Guitar changed with new one. Problem still here.
Guitar and amp changed. Same problem. I wrote to markbass about that. This my email.
Hello.
I live in Turkey and i bought Markbass CMD151P Jeff Berlin amp 1 year ago on 16.02.2018.
I am a saxophone player for more than 10 years and i am new at bass guitar.
I am a fan of Jeff Berlin and i bought Jeffs Cort Rithimic 4 passive bass guitar, Markbass Cmd151p JB amp and Neutrik silent plug guitar cable.
When i first start to practise guitar with this setup, i didnt know many things about sound of bass guitar and amp. But after getting used to that i noticed something makes me crazy.
I turn the amp on and i practise for about 5-10 minutes. Its sound good, bright, full, nice. After than the sound will be weak, volume is little bit down, feeling is hard to play and not responsive. Then i stopped to play and wait for about 5 minutes (wait with turn the amp off or wait without turn the amp off), the sound is full and rich again but only for 2-3 minutes. Then again same issue.
I checked everything. I got measured the ground and electric with Fluke ground tester. It is normal.
I changed the electric socket and i also try using ups socket.
I tested it at my work and home still had the same problem.
3 months later I take my all setup to the shop that i bought the amp from. They didnt notice the problem but they accepted to replace the amp with new one (Thank you Zuhal Music). I waited for new amp for coming 2 months.
After a week I saw the same problem again with the new amp. Then i thought it is about the guitar.
I sent my guitar to its official service in Turkey. They sent back to me and they said guitar was ok and no problem. But i had still have a problem. I sent my guitar to them again. They said same.
I am an electronic technisian an i think i can do:
I changed the pots, cap, cables in my guitar. The problem was still exist, sound still weak and little bit volume down feeling.
I thought it was about pickups on my guitar but i dont have any other pickups to try.
After fighting for about 2 months with the guitar service, They accepted to replace the guitar with completely new one. But they still thought old guitar was ok.
At last i have new guitar and currently i have same problem.
With second amp and second guitar, i have same problem.
I thought guitar has a really simple structure and i think i need to control the amp head for temperature. As i said i am an electronic tech guy and if any electronic compenent in circuit is too hot, some interesting problem can be appeared.
I remove the Combo Head II from its cabinet and looking into it with the thermal camera (Testo 885) while amp is running but with no connection to the speaker and with no connection to the guitar. Only l plug power socket and switch it on. Also gain and main volume control turned off. After very short time (3-4 minutes) i see really high temperature on some resistors, diod and regulator of the amp is running under zero load. I took the several thermal photos with the tempeture indicators. Temperature are between 70C° to 100 C° of these components.
If needed i can send these pictures with jpg format or i can send them with bmt format for analysing with details.
I talked this situation with the shop i bought amp is Zuhal Music.
They said: they changed the amp before and it is hard to think the second amp has this same problem. They said: i need to send the amp to their service in Istanbul is Des Electronic for control.
On 22 April 2019 i sent the head unit of the amp to this service.
On 29 April 2019 Technician called me on the phone. I explained the problem and send him the thermal photos of the amp. He said: he need to control the amp than he will phone again.
On 2 May 2019 He called me and said he controlled and didn't see any problem on amp and he will send the amp head back to me. He thinks these temperatures are normal because amp heads' roof is open and fan can not be effective but i don't think so.
Yes, some components with aluminium heatsink can be hot because of their characteristics but HIGH temperatures are not normal for smd diods, resistors etc.
In two days the amp will be here. I am waiting.
I am too unhappy. I wanted to learn bass as a second instrument and i thought i selected good guitar and amp. But i could not practise and could not love this instrument because of this technical problem.
My friends and my musician friends can see the problem but sellers and services dont agree with me.
Bass love in my heart will stay only be for listening, if i can not sort this problem out. Most probably i will sell all the equipments and give up learning bass if i can not solve this problem.
Please aproach positively and fix this problem together.
I want to believe Markbass is a music lover company and Markbass does not want to make musicians unhappy.
I can try everything what you say with your directives. I am a tech guy and i can understand what you explain. Lets fix this problem.
I attached some thermal photos.
Best regards.
