My two cents It's been my experience the starting with a complete kit offers some reassurance to builders with entry level or moderate experience like myself. Unless one has some advanced knowledge, there can be a lot of "Hunt and Peck" in parts selection. IMHO, most of the upgrades are not that expensive and each builder should decide if the safety factor is worth the extra dollars.
At the rate I going I won't be able to hang out my "Guru" shingle till around 2047.
Till then I'll probably lean toward starting with kits 
The thing that swayed me on the complete kit was the fact that I have 2 other DIY audio projects that I have not completed (and I started them months ago). One a tube amp 90% done and the other a AMB input/output selector - attenuator - Display processor at about 80% done. The AMD project requires several very small connctors to be built which I have yet to complete since I don't have the correct crimping tool. The tube amp just makes me nervous. With this kit I received it in the mail and had it working the next day. I remember spending quite a bit of time on mouser doing the "Hunt and Peck" portion my other 2 projects.
May be a stupid question but I have just received my 4398 board and:
The schematic show the 'analogue' section fed from a 15-0-15 supply with the CT grounded.
But no earth is shown on the 9-12V 'digital' ac supply. Should one of these also be grounded and if so, which of the two terminals? Or is is it just left to float, or does it pick up its reference voltage from the earth on the 'analogue' supply?
The schematic show the 'analogue' section fed from a 15-0-15 supply with the CT grounded.
But no earth is shown on the 9-12V 'digital' ac supply. Should one of these also be grounded and if so, which of the two terminals? Or is is it just left to float, or does it pick up its reference voltage from the earth on the 'analogue' supply?
Hi, I now use my pc with a USB SPDIF converter to supply my AK4396 dac.
I have just had a tinker and plugged the dac directly to my power amp.
I like the sound much better this way so would it be possible to put a volume pot in between the dac and power amp.
If this is no problem, what value would be best 50k, 100k.
My amp is the Linn LK280 which I believe has a strange input impedance. 3k ohms I believe
I have just had a tinker and plugged the dac directly to my power amp.
I like the sound much better this way so would it be possible to put a volume pot in between the dac and power amp.
If this is no problem, what value would be best 50k, 100k.
My amp is the Linn LK280 which I believe has a strange input impedance. 3k ohms I believe
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This is much more than is necessary, but may be helpful. Shielded Pot
Also - here is a simple diagram. SMD Pot - from eBay.
Also - here is a simple diagram. SMD Pot - from eBay.
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I have both of them and it's a toss-up. The Alps offers non-stepped operation but the 21 divisions on the SMD are more than adequate. The Alps is a heavier build but sounds a bit filtered when compared to the SMD. It is possible to fuse some of the resistors with excessive heat when attaching the leads to the inlets on the SMD pot.
If you plan to mount the pot directly on a PCB you need the Alps with pins. I haven't seen a motorized version of the SMD if you want remote control.
I lean toward the 10K SMD for it's clarity, but wouldn't hesitate buying the Alps Blue if the build/application required the physical features it offers.
The choice of 10K is matched to best operation with my particular power amp. You will need to select the value based on your system /amp specs..
If you plan to mount the pot directly on a PCB you need the Alps with pins. I haven't seen a motorized version of the SMD if you want remote control.
I lean toward the 10K SMD for it's clarity, but wouldn't hesitate buying the Alps Blue if the build/application required the physical features it offers.
The choice of 10K is matched to best operation with my particular power amp. You will need to select the value based on your system /amp specs..
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Hi,
I removed "The unbalancer" and tried connecting my AK4396 chip directly to the input of the amp without a capacitor. The output gives +2,5V DC, so I turned the bias of the driver tube -2,5V more to cancel it. It looses versatility, but not a pain for me. The input impedance is 200k.
The sound ROCKS! In such words, I don't want to have capacitors again!
The problem is, the gain is not enough. How much swing is the DAC supposed to give? I need at least 1,5V for my amp for full volume. The digital part is the famous ebay USB to I2S converter, tenor chip. The AKM4396 is I2S connected now.
