Question for Ashdown CTM100 owners

[BassAdder27]

Question for past and present owners of the Ashdown CTM100 head

I have discovered for some reason this amp really excels and sounds best when you play with a pick

Finger tone is great of course but the EQ and natural sound of this amp just comes alive when pick playing

Anyone else found this the case ??

My ABM600 head is equally matched fingers or pick but the all valve CTM100 just sounds gorgeous with a pick especially as a rock amp

 

[Wasnex]

I own the CTM300 rather than the CTM100. I believe the CTM 100, 200, and 300 all use the preamp.

The CTM300 is the darkest tube amp in my collection. It seems intended to make a modern cab sound similar to an SVT through an 810E. I think an SVT and 810E also sound way better with a pick than finger style (YMMV), so I don't find your observation surprising at all.

While I think this amp sounds great, it does have a pretty strong baked-in tone that you can't really dial out with the tone controls. Also the tone controls can be maddening as they don't necessarily work as expected. The individual controls are intended to be extremely interactive. So, depending on the position of each rotary, making an adjustment may give you the opposite of what you expect or produce no perceivable change at all.

After extended frustration, I eventually developed a strategy that I find very useful. Start with the rotary controls at 9:00. Then limit adjustments to +/- two clock face settings. So the most useable range is about 7:00 to 11:00. Within this range there are a variety of good sounds. You can definitely crank the controls up higher, but I find it's really easy to dial in a sound that I would consider bad if you get to aggro with the settings.

I find the Bass control is fairly weak and does not really produce any noticeable results above about 11:00.

The Mid control seem to dominate. If you crank the Mid control past about 11:00, then the position of the Bass and Treble controls don't matter.

The Treble control is sort of ironic, as it seems to do the opposite of what you expect. The Treble control never seems to boost the highs. If you push it up to about 11:00 it seems to provide a very small, almost imperceivable boost in the low mids. If you push it past about 2:00 it starts pulling out the low bass. I think it might be useful if you want a scooped sound. I.E. Use only Bass and Treble controls with Mids fully CCW.

I think the issue is the low frequency cut off of the Treble control is super low. Turn the Bass and Middle off (fully CCW), and turn up the Treble and the sound will have a surprisingly amount of lows. Turn up the Bass and Mids and at some point they sort of with the Treble control. The crispest highs seem to be with the Bass and Mids turned up a bit, and the Treble fully CCW.

 

[foal30]

Definitely like using a plectrum when running through the CTM-300

 

[foal30]

CTM is definitely an Amp to spend time with regarding the EQ section/controls

In my opinion it’s certainly well worth the time. It’s the best Amplifier I have owned in 30 something years of playing

I don’t think it’s the Amp for everyone but I couldn’t be without mine

 

[Dynacord]

Going to have to try it with a pick. I absolutely love the amp played fingerstyle. Pretty much my favorite amp to date. Like foal30, hard to imagine being without it now.

The push-buttons make a big difference...

 

[keatz]

Hi, Ive got my first tube amp on the way. CTM-100.
Can someone please explain it to me in simple child terms, which order to use the preheat and main HT switches when turning on and off???

I would assume you turn preheat on, wait for tubes to warm up and then turn main on. So while using both switches are on.
Then when you are done, turn main off but leave preheat on for a few minutes, then turn preheat off, wait to cool further and move.

Is this correct?

 

[Wasnex]

Is this correct?

Turn On Sequence:
1. Turn on Preheat and let the tubes warm for a bit. The recommended time varies from about 30 seconds to 5 minutes.
2. Turn on Main HT
3.

Turn Off Sequence:
1. Turn off Main HT
2. Turn off Preheat. I may wait a few seconds with some amps, but not for cooling. It's to keep the tube heaters warm longer. The idea is for the tubes to continue conducting for awhile after the HT supply is turned off. This allow the tubes to draw down the HT voltage. Most amps have power supply bleeders to do this, so you don't need to wait.
3. Wait for the tubes to cool before moving. If time allows, give them about 15 minutes. If you are pressed for time, give them at least 5 minutes.

 

[oli]

Going to have to try it with a pick. I absolutely love the amp played fingerstyle. Pretty much my favorite amp to date.

The push-buttons make a big difference...

+1 I got my CTM 100 today I upgraded from the CTM 30 (Chinese made). But there is one thing that bothers me: the noise (hiss) is way louder than the CTM 30 at the same volume. I bought the Amp mainly for my home studio, recording and practising so this is a problem. Any suggestions if/how this can be improved?

