Finding pre-amp output in mini system - Page 2

jaycee · 8th May 2009, 03:59 AM

If it's a Denon of some age, they like to use STK hybrid modules. This will be a sizeable black chunky thing mounted to a heatsink.

chuck55 · 8th May 2009, 04:02 AM

"The chips (if indeed it is a chip amp) will be bolted to a big piece of metal called a heatsink ....."

Yup, the other two I found were bolted to a little piece of metal.
I finally found it. Amazing how they get these things together... and for so cheap.

It's not that great. Here it is:
SANYO STK 402-050

I see channel 1 and 2 but with all that other balony going on, can I really tap off those four wires without messing something else up? And if the amp is this average, how much better can the pre-amp be? Quiet enough for a LM3875 chipamp?

jaycee · 8th May 2009, 04:31 AM

To be honest I gutted a Denon microsystem, a DC30. They're nothing brilliant. The circuit was full of 4558 style opamps running on single voltage, and full of capacitors in the signal path, and plenty of BU4066 quad analog switches. The only good part was a motorised ALPS pot

What kind of preamp do you need? They're not that hard to make to be honest.

chuck55 · 8th May 2009, 09:06 AM

Hi Jaycee,
Well I'm disappointed but not too surprised. Ideally would like one with tone control at 100 / 10,000 hz and a remote control. A Djangos AVC sounds impressive too. Just don't want to go the confusing audiophile route like Adcom, Bel Canto, Placette, and on and on.....
Then there is this:
Pro-ject pre

It will have to work with this:

LM3875 gainclone

Looked into a bunch of passive pre kits with remote last year.

jaycee · 9th May 2009, 05:15 AM

Are you looking for pre-built, or will a kit type be OK?

If you're OK with kits and getting parts together, something like this works well:

http://sound.westhost.com/project97.htm

Rod only sells PCB's though, no parts...

Any kind of preamp will work with your Gainclone though.

chuck55 · 12th May 2009, 06:47 AM

Looks nice but I would prefer prebuilt and really need the remote.

chuck55 · 12th May 2009, 08:15 PM

Djangos look nice but expensive and supposed to be good for chip amp.

http://www.diyhifisupply.com/?q=cata...vcpreamplifier
http://www.diyhifisupply.com/?q=cata...vcpreamplifier

Django AVC preamp

I wonder what the difference is between AVC and TVC. Some had remote but i can't find them now.

jaycee · 13th May 2009, 08:21 AM

They look like typical overpriced audiophile hoodoo to me. I would argue a transformer based attenuator is going to be way more nonlinear than any pot, even a very bad one with gross channel imbalance. Sorry, but for $1K i can't help feeling you would be wasting your money.

If you don't need any gain for your sources, a good 50K Log ALPS "Blue Velvet" type pot will do, or indeed any good quality pot. A 4-way input selector can be made from any good quality 2-pole 4-way rotary switch.

If you wanted extra refinement, you could get some good quality DPDT signal relays and wire them up so that a 4-way rotary switch picks which relay to feed +12V to.

The only sore point here is that you want a remote. That means a microcontroller, which is going to be whats stopping you making one. I do belive though, there are a couple of kits about that are designed to control the motor of an ALPS motorised type pot that would do the job for you. I'm damn sure i've seen one on here that will do that, and even control some relays for source select.

Perhaps I should make one!

chuck55 · 13th May 2009, 05:18 PM

I hear you about the overpriced, audiophile stuff. Until you make one I found a few remotes preamps.
They question I have is will they drive the LM3875 chip amp. From what I've read the sound is thin and lacks dynamics. Even Peter Daniels uses a TVC for his Patek.

DIY Club:
http://eshop.diyclub.biz/product_inf...roducts_id=195

Decibel Audio K7:
http://www.decibelhifi.com.au/category4_1.htm

Dantimax.com has a Remote 1:
http://electronics.dantimax.dk/Kits/index.html

and Remote3 & 4:
http://electronics.dantimax.dk/Kits/...mps/index.html

AudioElectronics Supply has "overpriced" stuff:

http://www.audioelectronicsupply.com...prod_num=RVC_2

Altronics:
http://www.altronics.com.au/index.as...=item&id=K5026

So I've been searching, just not sure which to buy / if I want to make a kit.

jaycee · 14th May 2009, 09:48 AM

Again to be honest, hoodoo. The LM chip amps are easily driven by any preamp or source directly. If memory serves they have an input impedance of 22K. There is no black magic to a gainclone really. My self built one certainly has no problems.

The Remote1 kit looks good. Be aware that it's just a controller for a motorised pot, not a preamp. Control1 also looks good if you want to switch some relays for an input selector. It's a pity they dont do an integrated unit that has the features of both.

