RPA California Special Booster

BSM RPA California

In 1974, right before the start of the "Burn" tour, Ritchie Blackmore changed his live setup. First and foremost, he wanted to play live with an echo effect and made the AIWA TP-1011 reel-to-reel tape recorder his first choice. This unit offered the typical 1/3 seconds echo repeat, perfectly matching Blackmores natural beat. Additionally, Ritchie Blackmore used the integrated microphone pre-amp as a booster, and with this his beloved Hornby-Skewes treblebooster he used for many years was not longer needed and was sent into retirement. The necessary trebleboost function (from a technical point of view a "highpass" function), was built into his heavily modified Marshall Major 200 amp. This first remarkable modification of the Major's pre-amp stage was done in the Marshall factory, resulting in a raw and fat tone, you can hear on the "California Jam" recordings from April, 1974. Later on, a new mod was done, resulting in biting, piercing highs with a tight bass, the "Live in London" tone as well as for the rest of the Deep Purple Mk3 period. This two, totally different tones are integrated into the BSM "RPA California", and with the help of the "BITE" control pot, you can smoothly blend them, so the BSM "RPA California" is all you need to cover the complete sound-spectrum of Blackmore's Deep Purple Mk3 time. The Major amp now received a cascaded pre-amp stage with a new, non-bridged cathode resistor at one of the triode stages to prevent to much overall gain. Further on, the 250Ohm screen-grid resistors of the four KT88 power tubes were changed to 1kOhm and the two 10uF electrolytic filter capacitors of the BIAS power supply were replaced by two 47uF (160volt minimum) caps. After 1975, Blackmores tech did several fine tunings over the years to Ritchies Major amp, because Ritchie experimented with several pickups in his guitars as well as with several new ideas of his trademark sound.

Not everybody owns such a heavily hot-rodded amp, and if so, for sure it will not have the correct highpass cutoff frequency! So BSM had the idea, to not only rebuild the AIWA preamp stage, but to also integrate the important highpass function with the original cutoff frequency. The BSM RPA California emulates both typical soundshaping functions in only one stompbox - another BSM first ! The EQ control allows a tonal fine tuning for the use of the RPA California with different pickups, amps and speakers for an optimum in versatility. Depending on the pickups, the sweet spot of the EQ control is located between 12:00 and 03:00 o'clock. As a soulmate for the RPA California, you can use any mild sounding amp with a good master control function. Plug it in front of the CLEAN or CRUNCH channel, but don't use the high-gain or distortion channel! Because of the EQ control, you can use all kinds of pickups, from the historical correct brilliant sounding low-gain Fender Custom Shop 69' (aka "Abigail Ybarra" pickups) up to the thundering Seymour Duncan "Quarterpounds".

The RPA California Booster is inserted between guitar and amplifier, not into the FX loop. The magical tone is achieved by the interaction between guitar pickup, booster and amplifier. The unit is powered by a 9V battery with a current consumption of approx. 350 uA. The average output level is 9dBm, the maximum output voltage when the strings are struck really hard is 7V max. Because of the external DC jack, you can power the RPA Major with 9volts.

Note: The negative pole of the battery is ground!

Booster Image: RPA California Special Booster

BSM RPA California Treble Booster Review (Sound like Ritchie Blackmore)

With lace sensor pickups:

With Custom Shop 69 pickups and ash strat:

With japanease texas special pickups and ash strat:

LUZI EMANUELE from Rome, Italy with the following equipment: Fender Stratocaster vintage 70, BSM "RPA California special booster", Marshall bluesbreaker 30 watt
If you have any questions concerning our products, especially the BSM RPA California Special Booster, our tech-head and mastermind Mr. Bernd C. Meiser would be happy to talk to you. So don't hestitate any longer and send him an email to info@treblebooster.net or use the contact form to contact him.


Hi Bernd, This is Steve from Steve’s Music center Just got this email.....I would love to get one like this every day. Hey Steve, I just wanted to let you know I received the pedal and I'm very happy with it. It's not very often in life you buy something unseen and it live up to your expectations; the BSM "RPA Special Booster" did -- and then some! It was expensive but I feel I truly got what I paid for: Ritchie Blackmore in a box! The pedal does exactly what I needed it to do: it drives my tone achieving a smooth, violin-like tone that is picture perfect for a Strat and obviously very Blackmore-esque. Most overdrive pedals add unwanted overtones but the BSM is very transparent. It's nice! Anyway, it might seem silly but in a way you kinda made a dream come true: I'm on a budget, but you cut me a deal and I've found my golden tone. Thanks a lot! By the way, if you have a newsletter sign me up. You're now my new "Musician's Friend"! Best, --Michael Just thought you'd like to see that. Sincerely,
Steve’s Music Center
Hi Bernd, Ende letzten Jahres habe ich bei Dir den RPA California gekauft und ich wollte nochmal Danke sagen für das Gerät! Ich habe damit jetzt ein paar Gigs gespielt und bin nach wie vor super zufrieden mit dem Sound. Alles schmatzt und singt , das is schon geil. Das nachgeschaltete Delay verträgt sich auch prima mit dem California. Allerdings gebe ich das Signal leicht abgebuffert an das Gerät aus. Viele Grüße, Reik
Reik Rising
Hallo Bernd, ich habe die Treblebooster gestern am Marshall gespielt und meine Wahl ist auf den RPA California gefallen. Ich hätte nie gedacht, was dieses Teil aus dem Marshall macht, bzw. herausholt. Es kommt ein unglaublicher Druck aus den Lautsprechern und der gesammte Sound klingt viel frischer und durchsetzungsfähiger als vorher. Eigendlich dachte ich man müßte ein 200 Watt Marshall Fullstack spielen um an Blackmores (DP Mk3) "Live in London" Sounds zu kommen. Seit gestern weiß ich, 50 Watt reichen vollkommen aus. Ich hatte leider vor ein paar Monaten die 60's Fender Singlecoils meiner Strat gegen andere Pickups ausgetauscht und war skeptisch demgegenüber. Aber auch daß lässt sich prima mit dem EQ vom California korrigieren. Unterm Strich ist es so, daß ich eigentlich sehr erschrocken darüber bin, wie nah man eigentlich an den Blackmore Sound kommt. Absolut der Hammer!
Reik Rising
Hi Bernd, I have good news.... I tested some of your pedals.... HS-C - Fireball - 71/73 - and RPA California. They are fantastic.... great sound. Sound is very similar to Ritchie's sound. Now I have these 4 boosters. If you want to play Deep Purple & Rainbow songs these boosters are ABSOLUTELY NECESSARY!!!!
Emiliano Lupi
Hi again Bernd, as expected, the California pedal sounds great! My new favorite pedal. The bite knob is amazing and so useful! Thank you so much! Take good care Bernd!
Erol Sora