I have started a amp build using six of the Coldamp Sonora S250 modules and one SPS80 PSU.
I was hoping to have progressed much further but life has intervened & slowed progress considerably.
To save some funds I have emptied an old Yamaha amp case I have & am using that in the short term (probably long term)
I have drawing a schematic, for sorts that has been checked by Sergio, who has been VERY helpful.
The modules are mounted on the back side of a piece of aluminium checker plate, which turns out not to be as flat as you may hope, so I will use some thermal tape to mount them should they heat up too much. I have salvaged the heat sinks from the Yamaha & will mount those on the checker plate. I will need to build a new front panel which will be timber & aluminium & a new back panel, I have manages to scrounge all of the aluminium & have plenty of timber to choose from. As far as I can tell I have all of the bits I need now all of I need is some more time on the weekends.
There is one thing that I would still like to do, that is have a global (One knob to control all channels) volume control. The amp will be feed by a Squeezebox Touch via a MiniDSP so I can use the Touch for general volume control, but would like to be amp to set the volume to a maximum level manually. Also a balance control would be useful.
Oh, I am a beginner at all of this, just so you know.
Any ideas on the best way to apply volume and balance control over six channels?
I was hoping to have progressed much further but life has intervened & slowed progress considerably.
To save some funds I have emptied an old Yamaha amp case I have & am using that in the short term (probably long term)
I have drawing a schematic, for sorts that has been checked by Sergio, who has been VERY helpful.
The modules are mounted on the back side of a piece of aluminium checker plate, which turns out not to be as flat as you may hope, so I will use some thermal tape to mount them should they heat up too much. I have salvaged the heat sinks from the Yamaha & will mount those on the checker plate. I will need to build a new front panel which will be timber & aluminium & a new back panel, I have manages to scrounge all of the aluminium & have plenty of timber to choose from. As far as I can tell I have all of the bits I need now all of I need is some more time on the weekends.
There is one thing that I would still like to do, that is have a global (One knob to control all channels) volume control. The amp will be feed by a Squeezebox Touch via a MiniDSP so I can use the Touch for general volume control, but would like to be amp to set the volume to a maximum level manually. Also a balance control would be useful.
Oh, I am a beginner at all of this, just so you know.
Any ideas on the best way to apply volume and balance control over six channels?
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Hi,
Nice setup, although you should make sure that you use a good aluminium base that is flat and 2-3mm thick. Using thermal tape is not a good idea, it is much easier to get the proper alu panel (some local shop can cut it for you to your desired dimensions). Things that are well done from the start always work much better!
As for the global volume control, what is your sound source, a 5.1 receiver or something like that? Otherwise, if it is stereo and you are going to triamp, for example, the best thing is to use a stereo volume control before splitting at the filters (and possibly add a smal adjustment to each channel individually at the POT header so you can adjust relative levels easily).
Nice setup, although you should make sure that you use a good aluminium base that is flat and 2-3mm thick. Using thermal tape is not a good idea, it is much easier to get the proper alu panel (some local shop can cut it for you to your desired dimensions). Things that are well done from the start always work much better!
As for the global volume control, what is your sound source, a 5.1 receiver or something like that? Otherwise, if it is stereo and you are going to triamp, for example, the best thing is to use a stereo volume control before splitting at the filters (and possibly add a smal adjustment to each channel individually at the POT header so you can adjust relative levels easily).
The amp will be feed by a Squeezebox Touch via a MiniDSP which will split the signal (tweeter left & right, Mid Left & Right, Bass Left & Right)& to the six amp modules & then to three drivers in each active speaker.
The MiniDSP will look after the driver levelling,
Ideally I would like the volume control as a single knob on the amp case.
I have found this on ebay ALPS 6-gang motorized Potentiometer RK16816MG 10K Pot - eBay (item 350371173403 end time Feb-26-11 08:03:49 PST) would it be the go, then I can have a remote if I want.
David
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Then things are a bit more difficult.
We are also designing a DSP board (to be available by mid of this year I hope), and I am almost sure we use the same family of chips than MiniDSP. Some of these chips have pins associated to a 8 or 10-bit A/D converter. They can be used to connect a DC voltage to control anything inside, for example the volume of all the channels (this require proper software in the board, of course).
Check the datasheet or ask the manufacturer if they can offer this possibility, and then you can use a simple voltage reference and single potentiometer to control the volume of all channels inside the DSP processor.
Just an idea, hope this helps.
We are also designing a DSP board (to be available by mid of this year I hope), and I am almost sure we use the same family of chips than MiniDSP. Some of these chips have pins associated to a 8 or 10-bit A/D converter. They can be used to connect a DC voltage to control anything inside, for example the volume of all the channels (this require proper software in the board, of course).
