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Ashdown CTM300

jumbodbassman

jumbodbassman

Dec 28, 2009
5,476
1,871
Stuck in traffic -NY & CT
Disclosures
Born Again Tubey
#1
So i bought the ashdown head that was being sold by music farm. and i plug it in and get no sound. instructions really none existent. so i turmn on the green heat up tubes button, and then the switch next to it.. NO sound... cable and speaker checked OK with another head. If i press the bias button is see some action on the little graph thingy. but back to speaker nothing. i feel like an idiot but before i return it i want to make sure i am not doing soimething really silly and m,issing a switch. any help???
 
#3
jumbodbassman said:
So i bought the ashdown head that was being sold by music farm. and i plug it in and get no sound. instructions really none existent. so i turmn on the green heat up tubes button, and then the switch next to it.. NO sound... cable and speaker checked OK with another head. If i press the bias button is see some action on the little graph thingy. but back to speaker nothing. i feel like an idiot but before i return it i want to make sure i am not doing soimething really silly and m,issing a switch. any help???
Click to expand...

Did you try the mute button. It's right above the master volume.

A couple of other pointers.
The preamp is very high gain for a bass amp. Using the Low input, the preamp may begin to distort with the gain at 9 o'clock. If you have trouble getting a clean sound, use the High input. Ashdown's confusing terminology relates to the bass's output...IE high gain input for Low output bass.

Start with all tone controls at 9 o'clock. They are pretty intuitive from off to about 10 o'clock. Above that operation is a bit unpredictable. They are designed to be extremely interactive.

I usually like the mid shift button pushed in. This actually impacts the upper knee of the bass control rather than the mid control. If the bass control is turned down, the button will not have any impact on the sound.

The mid range control pretty much dominates above 10.

On my amp, the brightest sound is with the treble knob dialed all the way off. As you increase the control to about 10, it adds a very slight amount of low mids. When the control hits about 2 o'clock it will start pulling out some of the bass.

Optimum bias for the tubes is with the meter pointing straight up. Lower is okay...it's not recommended to set the current higher. My amp needed a simple resistor change in the bias circuit to get the tubes in the proper range.

The white light for the meter will probably burn out if it hasn't already. There is also two red LEDs that come on when you put the amp in bias mode. People assume the bulb is 6.5V as that is what most amps use. The socket in the CTM300 provides 8V and this is normal. I bought a couple of 12V and 14V bulbs and they work fine. Also there is an 8V bicycle bulb that is sold in England that Ashdown recommended. To get them in the states you need to order more than one. I can provide part numbers and comments if you like.
 
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#6
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There is no light above the Master. The mute switch is just above the master, and the Audio/Bias switch should be on Audio. You'll be able to tell because the VU meter should drop to nothing until you give it a signal. The VU meter also changes color depending on which mode you have on. I believe Bias is green and Audio is red.
Have you tried the High or Low inputs?
Have you tried running a signal into the Return of the FX?
 
#8
BlushResponse said:
Yup, I double checked; if the VU is RED it's in BIAS mode. I got it mixed up.
Click to expand...

This is correct. The white incandescent light in the meter is on all the time unless it is burned out. The image in the picture with the yellow background is how the meter should appear in audio mode. The red led comes on when the bias button is pushed. If the tubes are biased properly, the meter should drop to about 10-20% when the amp is in audio mode. I know it's weird, that's just the way the meter is wired. The meter only goes to the end stop when the amp is in standby or off. The manual advises to not play the amp with in bias mode.

If the mute switch didn't get you some sound:
1. Are all of the output tubes biased to at least 10 o'clock on the meter? Put the amp in bias mode and select each tube 1-6. You should get sound with a lower meter indication, but the power will be low. If there is no current through one or more tubes. Each tube is fused individually to protect the amp.
2. Is there any hiss in your speaker when the amp is in operate mode? You should hear a faint hiss if the tubes are pulling current.
3. Try plugging your bass into the Effects return...The gain and all tone control are located after the return....turn all controls to at least 9 o'clock...if no sound, turn them all the way to the right///to the max.
4. If you have a mixer or preamp with an XLR input, try monitoring the CTM300's DI output and switching between pre and post.
5. If you mail ordered the amp, I would call and ask them whether they want to pay to repair or return the amp. If they are local, take the amp back and ask them to either repair it at their cost or give your money back.

The amp has a very unique voice, is very powerful, and appears to be well built. I think it would be worth some effort to get it running, but the seller should bear the cost.
 
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#9
I would probably be checking to make sure all the small signal tubes are inserted properly in their sockets...but I don't advise doing this without contacting the seller first. If one of the small signal tubes is not pushed in far enough, the signal will not pass through to the output section. Worse, if someone installed one of the tubes improperly, at least one pin would have to bend over, and the other pins would make improper connections that could result in damage to the surrounding circuitry.

This amp uses two ECC832 (12DW7), two ECC82 (12AU7), and one ECC99 small signal tubes. It's possible one of these tubes is bad and simply needs to be replaced. Note: As of 2:26 AM 6/7/2018 I have received confirmation that the Ashdown Website lists the wrong tube complement for the CTM300. Per the amp's designer, the info above is correct, and an effort will be made to update the web pages.

