I've ordered a 15v version and will give that a try. It just seems like a smarter approach rather than making a bunch of adjustments further downstream.
Franken-Whammy. Still here. Poor thing.
Couldn't resist whipping in the XEN discrete regs again, this time just supplying the op-amp. The XEN regs are giving out stable +20.11 / -20.13. Input is around 21.5 so a small dropout.
Definitely yes, this works a treat. For once I actually heard a noticeable difference, I think the 994Enh likes a higher supply voltage, certainly things have opened up.
The CapMX is still knocking out a steady +/-18.5 V for the rest of the circuit, so running the regs and MX at the limit of their operating voltage.
Couldn't resist whipping in the XEN discrete regs again, this time just supplying the op-amp. The XEN regs are giving out stable +20.11 / -20.13. Input is around 21.5 so a small dropout.
Definitely yes, this works a treat. For once I actually heard a noticeable difference, I think the 994Enh likes a higher supply voltage, certainly things have opened up.
The CapMX is still knocking out a steady +/-18.5 V for the rest of the circuit, so running the regs and MX at the limit of their operating voltage.
Attachments
Probably the big part of the improvement comes from having separate supplies for the opamp and the "power" stage?
For this op-amp, yes for sure. It has definitely opened up the sound, I think the 994Enh comes alive with a bit more juice. This op-amp is a monster, blows anything else I have heard away. Hard to know what to write without the usual blah, blah but everything is better.
Very impressed with all the ancillary upgrades, CapMX, op-amp and regs are all excellent additions. This Whammy is a lot of fun and sounds lovely. The XEN regs might be one of the slickest little DIY audio designs ever. Brilliant things, should have asked for 20 boards.
I'm running on 18V transformer and everything else stock BOM. Reg heatsinks only get warm and isn't too hot. Maybe check the specs on the heatsinks first before using a smaller transformer too? Some has similar dimensions but different thermal conductivity/resistance.
2x18V transformers work well with 15regs+LED. 2x15V transformers work well with 15V regs. you can also use 2x18V transformers for 15V regs only too. But they will get hot, and i recomend to stick with origninal bias settings if you do so.
Can I use the Whammy with no volume pot and just use the digital attenuation on the DAC? So the Whammy has a straight line to the 1K input resistors.
I can't see a problem, the circuit just sees an attenuated signal. As long as the source sees a bit of impedance, in this case 3K3 series input on the RCA connectors and 1K across board inputs.
I can't see a problem, the circuit just sees an attenuated signal. As long as the source sees a bit of impedance, in this case 3K3 series input on the RCA connectors and 1K across board inputs.
Actually I would need to do this -
1. Adjust the pot to ideal volume.
2. Measure the resistance of pot.
3. Use R value across collector to Gnd?
1. Adjust the pot to ideal volume.
2. Measure the resistance of pot.
3. Use R value across collector to Gnd?
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What do you mean by "ideal volume". As in "ideal gain" or "ideal input inpedance? I noticed that some op amps have different behavior depending on input impedance (pot position), tested for costant output at different pot position/source voltage.
Should then op amp gain also be adjusted to have fully optimized system?
A good dac would be needed if one wanrs to control volume digitally... not very recommanded.
Should then op amp gain also be adjusted to have fully optimized system?
A good dac would be needed if one wanrs to control volume digitally... not very recommanded.
Of course!
Not entirely sure it would be any advantage to having the volume pot wide open, which is for all practical purposes the same as bypassed...
But remember if you adjust volume in digital you are throwing away bits and information in the digital realm, losing resolution and data. If you keep the digital level all the way up you can then attenuate the analog level (with the whammy’s pot) to a listening level that works for you.
There’s no right or wrong answer. In my experience and practice, I always have dac wide open and use the volume knob to adjust level, as this sounds best.
Not entirely sure it would be any advantage to having the volume pot wide open, which is for all practical purposes the same as bypassed...
But remember if you adjust volume in digital you are throwing away bits and information in the digital realm, losing resolution and data. If you keep the digital level all the way up you can then attenuate the analog level (with the whammy’s pot) to a listening level that works for you.
There’s no right or wrong answer. In my experience and practice, I always have dac wide open and use the volume knob to adjust level, as this sounds best.
Yeah, agreed. This is what I have been doing with the digital control maxed out and has been working well, may as well remove the digital attenuator as I rarely use it anyway. One input, fixed level.
The DACT ebay pot I have is playing up slightly, bit of scratching between increments and occasional balance drop out. You get what you pay for, they sound very decent when good.
No bother, as you were... 😉
Penmarker . . . what chassis did you use for your Whammy build and how did you do the front lettering? Front panel looks exceptional!
Volume control
I don't mean to digress. I used to believe that analog volume control is best. However, for my equipment, I changed my mind after using the digital volume control in ESS 32 bit DACs.
I may not be imagining it. Please see
http://www.esstech.com/files/3014/4095/4308/digital-vs-analog-volume-control.pdf
In slide 15 , I suppose we could argue with different numbers and tiny differences, but the points are valid. And yes, I realize they are trying to sell their equipment. 🙂
I don't mean to digress. I used to believe that analog volume control is best. However, for my equipment, I changed my mind after using the digital volume control in ESS 32 bit DACs.
I may not be imagining it. Please see
http://www.esstech.com/files/3014/4095/4308/digital-vs-analog-volume-control.pdf
In slide 15 , I suppose we could argue with different numbers and tiny differences, but the points are valid. And yes, I realize they are trying to sell their equipment. 🙂
#Aliexpress MYR 152.25 | 1907E Full Aluminum Enclosure / preamp case / Headphone amp box /AMP chassis
1907E Full Aluminum Enclosure / preamp case / Headphone amp box /AMP chassis|box amps|box boxcase case - AliExpress
The labels are laser engraved. They work better on the painted parts.
The button has a translucent plastic ring around it so I Jerry rigged the LED behind the ring just like Mark Johnson.
1907E Full Aluminum Enclosure / preamp case / Headphone amp box /AMP chassis|box amps|box boxcase case - AliExpress
The labels are laser engraved. They work better on the painted parts.
The button has a translucent plastic ring around it so I Jerry rigged the LED behind the ring just like Mark Johnson.
does the 22uf cap parallel to the 10k ohm form a LPF? i just realized mine were 10uf and having changed them i notice a significant difference in the sound.
Finally managed to get my opa1612aid working. Had my friend reflowed the solder joints for me. It seems the flux I used could possibly have some issues. Offset is now below 4mV both channels when headphones are not connected. But when headphones are connected the offset is weird.. When the volume knob is all the way down, offset for right channel is -110mV and left channel is -40mV. The offset approaches zero as the volume knob increases. Is this normal?
- Note this doesn't happens with my other opamps. Offset is close to 0 across the entire range of the volume knob
It runs really hot too! Almost too hot to touch after 2-3 seconds. Is that the case for you guys who's been playing with OPA1612aid? Pin 4 and 8 measures 16.2v and -16.2v (with 18v trannies).
- Note this doesn't happens with my other opamps. Offset is close to 0 across the entire range of the volume knob
It runs really hot too! Almost too hot to touch after 2-3 seconds. Is that the case for you guys who's been playing with OPA1612aid? Pin 4 and 8 measures 16.2v and -16.2v (with 18v trannies).
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