 

[Wasnex]

+1 I got my CTM 100 today I upgraded from the CTM 30 (Chinese made). But there is one thing that bothers me: the noise (hiss) is way louder than the CTM 30 at the same volume. I bought the Amp mainly for my home studio, recording and practising so this is a problem. Any suggestions if/how this can be improved?

Pretty sure CTM100 and CTM30 are voiced very different. I have a pair of LB30s (Mk1 and Mk2). The two amps are a bit different from each other, but neither sounds like the bigger CTMs. The Original CTM 30 was claimed to be an LB30 with different cosmetics.


I also have the CTM300, which is supposed to use the same preamp as the 100. My 300 does not have any sort of problem with hiss or hum.

Is your amp new? If yes, then you may need to consider a return or warranty repair. You can open a ticket through the Ashdown webpage. Sometimes they are out of the office, and it can take awhile to get a response.

If the amp is used, I would suspect someone may have replaced some of the original preamp tubes with higher gain models.

How do the controls impact the hiss?

The schematic I have has some obvious errors, but this is the signal path it shows.

Input network->V1a->Effects Loop->Gain->V1b->Tone Network->V2b->Bright Switch->Master->V3a (pre driver)->V3b (phase inverter)->V4a,b (driver)->Output Tubes

The 100 uses ECC832 (12DW7) tubes. The "b" triode is like a 12AX7. The "a" triode is like a 12AU7, which is much lower gain. If a 12AX7 is subbed for a 12AU7 it may result in excess hiss.

I would suspect V1a, especially if adjusting the gain has a big impact on the level of hiss. You could try plugging your bass into the effects return.

V2a is used to drive the DI, so it's not in the amps signal path. V3 and V4 should be 12AU7.

Make sure you bass is plugged into the hottest input. This will allow you to run the Gain control at a lower level. However, the front end of my 300 can be pushed to distortion if you use the hottest input. So if your bass has a hot output, you may need to use the attenuated input.

With the hot input, the preamp may run out of clean headroom with the Gain around 9:00. In the attenuated input, you may need to crank the gain up to about 2:00...which can result in a little hiss.


Dual Triode Tubes:
12AX7, ECC83, ECC83S, 7025, etc are the same tube type. Gain factor is about 100 (for both triodes).
12AU7, ECC82, 5814 etc are the same tube type. Gain factor is about 20 (for both triodes)
12DW7, ECC832, 7247, etc are the same tube type. (One 12AX7 triode, one 12AU7 triode).

Any of the tubes could be the source of the hiss. You could try replacing each preamp tube with another of the same model.

Also check to make sure the bias is properly set and balanced. Running the output tubes too hot can result in a little bit of hiss. If the current is not balanced between both tubes it will result in hum. The resulting hum is like a dull roar.

 

[oli]

Thank you Wasnex! It seems I was too impatient. After a few hours of warm up the noise has disappeared almost completely. I still get some hiss if I crank the gain or boost the treble.... But at "normal" setting there is almost no hiss

 

[oli]

I don't want to high jack this thread, but has anybody "upgraded" the tubes in the CTM 100 (or CTM 300)? If so: was it worth it?

 

[Wasnex]

I don't want to high jack this thread, but has anybody "upgraded" the tubes in the CTM 100 (or CTM 300)? If so: was it worth it?

Pretty sure the factory tubes are JJ KT88. I am pretty much a fanboy. Although they have some reliability issues, I think they are better than other KT88s in MI market segment.

I have a bunch of amps that run KT88, and most of them are running JJs. For me JJ KT88 has been the most stable and reliable.

I have an Aguilar DB359 that is running Svetlanas. I believe they are pre SED Winged C. For fun I swapped in a set of JJs. I couldn't tell the difference. The company that made Winged C is long gone.

The 2nd largest population of KT88 in my collection is Shuguang. I am able to hear a difference with Shuguang. I preferred the JJs and Shuguang hasn't made tubes for quite awhile. I felt the Shuguangs were probably a close second for reliability. I had quite a few problems with various Shuguangs, but most of them were old and worn when I got the amps. However, a new quad of GEKT88 I bought has been very drifty and I expect they will not last long.

The smallest population of KT88s in my collection is New Sensor, including EHX and Sovtek. I am able to hear a difference with New Sensor made tubes. Some of these have sounded really good in a different way than JJs, but my impression is they tend to be more drifty and less reliable. I have had more problems with New Sensor KT88 and 6550 than JJ and Shuguang combined.