Check the datasheet or ask the manufacturer if they can offer this possibility, and then you can use a simple voltage reference and single potentiometer to control the volume of all channels inside the DSP processor.
Just an idea, hope this helps.
I can add a volume control to the MiniDSP, but the things I have read about the volume control is at the moment it doesn't work as well as one might hope.
Is there a problem with adding a six gang volume control to the amp?
What problems have you read about? Just curious since I've been testing the minidsp for some time now, using a potmeter to control the minidsp volume. To me it seems to work great.
I guess you will need 2 minidsp units to have 2x3 channels. I think you could use a single-gang volume to control both if they have the same powersupply. If so (probably you should check this), you won't have any problem with level difference between channels.
I guess you will need 2 minidsp units to have 2x3 channels. I think you could use a single-gang volume to control both if they have the same powersupply. If so (probably you should check this), you won't have any problem with level difference between channels.
Nice project david you are re-using a electronic enclosure. Can be perfect with new front and en plate and wooden side panels.
That volume control shout be OK. You can use a wire to control the motor and have a remote control by wire or use IR-wireless-control with eletronics to control the motor.
But after this you have to build 6 loudspeaker poor guy
That volume control shout be OK. You can use a wire to control the motor and have a remote control by wire or use IR-wireless-control with eletronics to control the motor.
But after this you have to build 6 loudspeaker poor guy
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I have 2 x DSP & 2 x Digi, but I intend to reconfigure to 1 x Digi & 2 x DSP. The problem I have read about are on their forum, so if you go there & do a search you will find issues about tapers etc.
The main issue for me is I want to put on the amp, not the DSP.
Nice project david you are re-using a electronic enclosure. Can be perfect with new front and en plate and wooden side panels.
That volume control shout be OK. You can use a wire to control the motor and have a remote control by wire or use IR-wireless-control with eletronics to control the motor.
But after this you have to build 6 loudspeaker poor guy
I might use in manually first & add a remote if so desired.
I would like an easy way to control the balance though say one knob, any thoughts on the best way of doing that?
I think that kind 6X potmeter doesn't exsist.
you need a lineair pot with + left and +right on the rightsite. So in the middle both channels are the same . Turn left left increases and turn right right increases.
Balance control is not done in a high qaulity set. The only thing you need is bass control IMO to compensate the radiation patern to room size.
The reason I wanted the balance control is some of the albums I play seem to be loop sided, I assume it is the way they are recorded, but I find it annoying. If it doesn't exist, 6 channel balance that is, that's fine I will go without
ssanmor
Is this the correct potentiometer to buy for your modules?
ALPS 6-gang motorized Potentiometer RK16816MG 10K Pot - eBay (item 350371173403 end time Feb-26-11 08:03:49 PST)
David
I guess the possible downside of all that extra wire to connect the potentiometer is I stand a greater chance of inducing some noise into the system.
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Check the needle and tuning of arm element.The reason I wanted the balance control is some of the albums I play seem to be loop sided, I assume it is the way they are recorded, but I find it annoying. If it doesn't exist, 6 channel balance that is, that's fine I will go without
Hmmm, what does that mean?
I know, you think I am playing records, I don't own any records, could never stand all the extra noise & work that came along with them. It's all CD's ripped to the computer & played via the squeezebox.
I haven't owned a black disc for about 27years.
I'll have to admit I would like to hear what a good system playing a record sounds like.
David
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Playing records is a ritual and see it spinning just fun.Hmmm, what does that mean?
I know, you think I am playing records, I don't own any records, could never stand all the extra noise & work that came along with them. It's all CD's ripped to the computer & played via the squeezebox.
I haven't owned a black disc for about 27years.
I'll have to admit I would like to hear what a good system playing a record sounds like.
David
And with a good record and preamp you can get a extra dimension that isn't found in a cd player jet.
I have a colleague how digitalized records is also a real audiophile and the specious analogue sound is saved on the cd so I contradict my self by this statement.
That digitized analog record shows more 3D detail than a normal cd recording.
When you search on ebay there are several low cost stepped attentuators to find.
Balance XLR 23 Stepped Attenuator Potentiometer 50K Log - eBay (item 270698430393 end time Feb-26-11 15:17:22 PST)
Balance XLR 23 Stepped Attenuator Potentiometer 50K Log - eBay (item 270698430393 end time Feb-26-11 15:17:22 PST)
The same type switch i use. (not the most luxuries step) it works.
24 Step Attenuator Volume Control Pot Log 100K Stereo - eBay (item 260636624590 end time Mar-13-11 21:07:24 PDT)
24 Step Attenuator Volume Control Pot Log 100K Stereo - eBay (item 260636624590 end time Mar-13-11 21:07:24 PDT)
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