Volume pedal

Posted by: Bert Aarts

Volume pedal - 02/06/13 10:11 AM

I found a volume pedal for sale on the internet. The type is PVP12 , brand Proel. I did some research and found that it has a 100kOhm potentiometer in it. Can this be used as expression pedal fot KN7000?
If not, what should be the value of the potentiometer?
May be I can modify?
Bert
Posted by: Bert Aarts

Re: Volume pedal - 02/06/13 11:49 AM

I did some further research on the internet and found that the PVP12 originally is ment for guitar. It has input and output and must therefor be connected between source and amplifier.
I wonder if this can be used with KN7000 because there is only one connection for the expression pedal. I think that every expression pedal only consist of a potentiometer which can be changed to meet the requiredvalue. Maybe I am wrong.
Is there any expert on the forum that can tell me about the electrical diagram of the original Technics expression model?
Hope to get the answer soon because I have a reservation at seller up till tomorrow.
Bert
Posted by: Bert Aarts

Re: Volume pedal - 02/06/13 12:59 PM

PVP has two mono output jacks so besides the valuu of the potentiometer also this must be modified into one stereo jack?
Bert
Posted by: Bill Norrie

Re: Volume pedal - 02/06/13 04:26 PM

Hi Bert,
The Technics Volume Pedal uses a nominal 20K Ohm potentiometer.

The extremities of the pot. are connected between the Tip and Sleeve of a 1/4 inch Stereo jack plug, and the Slider of the pot. is connected to the Ring (Middle) connector of the jack plug.

The Tip and Sleeve connections should be arranged in such a way that when the pedal is fully depressed, the resistance between the Ring and Sleeve of the jack plug is minimum. See the attached diagram......
Posted by: Bert Aarts

Re: Volume pedal - 02/07/13 01:58 AM

Thanks a lot Bill, this is exactly the information I need. I can buy the PVP12 for only 10,- so it is worth trying to modify. Maybe it even is not necessary to modify the pot, only the connection. I will let you know the results.
Bert
Posted by: Bill Norrie

Re: Volume pedal - 02/07/13 02:36 AM

OK Bert,
If you don't change the 100 KOhm Potentiometer, you may find that the Volume change only takes place toward the end of the pedal travel, rather than a smooth transition over the entire travel of the pedal.......
Posted by: Bert Aarts

Re: Volume pedal - 02/07/13 03:04 AM

I understand Bill.
The original potentiometer is 200kOhm and depending on input impedance of KN7 this may cause non-linearity.I will check after receival of the pedal.
Bert
Posted by: Bert Aarts

Re: Volume pedal - 02/09/13 06:59 AM

I bought the PVP12 pedal and made a cable with stereo jack plug for KN side and two mono jack plugs for pedal side. This works fine exept that volume decreases when pedal is depressed. After modifying the potmeter connections in the pedal this was solved. It is not necessary to modify the potentiometer (100kOhm, not 200kOhm as mentioned before) because the volume transition is smoothly.
Thanks for you advise Bill.
Bert
Posted by: Bert Aarts

Re: Volume pedal - 02/09/13 08:20 AM

As mentioned in my previous post the volume pedal works fine but there is a small problem that I noticed. When I load a sequencer song it sometimes happens that the volume is at the level of the KN main volume . I have to press and depress the pedal one time to get it working. It depends on the sequencer song, so not all sequencer songs have this problem. I wonder whether this is caused by the pedal (100kOhm instead of 20kOhm) or by the way the song was recorded?
Any idea?
Bert
Posted by: Bill Norrie

Re: Volume pedal - 02/10/13 03:33 AM

Hi Bert, are you sure the Volume pedal is set to adjust 'Total Volume' ? Press Program Menus > Control > Foot Controllers > Check Expression Pedal is set to 'Total Expression' - Not 'Part Expression'........
Also, check that that the 'APC/Sequencer Volume' slider (Top Left of the KN7000 control panel) is fully upwards.
Posted by: Bert Aarts

Re: Volume pedal - 02/10/13 04:20 AM

Bill, yes both settings are as you mentioned. If it happens the pedal does not react at all and the volume is very loud. I have moved the pedal one time it is o.k. and remains o.k. untill I load a other sequence song, but not with every sequence song.
Bert
Posted by: Bill Norrie

Re: Volume pedal - 02/10/13 04:33 AM

OK Bert - when you have time, email me one of the songs which shows the effect and I'll have a look at it. Or, is it one of my sequences ?????
Posted by: Bert Aarts

Re: Volume pedal - 02/10/13 08:06 AM

Hi Bill,
Please check your mail
Bert
Posted by: Bert Aarts

Re: Volume pedal - 02/12/13 08:12 AM

The problem is not related to sequncer songs because the problem also occurs immediatly after swiching on the keyboard. I always have to press the pedal one time after switching on the keyboard or loading a song. If I do not, the volume will be as set by main volume, independant of position of pedal.
It even is not related to a possible wrong value of the potentiometer: I simulated the original resistance value of the Technics expression pedal (20kOhm) by connecting a 22kOhm resistor between tip and sleeve of the jack and by shortcutting tip and ring of the jack, thus simulating a non- pressed pedal. The volume should be zero after switching on but it isn't, the volume is as set by main volume.
I like to know if this also happens with the original expression pedal and if not what could be the cause?
BTW: I assume that if pedal is connected the function of main volume control is to limit the range of pedal. Is this correct?
Bert
Posted by: HarryG

Re: Volume pedal - 02/13/13 11:44 PM

Hello,

the problem is known. One possible solution:

Volume control with pedal

with the volume when the midi is such a thing.

When recording a sequence not a volume pedal is used at the beginning of a general volume command is written. Is also connected when playing no volume pedal, this becomes no more, because now the overall volume based on the position of the volume control of the instrument. However, a pedal connected then the current position is ignored and chosen instead the volume level of the sequencer (127).
To avoid this, you would have to delete the volume command.
It is located on the control track.
Press the button and select Step Sequencer-Rec.
Activate now confirm the control track (CTL) (usually in lane 8) and press OK.
Move the cursor to the first asterisk, which are now visible on the display. If the message in the information bar appears Control Exp = 127, delete this command with the DEL (Delete) on the edge of the display.
Leave the area by pressing the Sequencer Sequencer button and save the altered sequence from new. Reloading will notice that the volume increase is omitted at the beginning.
Posted by: Bert Aarts

Re: Volume pedal - 02/14/13 02:53 AM

Harry,
Thanks for your input but as mentioned in my previous post, to my opinion the problem is not related to sequencer songs as it also happens immediatly after switching on the keyboard and no sequence loaded.
Anyway I will test your suggestion later because I am going for a weeks vacation now.
Bert
Posted by: Bert Aarts

Re: Volume pedal - 02/24/13 10:46 AM

Harry,
You are correct. I checked a sequencer song that had the problem of the volume pedal and found the volume command. I removed the volume command and the problem was solved for that particular song. I will follow this procedure for my favourite songs.
The remaining problem now is that the problem occurs everytime I switch on the keyboard. For normal operation the main volume is set for maximum output and output is controlled by the pedal. If the pedal is not touched after switch on the volume is at maximum, independant of the position of the pedal. This means that I must not forget to touch the pedal before I touch a key. I assume this is not normal and I would like to solve this. Any ideas?
Bert