All posts by guitar poppa

About guitar poppa

Former product design teacher, now on retirement and still post war blues guitarist, i've been found of electronics since I was 14... The guitar poppa web site is the way to make known and spread my experience in transistor and tube vintage electronics

Actuality

Project  : An echo box that saturates like Little Walter used to do…actuality : project to come
Get the joyful grit of the Chicago Southside harps !

Little Walter’s echo is like the reverb of punk-surf groups: it is as much a matter of timbre and sound texture as of pure delay. So I thought to add a SpanishMoss overdrive to the echo to get back that special sound… I’ll tell you what it’s going to be !…
Contact me for more information…

Bandeau fin gris moyen - L15

 Custom actuality : An old-fashioned amp head, with plenty of optionsguitar poppa's actuality : a project to come
A development of the Vox AC15…

Initially, a musician’s command based on the original AC15, with lots of options:
A 3-band tone, a booster, a line output with HP simulation, an attenuator …
And all built old-fashioned way on a turrets card (except for the effect loop).
My amps 10 to 25W

Bandeau fin gris moyen - L15

Project : a Di-Box that make your sound before injecting it into the PA.SimSymBox : boîte de direct qui met en valeur la couleur et le grain de l'instrument
To be sure of the sound quality you will send to the sound system of the bar …

Imagine an instrument preamp with adjustable tone and overdrive …
Add a speaker simulator, and a balanced output to the mixer …
You have everything you need to get your sound and send it directly to the sound system!
Contact me for more info and custom realization…

Bandeau fin gris moyen - L15

New : preamps for harp with solo Boost and balanced output to PA.preamps for harp with solo Boost and balanced output to PA
What it takes to be independent on small stages

Initially, an order from harmonica player Vincent Bucher … He wanted a CurvyMama preamp followed by a speaker simulator and a balanced output to the PA …
And also with a chorus push button, and an output for stage amp (if necessary) …
The “CurvyMama SimSym” product page

Bandeau fin gris moyen - L15

New : a 3W microCombo with 13cm speaker
3W microCombo with 13cm speaker
The MicroCombo range now has a big brother

A greedy sound for the guitar or the harp in a beautiful solid walnut box.
The watts are real, as well in clean sound as in light crunch or in total saturation.
Speaker on your choice: Celestion, Sica or Jensen, depending on the desired sound color.
MicroCombo 3W product page

Bandeau fin gris moyen - L15

News from the workshop: pedal modifications
pedal modifications by Guitar Poppa
Gain and roundness improved in a Fuzz Face Lift from Big Knob.

It is a Californian artisanal stompbox, which updates the Tone Bender II Professional with a silicon buffer and a fuzz circuit equipped with Russian germanium MP39A.
I bring more body, a better polarized buffer, progressive gain pot, adjustable bias …
Modifications and customizations by GuitarPoppa

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Custom : a 25W Silicium / Germanium hybrid amp head
25W Silicium / Germanium hybrid amp head
SweetGerm +25W

Association of the SweetGerm preamp and a 25W hybrid PowerAmp.
Germanium brings its color and the grain of overdrive, silicon improves reliability.
Customizable connections: lines, loop, phones etc …
Facebook review from the first client behind the project

Bandeau fin gris moyen - L15

Now available:
CurvyMama, a fleshy overdrive that moves like a round lady !

A preamp-overdrive designed for juicy guitars and harmonicas.
Single pedal or large format, with speaker simulator and XLR3 symetrical output. Interactive and nuanced Contour and Bite settings… And a special germanium grit !
CurvyMama’s product page

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Custom : Pedal duos in a single box
Duos pédales - The Scream + VintageBoo
The [S]cream + VintageBoo

Initially, custom orders from friends … We have selected complementary pedal duos … With an additional economy of scale: a duo is less expensive than the two pedals that it brings together, because some circuits do not need to be repeated.
Contact us to discuss your desires and projects…

Bandeau fin gris moyen - L15

First Germanium Micro-combos from 1W to 3W RMS
Germanium Micro-combos, from 1W to 3W RMS
On the workbench…