Control1 full kit for 37EUR isnt a bad price... be aware that you would have to buy the ALPS motorised pot, though.

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8th May 2009, 03:59 AM	#11
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	If it's a Denon of some age, they like to use STK hybrid modules. This will be a sizeable black chunky thing mounted to a heatsink.

8th May 2009, 04:02 AM	#12
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	"The chips (if indeed it is a chip amp) will be bolted to a big piece of metal called a heatsink ....." Yup, the other two I found were bolted to a little piece of metal. I finally found it. Amazing how they get these things together... and for so cheap. It's not that great. Here it is: SANYO STK 402-050 I see channel 1 and 2 but with all that other balony going on, can I really tap off those four wires without messing something else up? And if the amp is this average, how much better can the pre-amp be? Quiet enough for a LM3875 chipamp?

8th May 2009, 04:31 AM	#13
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	To be honest I gutted a Denon microsystem, a DC30. They're nothing brilliant. The circuit was full of 4558 style opamps running on single voltage, and full of capacitors in the signal path, and plenty of BU4066 quad analog switches. The only good part was a motorised ALPS pot What kind of preamp do you need? They're not that hard to make to be honest.

8th May 2009, 09:06 AM	#14
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	Hi Jaycee, Well I'm disappointed but not too surprised. Ideally would like one with tone control at 100 / 10,000 hz and a remote control. A Djangos AVC sounds impressive too. Just don't want to go the confusing audiophile route like Adcom, Bel Canto, Placette, and on and on..... Then there is this: Pro-ject pre It will have to work with this: LM3875 gainclone Looked into a bunch of passive pre kits with remote last year.

9th May 2009, 05:15 AM	#15
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Are you looking for pre-built, or will a kit type be OK? If you're OK with kits and getting parts together, something like this works well: http://sound.westhost.com/project97.htm Rod only sells PCB's though, no parts... Any kind of preamp will work with your Gainclone though.

12th May 2009, 06:47 AM	#16
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	Looks nice but I would prefer prebuilt and really need the remote.

12th May 2009, 08:15 PM	#17
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	Djangos look nice but expensive and supposed to be good for chip amp. http://www.diyhifisupply.com/?q=cata...vcpreamplifier http://www.diyhifisupply.com/?q=cata...vcpreamplifier Django AVC preamp I wonder what the difference is between AVC and TVC. Some had remote but i can't find them now.

13th May 2009, 08:21 AM	#18
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	They look like typical overpriced audiophile hoodoo to me. I would argue a transformer based attenuator is going to be way more nonlinear than any pot, even a very bad one with gross channel imbalance. Sorry, but for $1K i can't help feeling you would be wasting your money. If you don't need any gain for your sources, a good 50K Log ALPS "Blue Velvet" type pot will do, or indeed any good quality pot. A 4-way input selector can be made from any good quality 2-pole 4-way rotary switch. If you wanted extra refinement, you could get some good quality DPDT signal relays and wire them up so that a 4-way rotary switch picks which relay to feed +12V to. The only sore point here is that you want a remote. That means a microcontroller, which is going to be whats stopping you making one. I do belive though, there are a couple of kits about that are designed to control the motor of an ALPS motorised type pot that would do the job for you. I'm damn sure i've seen one on here that will do that, and even control some relays for source select. Perhaps I should make one!

13th May 2009, 05:18 PM	#19
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	I hear you about the overpriced, audiophile stuff. Until you make one I found a few remotes preamps. They question I have is will they drive the LM3875 chip amp. From what I've read the sound is thin and lacks dynamics. Even Peter Daniels uses a TVC for his Patek. DIY Club: http://eshop.diyclub.biz/product_inf...roducts_id=195 Decibel Audio K7: http://www.decibelhifi.com.au/category4_1.htm Dantimax.com has a Remote 1: http://electronics.dantimax.dk/Kits/index.html and Remote3 & 4: http://electronics.dantimax.dk/Kits/...mps/index.html AudioElectronics Supply has "overpriced" stuff: http://www.audioelectronicsupply.com...prod_num=RVC_2 Altronics: http://www.altronics.com.au/index.as...=item&id=K5026 So I've been searching, just not sure which to buy / if I want to make a kit.

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14th May 2009, 09:48 AM	#20
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Again to be honest, hoodoo. The LM chip amps are easily driven by any preamp or source directly. If memory serves they have an input impedance of 22K. There is no black magic to a gainclone really. My self built one certainly has no problems. The Remote1 kit looks good. Be aware that it's just a controller for a motorised pot, not a preamp. Control1 also looks good if you want to switch some relays for an input selector. It's a pity they dont do an integrated unit that has the features of both. Control1 full kit for 37EUR isnt a bad price... be aware that you would have to buy the ALPS motorised pot, though.