If you decide to check the small signal tubes. Unplug the amp and remove the metal grate on top of the amp. With the front of the amp facing you, remove the KT88 closest to you on the left. After removing the tube retainer on the KT88, grasp the tube by the metal base and pull up while rocking it gently from side to side. Don't use to much strength with the rocking motion or you can break the guide key off.

To remove the shields from the small signal tubes, press down, rotate, then lift up. I believe you need to rotate them CCW. Here's an image to help you understand how the shields are held in place. Take a look at your tube shields with a flashlight to confirm.
images?q=tbn:ANd9GcSQMPq-yaa34wqdn4lF3KJIEzO3EwVIE-z3OvfSiTRC6TRc4LJ-fw.jpg

Reinstalling the small signal tubes can be a bit tricky, especially when you cannot see inside the amp. So rather than removing them, first try pressing down to make sure they are all properly inserted in the tube sockets. If any of them move a noticeable amount. Reinstall the KT88 you pulled and try the amp. Don't bother putting the tube retainer and tube shields back on yet.

If there is still no sound, don't leave the amp on for long as you don't want the KT88 getting too hot to handle. Start removing and inspecting the small signal tubes one at a time. Check to make sure each tube is not too hot; then grasp the tube firmly by the side and pull up while rocking gently from side to side. Try to keep track of the orientation of the tube so you can look at the pins and see how they match up with the tube socket. Consider putting a direction mark on the tube with a Sharpie before you remove the tube. This may help you later when you reinstall the tube.

Inspect the tube for obvious visual anomalies such as bent or broken pins. You can also tap and shake it to see if it rattles.

If you are only going to inspect and reinstall the tubes, I would do all of them before turning the amp back on. If you plan to troubleshoot using new tubes, I recommend removing and replacing only one tube at a time, so it is clear when you have identified the bad tube.
 
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#11
If it was purchased new, I'd take it back and have them turn it on. Even if you end up looking stupid. Bring your cables and cab if you can. And now that I've said it, does your cab work? Does the DI work? Have you tried using the FX input? There could even be a blown fuse in the amp, depending on your power situation.
When I purchased my CTM300, used, it had fallen and cracked the case. That's why a tube got put back in wrong, since it fell hard enough to break the guide keys on the KT88's. What I'm saying with this is, these amps are practically bomb proof.
 
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#14
BlushResponse said:
If it was purchased new, I'd take it back and have them turn it on. Even if you end up looking stupid. Bring your cables and cab if you can. And now that I've said it, does your cab work? Does the DI work? Have you tried using the FX input? There could even be a blown fuse in the amp, depending on your power situation.
When I purchased my CTM300, used, it had fallen and cracked the case. That's why a tube got put back in wrong, since it fell hard enough to break the guide keys on the KT88's. What I'm saying with this is, these amps are practically bomb proof.
Click to expand...


The amp has a main fuse concealed in the AC plug assembly on the back panel. If this fuse is blown it's basically the same as if the amp is not plugged in.

There is a an HT fuse inside the amp. If this fuse is open, the amp will turn on, but none of the output tubes will show current when the amp is switched from standby to operate. This fuse is not user accessible.

Each output tube also has a fuse. If one of the fuses blows, the associated tube will not work. If the tube is selected on the front panel meter, the meter will set all the way to left on it's end stop regardless of the position of the bias button. These fuses are user replaceable. Repeated failures of the same fuse, indicate a faulty tube, or a tube that is improperly adjusted. If one tube blows, current will no longer be balanced in the output transformer so the amp will produce a dull hum.

Here's a CTM300 gut shut I found online.
upload_2018-6-7_13-53-10.jpeg
 
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#15
jumbodbassman said:
got it new from music farm actually. thanks for all the advice. i will have to try it all before i either return or find an authorized repair guy..
Click to expand...

IMHO...make it a priority to check the output tubes for current and then listen for hiss and hum in your speaker. Put the amp in Bias mode and scroll through the tubes with the knob labeled TUBE NO. It' possible that for some reason your speaker cable is not working with this amp. You can damage a tube amp by operating it without a proper loud, so it's important to confirm the speakers are actually being connected. If the tubes have current and there is no hiss or hum in the speakers, try another cable.

It's possible that an internal connection in the amp came loose. Better to have this fixed before that amp is damaged from operation without a load.
 
#19
jumbodbassman said:
no sound at all. and meter does move.
Click to expand...

Do you mean the meter is moving when you play the bass? This means signal is getting to the output tubes. Meter movement indicates the current level is changing in the output tubes on this particular amp. Either your speaker cable is not making a proper connection with the amp or a connection inside the amp came loose during shipping.

Is your speaker and speaker cable wired the normal way to pins 1+, 1-?

If the meter is moving in response to your playing inputs and a different speaker and speaker cable does not correct the issue, I recommend taking the amp to a technician.
 

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