These will be two Micro-Combos for harmonica or guitar, respectively 1W and 3W…
The electronics are traditional, without integrated circuits. All germanium power amplifier and selected NOS speaker : The clear or overdriven sound will be lively, warm and rich!
MicroCombo1W product page MicroCombo3W product page

Bandeau fin gris moyen - L15

A speaker attenuator with line output and bypassspeaker attenuator with line output and bypass
CoolCrunch fits in a box to be placed in the bottom of combos …

Realization on request of a harp friend for his Champ 57 reissue …
Two models, dedicated to 5W or 30W power amplifiers.
Continuous volume adjustment, byPass switch and line output always available…
CoolCrunch5 and CoolCrunch30 product page.

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Guitar Poppa likes to repair or update vintage ampsGuitar Poppa likes to repair or update vintage amps
Review and restoration of a french amp from 56/65 …

Renowned French brand: Stimer amplified the great Django, then the first french rockers …
I can repair or transform these old amps with all due respect.
But only small models, less than 25W: my workshop is very small!
(and international transport is so expensive!)

Bandeau fin gris moyen - L15

Pedal mods
GuitarPoppa, modifications, customisations, performances, ergonomie, usages spéciaux
Technical and ergonomic improvements; adaptation to personal uses.

Recently I adapted a [good] copy of TS9® for bass …
At the moment, I am modifying a Metal Zone® for the harmonica …
If your pedal is correctly designed and manufactured, we can customize it to your wishes!
Modifications and customizations by Guitar Poppa

CurvyMama + SimSym

CurvyMama is initially a preamp designed to process the flesh and grit of harmonicas sound. In this aim, It features a special tone circuit and a germanium overdrive stage.

This version + SimSym also features a boost stage.
Above all, it has an active speaker simulator, and a balanced output to the PA console.

CurvyMama SimSym Output, logo


CurvyMama SimSym Output, préampli spécial harmo avec simulateur de HP et sortie symétrique pour liaison directe avec la sono

The first CurvyMama SimSym, a custom order – March 2020.

Continue reading CurvyMama + SimSym

My Amps : 10 to 25 Watts

I make amplifiers for guitar or harmonica … Small, like my workbench !
Available as separate head … One can also order a combo, with a 10 or 12′ speaker.
The layout and the equipment are to be composed “custom” according to your project.

Transistor realizations feature a real power of 10 to 25W on 8 ohms.
They use a 60s germanium technology, which denies the bad reputation of transistors…
It brings especially a natural compression and a progressive transition to overdrive which have little to envy tubes, with a price also compressed!

I also realize high quality tube models, custom 5, 10 or 15W, with vintage or high-end components where it’s audible.

In both cases my aim is to offer amplifiers intended for home use or small concert venues, without technical weakness, and with a sound that will please the instruments.


Continue reading My Amps : 10 to 25 Watts

My stompboxes : DD size

I have designed some large format stompboxes (approximately 20 x 11 x 3.5cm), either because they have to contain a printed board of significant dimensions, or because they have to bring together several cards.

These configurations are often the result of custom orders by musicians with strong choices … Their requests have led me to design typical equipment, which are often associations of existing circuits.
Everyone can now benefit from these experiences, or imagine their own project!


Continue reading My stompboxes : DD size

Samples : LikeYourFace Fuzz

LikeYourFace - logo produit L15x300dpi

Classic smooth option

Big basic Fuzz and heavy riffs, in the manner of the sixties..
Strato-like guitar.
LikeYourFace with Fat preset ; Fuzz @ 15:00 (more is possible ; Tone @ 12:00 (neutral).
Wild thing (neck pickup) : then Shape of things (bridge pickup).


Fuzz used as a light overdrive : Bright Strato blues
Strato-like guitar.
Neck pickup and Bridge pickup mixed.
Fat Preset ; Fuzz @ 10:00 to get a smooth texture ; Tone @ 13h to get more harmonics.