I removed "The unbalancer" and tried connecting my AK4396 chip directly to the input of the amp without a capacitor. The output gives +2,5V DC, so I turned the bias of the driver tube -2,5V more to cancel it. It looses versatility, but not a pain for me. The input impedance is 200k.
The sound ROCKS! In such words, I don't want to have capacitors again!
The problem is, the gain is not enough. How much swing is the DAC supposed to give? I need at least 1,5V for my amp for full volume. The digital part is the famous ebay USB to I2S converter, tenor chip. The AKM4396 is I2S connected now.
Welcome to the no capacitor club
I also gave up on coupling capacitors after I heard the DAC with output transformers and straight on Aleph Mini - no caps...
As for AK4396 output voltage - per datasheet in typical conditions it should give 5,6Vpp (~1,9Vrms) between it's differential outputs...
Keep in mind that both differential outputs are at +2,5VDC and you shouldn't connect either one on GND, you don't want current flowing to ground on a voltage-out DAC...
And also, if you're using only one of the diff. outputs you will get half the output signal - this could be your problem - assumed you were using "The unbalancer" to get SE output...
A little more detailed explanation of your output connections would help locate the problem...
I also gave up on coupling capacitors after I heard the DAC with output transformers and straight on Aleph Mini - no caps...
As for AK4396 output voltage - per datasheet in typical conditions it should give 5,6Vpp (~1,9Vrms) between it's differential outputs...
Keep in mind that both differential outputs are at +2,5VDC and you shouldn't connect either one on GND, you don't want current flowing to ground on a voltage-out DAC...
And also, if you're using only one of the diff. outputs you will get half the output signal - this could be your problem - assumed you were using "The unbalancer" to get SE output...
A little more detailed explanation of your output connections would help locate the problem...
This is the schematic:
Schematic
The datasheet also says that the max output capacitance to drive must be 25pF. If it's true, this worries me very much. No way to drive triode stuff with high gain.
I'm using the positive lead as illustrated. Ignore the stuff in color.
Can you recommend output transformers that will make the DAC happy?
Schematic
The datasheet also says that the max output capacitance to drive must be 25pF. If it's true, this worries me very much. No way to drive triode stuff with high gain.
I'm using the positive lead as illustrated. Ignore the stuff in color.
Can you recommend output transformers that will make the DAC happy?
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Well, the problem is that you're using only one differential output, therefore the low signal, you should be getting a little below 1Vrms with that setup...
Transformers on the output would solve your problem, however it's a rather expensive solution, you won't get anything good below 100$...
UTC - very good, but a little overpriced
Tamura - a few good ones pop up on ebay once in a while
Sowter...
Lundahl...
any 600ohm:600ohm with good specs...
As for valves, I have no experience with them, so I'm not going to be of much use...
Just an observation, I could be wrong, but; if you use a push-pull valve amplifier you could use both of the DAC outputs.?
Also the "triode stuff with high gain" you mentioned, what would be the capacitance compared to the datasheet max. value?
Transformers on the output would solve your problem, however it's a rather expensive solution, you won't get anything good below 100$...
UTC - very good, but a little overpriced
Tamura - a few good ones pop up on ebay once in a while
Sowter...
Lundahl...
any 600ohm:600ohm with good specs...
As for valves, I have no experience with them, so I'm not going to be of much use...
Just an observation, I could be wrong, but; if you use a push-pull valve amplifier you could use both of the DAC outputs.?
Also the "triode stuff with high gain" you mentioned, what would be the capacitance compared to the datasheet max. value?
I may not be reading this dialog correctly, but I have had excellent results combining this DAC with a JC-2 preamp. The goal for some may be to avoid using a pre for gain but it is a good sounding solution. The combination provides more gain than I could ever use on some pretty large speakers.
I have also gone straight from DAC to power amp with PC control and a simple discrete pot volume control. All three approaches have proven functional and enjoyable.
I have also gone straight from DAC to power amp with PC control and a simple discrete pot volume control. All three approaches have proven functional and enjoyable.
Well it is a "little bit" out of the specs, but I wouldn't worry too much - it should work OK...