Ashdown Engineering CTM-200R 200 Watt All Valve Rackmount Bass Amplifier User Manual
- June 3, 2024
- Ashdown Engineering
Table of Contents
Ashdown Engineering CTM-200R 200 Watt All Valve Rackmount Bass Amplifier
User Manual
Thank you for purchasing your Ashdown Engineering Amplifier and welcome to the
family! We really think you’ve made the right choice and know that this
amplifier will give you years of great tone and service.
It is a machine though and needs to be looked after, please read through this
user manual which will help you get the most out of your new Amp and keep it
running as long as some of our happiest and very famous customers.
REGISTER ONLINE
Please register this product online so we can make sure we give you years of customer support through our friendly in-house service centre.
Here is where you need to visit to register your product:
http://www.ashdownmusic.com/pages/register-your-product
If you don’t have access to the internet or do not wish to register online you
can do so by post. Please complete the warranty registration card and return
it to the address below :
Ashdown Design and Marketing Ltd, The Old Maltings, Hall Rd Heybridge, Maldon,
Essex , CM9 4NJ, UK
INTRODUCTION
The CTM 200R is one of the CTM series of handmade amplifiers from our specialist workshop here in the UK, built to order and built to last!
Quality components are used throughout and when used as designed the amplifier will provide you with years of service.
There are a few points to ensure that the amplifier performs as expected,
these are listed below :
The amplifier is designed to be Rack mounted using the Front and Rear
mountings, it is not sufficient to try to use the front mountings only!
The amplifier is fan cooled , it therefore follows that there MUST be a free flow of air around the unit, air enters at the front top cover and is exhausted at the rear.
Always ensure the speaker is connected BEFORE you turn the amplifier ON!
FRONT PANEL FACILITIES
INPUTS – There are two inputs provided of differing sensitivities.
HIGH suits high output instruments input impedance 100k.
LOW suits low output instruments input impedance 100k.
EFFECTS SEND AND RETURN – These 1/4” jack sockets should be used to connect to an external effects device or pedal board. The EFFECTS SEND output should connect to the INPUT of the effects unit, and the output of the effects unit should be connected to the EFFECTS RETURN input.
EQ CONTROLS – Fully passive equalisation featuring bass, middle, treble
controls together with an associated push button that changes the
characteristics of each control.
The bright switch adds extra brilliance when using lower stings of the Master
volume control.
GAIN – This controls the level of the signal sent to the MASTER section. To achieve a cleaner sound, turn the GAIN control down and the MASTER up. To achieve a richer, more distorted sound, turn the GAIN control up and the MASTER down.
MASTER – This controls the overall output of the amplifier.
MUTE – In the on position, this switch mutes the out put of the amplifier (useful for tuning, etc.).
PRE/POST – This switch determines whether the signal from the DI OUTPUT (see Rear Panel Facilities) is taken before/PRE the EQ section (down position) or after/ POST (up position).
VU METER – The VU meter fitted to the CTM200 has associated with it a 6
position switch, the first 4 positions are used to set the bias on the
amplifier thus removing the need for access to the amplifier internals, the
second 2 positions are used to indicate the power being supplied to the
speaker by each pair of tubes.
In normal use the meter should be set to either pair of tubes and it is
therefore possible to check that both halves of the amplifier are supplying
equal amounts to the connected speakers. Note that the meter will never
indicated zero when the amplifier is switched on.
REAR PANEL FACILITIES
DI OUTPUT – The DI outputs is transformer driven, a PRE/POST switch is provided to enable selection of PRE EQ or POST EQ signal source. Note that if there is a need to “ground lift “ the DI this should be done at the connected piece of equipment .
SPEAKER OUTPUTS -2/4/8 Ohm outputs are provided on the rear panel, Use ONE output socket at a time, closest to the impedance of the cabinet combination you are connecting.
SPEAKON CONNECTORS MUST BE USED, if jack cables are used and the connection fails there is a very real possibility of damage to the output transformer or output valves! Damage so caused will not be covered by warranty.
THE VU METER
The CTM 200 meter switch has 6 positions , the first 4 are used to set the bias on each individual output tube.
To Check the Bias, connect the speaker and switch on, allow the amplifier to warm up for about 15 mins , Turn Gain and Volume down to zero and depress the MUTE switch. There now should be almost no noise coming out of the speaker.
Using the switch select each Valve in turn and using a trim tool carefully adjust the 25 turn adjuster to set the needle for that valve as per the diagram above.
Once all 4 valves have been adjusted return the selector to one of the last 2 positions.
If one or more of the valves has NO indication on the meter before suspecting the output tube check the 315mA quick blow fuses ( There is 1 for each valve located next to each respective valve). This will require care full removal of the cover to access the fuse holders.
A continually blowing fuse would indicate either an incorrectly biased output valve or a defective output. Note. Also blowing fuses can indicate an incorrect load!
VALVE COMPLIMENT :
4 x JJ Electronic KT88
3 x JJ Electronic ECC82
1 x JJ Electronic ECC99
1 x JJ Electronic ECC83
SPECIFICATIONS
Input sensitivity: 100mV/300mV nominal
Output Power: 200 watts continuous avg into 2 /4 or 8 ohm speakers
Mains supply: Externally switchable 115V/ 230V. or 115V/ 240V @50/60 Hz
Power consumption: 485W average
DIMENSIONS
17.9” (455mm) W x 5”(128mm) H 3U x 13.8”(350mm) FTR
Rack mountings supplied.