Classic bright option

A scratching sound, with open strings and a bit boosted medium
Archtop Guild X160,bridge pickup at first, the  mixed pickups at the end.
LikeYourFace basic, Classic bright option. Fuzz @ 15:00. No preset nor tone.
In-A-Dadda etc. (micro manche)

Bandeau medium rouge - L15


Recording conditions

Bandeau - Enregistrement - Samples-BirdMaster


2xEL84 amplifier from 1967, restored by me. Clean canal, tone control almost flat.
10″ speaker, Weber F10-150T (recommended for Fender Princeton) ; bass reflex cab.
Shure SM57, placed like in the pic above.
A bit of Holly Grail® reverberation, just for pleasure.

Strato-like guitar from the 80s, rather cheap but equiped with Rio Grande texan pickups.
Archtop Guild X160 from 1988.

Bandeau fin gris moyen - Samples

MicroCombo3W

MicroCombo 3W is a portable and powerful micro-amp for guitar or harmonica.
The all Germanium power amp, the big brand speaker  give to it efficiency and musicality.
It will let you play at home or in small places, connected to an external cabinet or to the sound system of the bar.
Options are available when ordering.


MicroCombo 3W, ampli 3W pour guitare et harmonica - amplification au germanium

MicroCombo3W in its walnut enclosure.

Continue reading MicroCombo3W

My amps : MicroCombos



A MicroCombo prototype on the workbench …

MicroCombos are small 1W and 3W amplifiers. (I mean real watts on 8 ohms…)
They are made in old fashioned way, which gives them a special quality both from a technological point of view and according to their design :

Discrete components, 100% germanium transistors, AB class amplification.
Branded speakers, contemporary or NOS.
Solid wood enclosure (cherrywood or european walnut).

Their clear sound is mild, and they crunch at low level without sounding harsh, with a roundness that has nothing to regret from tubes.
They are well suited for home rehearsals, and even for small parties !
They were originally designed for the guitar, but I quickly grasped the interest of working just as much for the harmonica, taking advantage of the grit of old transistors …

Continue reading My amps : MicroCombos

Germanium transistors for Fuzz – 4

Switching transistors
ex : 2N404 (the american classic)

The first transistorized circuits for automation and computing required specific components that were straightforward in their response but without extreme bandwidth. Rather close to radio frequency transistors, they are distinguished by their reliability and deliberately moderate maximum frequency. Some models may produce a vintage sound grain, suitable for Fuzz Face. They could make as much reference as the ubiquitous small power audio transistors : American do-it-yourselfers have not been mistaken, and have since a long time embraced the classic 2N404 …

Continue reading Germanium transistors for Fuzz – 4

CoolCrunch

CoolCrunch is made to attenuate the volume on the speakers without lowering the master volume of the amp …
One keep then the crunch without breaking the ears …
Due to its small size and simplicity, it fits inside the combos and in your budget.

CoolCrunch 5 & 30. Logo

CoolCrunch5. Speaker attenuator in a Fender Champ 57 reissue

A CoolCrunch5 prototype installed on the back of a Champ 57 reissue.

Continue reading CoolCrunch

LowVoltTube

LowVoltTube is an original pedal that combines two fundamentals of the guitar sound :
— A preamp-overdrive, TS9 type, with its tone control …
— A tube stage included to generate a vintage grain.

The tube is a 50s NOS model, specially designed to work directly with 9V or 12V.
Boutique quality, but for a moderate price !

LowVoltTube preamp/overdrive - Logo

LowVoltTube. Préamp/overdrive with JRC4558 and NOS tube 6ET6 (EF98)

LowVoltTube — First issue, 2018.

Continue reading LowVoltTube

Germanium transistors for fuzz -3

High Frequency Transistors
ex : OC44 (Rangemaster, 1966)

High frequency germanium transistors have appeared as a second generation. Their elaborate technology made it possible to obtain a consequent gain even at radio frequencies : 30MHz, then 100MHz or more.
More expensive, and fragile at the beginnings, they have not been much used by pedal manufacturers, before all concerned by economy and robustness.

