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14 

6)

 

FREQUENTLY ASKED QUESTIONS 

 

How do I hook up this thing? 
 

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See Section 2, beginning on page 3. 

 
When I plug effects into the effects loop, my tone noticeably changes.  Sometimes the effects don’t sound quite right. What’s 
the deal? 
 

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Generally, what you’re hearing is a significant mismatching of impedances, and/or an overloading of the effect 

unit itself. Most rack-mount units have different input impedance than pedals, and thus can 

sometimes 

function fine without a buffer before them. In addition, 

some 

of these rack-mounted effects can pad the 

volume they receive, preventing it from overloading. Pedals do not have proper input impedance or padding 

ability, and therefore do not play nicely.  

 

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For best results, an effects loop interface like the C-lator or Klein-ulator should be used with the OTS 

amplifiers.  These units prevent impedance mismatching, as well as provide the ability to pad down the 

volume sent to the effects units hence preventing any overloading. 

 
Can I substitute different tube types for the 12AX7/ECC83s or 6L6GCs? 

 

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Although you can try 12AT7s, 12AU7s, 5751s without any harm, the design is optimized for 12AX7s, and are 

therefore the only recommended tube in the preamp positions.  Usage of other power tubes (ex – modern 
6V6s like Electro-Harmonix, JJ) may be possible, but please first consult Ceriatone Amplification or your local 

competent amplifier technician. 

 
What settings do you recommend? 
 

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Try setting all controls at 12:00, and adjust MASTER to a suitable volume. 

Содержание 100W Overtone Special

Страница 1: ...1 Ceriatone Overtone Special S M Edition 50W and 100W amplifiers...

Страница 2: ...of currently 8 different versions within the series In addition we have released the Klein ulator and C lator effects loop interfaces specifically for use with our Overtone amplifiers We have been pl...

Страница 3: ...g a 1 4 instrument cable into the NOR input on the lower left of the front panel 2 Plug a suitable power cable from the OTS s rear panel MAINS cable inlet to your wall power receptacle 3 Plug the OTS...

Страница 4: ...BY for 30 seconds to allow tube filaments to warm up 12 Set rear panel OPERATE STANDBY switch to OPERATE 13 ROCK 3 FRONT PANEL CONTROLS On the front panel of the S M Overtone Special you can see thirt...

Страница 5: ...d tube stage Think of this as a gain control primarily for your clean channel but note it will impact the overdrive mode as well BRIGHT is a high frequency boost that can be used to add sparkle to you...

Страница 6: ...mode RATIO OVERDRIVE serves a sort of volume control for the overdrive channel However just like this version of the original amplifier there are not individual master volume controls for the clean a...

Страница 7: ...P slow blow fuse 3 MAINS power two way toggle switch 4 OPERATE STANDBY two way toggle switch 5 SPEAKER OUTPUT speaker jacks 6 IMPEDANCE three way rotary selector 7 EFFECTS LOOP RETURN instrument jack...

Страница 8: ...our speaker cabinet to the amplifier using these jacks If you use one speaker cabinet use the jack labeled MAIN If you want to run two cabinets in parallel connect the second cabinet to the amplifier...

Страница 9: ...ches between boosted and normal configurations In this series of OTS amplifiers the PAB accentuates midrange frequencies and attenuates low frequencies making it great for cutting through during a sol...

Страница 10: ...X7 ECC83 clean and overdrive stages 1 and 2 V2 12AX7 ECC83 overdrive stages 3 and 4 V3 12AX7 ECC83 phase inverter for power amplifier V4 6L6GC V5 6L6GC V6 6L6GC 100W version only V7 6L6GC 100W version...

Страница 11: ...ry from DMM to DMM 2 Plug a black probe into the color coded jack on your DMM and do the same for a red probe 3 Insert the black probe tip into the black probe jack blue arrow This is GROUND in the OT...

Страница 12: ...ation for 6L6GCs 30W and now some math The formula for calculating bias is as follows In most cases amplifiers are biased between 50 and 75 dissipation We bias the OTS to approximately 35mV 40mV readi...

Страница 13: ...ecessary A FEW COMMENTS ON BIASING Due to the nature of vacuum tube amplification there are inherent risks when biasing your amplifier Extremely high voltages are present and vacuum tubes reach high t...

Страница 14: ...padding ability and therefore do not play nicely For best results an effects loop interface like the C lator or Klein ulator should be used with the OTS amplifiers These units prevent impedance misma...

Страница 15: ...hly recommend the use of a non conductive rubber screwdriver and only adjust the trimpot when the amplifier is not powered and disconnected from the wall outlet DO NOT ADJUST THE OD TRIMMER WHILE THE...

Страница 16: ...the OTS have it and what does it do Yes the OTS amplifier has a PI short for phase inverter trimmer This is part of the original design that controls the balance of plate voltage between the two triod...

Страница 17: ...risk On the next page there are three arrows The ORANGE arrow is the PI trimmer The GREEN arrow is the test point for measuring the plate voltage at V3A The BLUE arrow is the test point for measuring...

Страница 18: ...ue arrow indicates V3B test point Green arrow indicates V3A test point Adjusting those trimmers sounds intimidating Am I missing anything if I don t experiment with them Absolutely not We adjust each...

Страница 19: ...t only in proper lighting o Have a clear idea what trimmer you are going to adjust and how you are going to adjust it o Take your time o If you need to measure values with your DMM keep the black prob...

Страница 20: ...lones Finally we occasionally use NOS components from our vast surplus parts collection in locations they work well and complement the voicing or enhance the performance of the amplifier I like to use...

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