effects, even if the overall gain is set at unity, the perceived volume may be different, due to the mixing of the delayed signal, arbitrarily out of phase with the input Think: if you run a perfect waveform throug...
by cpm
24 Sep 2009, 13:53
Forum: Pimp-My-Cheap-Pedal
Topic: How to: set the output level of a stock unit?
Replies: 10
Views: 3455

Re: How to: set the output level of a stock unit?

usually a volume drop appears on non-gainy pedals, that is, modulations and the kind. i usually look first at the output stage. Sometimes its difficult to apply a simple patch to increase output, so you have to go back to the input stages. Since its usually a small bit of volume there shouldn be any...