The OC44 was however exploited by Arbiter in the first Treble Booster, the Rangemaster, where its gain and bandwidth yet modest worked perfectly.
With the contemporary recoil, we rediscover the quality of these transistors, the fineness of their sonic grain, and their real interest in designing modern boosters and fuzz …

Continue reading Germanium transistors for fuzz -3

Germanium transistors for Fuzz -2

Audio preamplification transistors
ex : NKT275 (Fuzz Face, 1966-67)

These are the most common germanium transistors. They were designed for audio pre-amplification circuits in consumer and mid-range equipment, where they quickly replaced the tubes. They are distinguished by a gain which can reach 200, and a maximum frequency of about 1MHz.

Pedals made in 1966-68 first operated with black glass models like OC75 and then encapsulated glass like OC76 and OC81 … As the AC125 and AC126 by Philips / Mullard were a bit expensive, cheap versions like the NKT275, and some SFTxxx had their hour of glory before being forgotten, then rediscovered around 1990 …

Continue reading Germanium transistors for Fuzz -2

Germanium transistors for fuzz -1

Output audio transistors
ex : AC128 (Fuzz Face, 1966-69)

These transistors were at first designed to drive the loudspeakers of radios and consumer audio products. They are distinct from other families by their dissipable power and their maximum collector current.
In 1967, some models have been known as bringing a so called “creamy” sound texture to Fuzzboxes. Therefore, they gained a reputation that made this family of components enter the guitar effects culture.

Continue reading Germanium transistors for fuzz -1

Stompboxes : BB and B size

Guitarpoppa : pédales


My activity is to design and handcraft stompboxes, preamps or small amps.
It feeds on my experience as a musician and technician trained in the 60s.

Some of my pedals perpetuate the tradition, with updated means.
Others have an original design.

They are usually manufactured in autonomous boxes, most often in the 1590BB american format, approximately 12 x 9 x 3cm, or its narrow version 1590B, 12 x 6 x 3cm …
I also combine two circuits as a duo in a single larger box.

Continue reading Stompboxes : BB and B size

Samples : The (S)cream overdrive

Samples.The (S)cream - Bandeau de titre L15


The 3 presets : classic (=TS9®) ; clear ; deep

3 bluesy improvisations , using each of the 3 presets…
Low drive @ 9:00 — Consecutive presets : classiccleardeep.
Strat-like guitar, neck pickup.

Samples. The Scream. Bandeau fin gris moyen - L15

Texture according to the drive setting

Two different drive settings, harmonies in D …
Classic preset — Consecuting settings : low drive @ 9:00 / mid drive @12:00 / low drive @ 9:00
Strat-like guitar, bridge pickup.


Two different drive settings, on Next time you see me…
Deep preset — Consecuting settings : low drive @ 9:00 / mid drive @12:00
Strat-like guitar, neck pickup.


Two different drive settings, playing rhythm patterns in F sharp minor …
Deep preset — Consecuting settings : low drive @ 9:00 / mid drive up to 12:00
Strat-like guitar, bridge pickup.

Samples. The Scream. Bandeau fin gris moyen - L15

Texture according to the diode mixing

4 different mixings, silicon diodes + LEDs, playing a slow theme …
Successively :  1 : Leds 100%  /  2 : Leds 50% + silicon   /  3 : Leds 25% + silicon  /  4 : Silicon 100%.
Deep preset — Drive up to 1h:00.
SG-type guitar, mixed pickups.

Samples. The Scream. Bandeau fin gris moyen - L15
Recording the samples

Samples : The Scream. Bandeau - Enregistrement avec Stato


• The (S)cream is JTC4558 equipped.
• Diodes :  100% silicon on the first four samples ; leds + silicon on the last.

• 2xEL84 amp from1967, fixed by me. Clean canal, light mid notch @ 500Hz
10″ Weber F10-150T speaker, bass reflex boxed.
Recorded with a SM57 close to the speaker, between dome and edge.
A bit of Holly Grail® reverb…


 

The (S)cream

The (S)cream is an advanced diode overdrive that develops the sonic potential of the classic small green box :
Its sound comes from the TS9, but not exclusively centered on midrange: The (S)cream can as well recover the sound of 1975-85, recall the nervous grain of the first Black Face amps, or generate a contemporary overdrive …

The (S)cream

Overdrive The [S]cream by guitarpoppa.com

The (S)cream —  Basic version and  *** version.

Continue reading The (S)cream