Thanks again! Ill post some pics later next week after i grab device from office for mods.
Sorry about the picture.
Here is a link to the Turn ON/OFF Suggested Sequence. It can be found on page 9, figure 16: http://www.st.com/web/en/resource/technical/document/datasheet/CD00000017.pdf
From reports for those who did the cinemags it took a modded amp which was great to world class. It has to do a lot with allowing use of differential inputs to reside common mode noise. The "blacks are blacker" 🙂.
Agreed that $120 mod on a $15 amp that has no mods is crazy. But if you have done the typical $25 worth of mods already and there is not much left to do then try it. Edcor makes a $30 trafo - I think it works well too but ultimate performance not as high as Cinemags.
With all mods in and Cinemag, the amp can indeed best a first watt amp as has been described earlier by another member.
Agreed that $120 mod on a $15 amp that has no mods is crazy. But if you have done the typical $25 worth of mods already and there is not much left to do then try it. Edcor makes a $30 trafo - I think it works well too but ultimate performance not as high as Cinemags.
With all mods in and Cinemag, the amp can indeed best a first watt amp as has been described earlier by another member.
Another benefit of using transformers for input decoupling is that it's an easy way to solve the power on/off pop issue. In this particular regard, the Edcors are just as good as the Cinemags.
Regarding the pop issue how to implement a switch button to avoid the power on/of pop on the Sure board?
Short STBY to GND. That will put the amp in shutdown mode. Before I got the gmarsh Weiner board, this is exactly what I did with a simple SPST switch. Process was: put amp in shutdown mode, power on, listen to music, shutdown, power off. Depending on how energy conscious you are, you could just leave it powered on all the time and use the shutdown switch to enable/disable it.
Instead of cinemags you could just use balanced inputs, run the twisted pair through a toroid choke, then a lowpass filter at 20khz before input caps.
Cleans up the incoming signal much cheaper, without what the cinemags "add" to the sound.
Cleans up the incoming signal much cheaper, without what the cinemags "add" to the sound.
Most people don't have balanced sources - unless they are using pro audio gear as preamp. The trafo allows unbalanced (like RCA) get split into balanced and bypass the input cap. That skipping the cap apparently improves signal transparency (so we are told).
I personally don't believe the hype with cinemags, nor other makes. They are transformers, which are non-linear to the signal, and will add in low order harmonics. They are coloring the sound by trying to replicate a valve/tube amp sound. If you want a valve/tube amp then build one instead of replicating one!
With the balanced input, most DACS are easy mod to balance output, even a stereo headphone socket and lead and be cut and have connectors fitted which will work 4 balanced inputs. This issue is less complicated than the standby mod.
Instead of bypassing the input cap, set the value so the created RC input is the low bass freq slope wanted at the speaker xo. You can then eliminate the low freq not needed by the speaker from even troubling the amp chip or the output filter.....need only the hpf for the tweeter in xo, driving the larger cone straight from amp outputs. Improve efficiency a little!
Last edited:
Must add the last RC value suggestion is only relevant if driver a full range, would still need the lpf at xo.
Actually, now that you mention it... I originally used a SPST switch, but then decided I wanted an LED. But, you probably want the LED off when the amp is on standby (and the LED on when not on standby). So for this, you can use a double pole, single throw (DPST) switch: in position 1, one circuit is open (LED), other is closed (STBY); in position 2, it's the opposite.
It's Alive!
Found a reasonable wooden box at the local 1$ store. Works well.
The thing; Blu /black Board, works surprisningly well, albeit perhaps a bit Tizzy.. but good detail and Decent bass. Early days yet though.
Power Supplies, from 12V to 24V makes Not a Whit of Audible difference. At least on My Wee MarkAudio Full rangers.
Power up ' Scrotch ' Is of concern. Nothing at turn off tho.
This thing is Sensitive to input RF(?) pickup. I foolishly didn't twist Or Fit shielded wires from input/rca's to Alps to PCB..
Each leg being ~1" long.
Wasn't an issue with 2020's. I will deal with it 🙂
Sounds?? Similar to my Yuan Jing Ta 2020 pcb/amp which I've been using for garage tunes these last couple of years.
Small audible differences, if any actually, when A/B'd.
That's not a complaint, just a reference point.
Tripath Chips, when either Genuine OR passably mfg'd Fakes ..Are.. surprisingly Good. Too many(most?) are sad copies tho.
Note that virtually Every part on the Yuan Jing ta 2020 pcb IS Fake, including the "wima's" .
Replacing those with 'Genuine' same value bits, gave Audible improvement 😉.
Wonder if similar shenanigans are present with This 3116 Yuan Jing??
PS;
without removing the Resistors that control/set Gain( to read their silkscreened R) Can anyone tell me what they are.. so I can just snip a lead on the offending one (trying for 20db gain) 😱
Found a reasonable wooden box at the local 1$ store. Works well.
The thing; Blu /black Board, works surprisningly well, albeit perhaps a bit Tizzy.. but good detail and Decent bass. Early days yet though.
Power Supplies, from 12V to 24V makes Not a Whit of Audible difference. At least on My Wee MarkAudio Full rangers.
Power up ' Scrotch ' Is of concern. Nothing at turn off tho.
This thing is Sensitive to input RF(?) pickup. I foolishly didn't twist Or Fit shielded wires from input/rca's to Alps to PCB..
Each leg being ~1" long.
Wasn't an issue with 2020's. I will deal with it 🙂
Sounds?? Similar to my Yuan Jing Ta 2020 pcb/amp which I've been using for garage tunes these last couple of years.
Small audible differences, if any actually, when A/B'd.
That's not a complaint, just a reference point.
Tripath Chips, when either Genuine OR passably mfg'd Fakes ..Are.. surprisingly Good. Too many(most?) are sad copies tho.
Note that virtually Every part on the Yuan Jing ta 2020 pcb IS Fake, including the "wima's" .
Replacing those with 'Genuine' same value bits, gave Audible improvement 😉.
Wonder if similar shenanigans are present with This 3116 Yuan Jing??
PS;
without removing the Resistors that control/set Gain( to read their silkscreened R) Can anyone tell me what they are.. so I can just snip a lead on the offending one (trying for 20db gain) 😱
Last edited:
He
I think you are making assumptions about transformers adding distortion to sound tube like. Properly designed signal transformers are used for impedance matching critical instrument amps in research and there is not reason one can't be made low distortion for audio. If you look at the specs of the $11 Edcor UMM9-PC that would be used, it has a quoted THD of less than 0.05% HD at 1kHz and frequency range of 20Hz to 20kHz.
https://www.edcorusa.com/umm-series-2
I think you are making assumptions about transformers adding distortion to sound tube like. Properly designed signal transformers are used for impedance matching critical instrument amps in research and there is not reason one can't be made low distortion for audio. If you look at the specs of the $11 Edcor UMM9-PC that would be used, it has a quoted THD of less than 0.05% HD at 1kHz and frequency range of 20Hz to 20kHz.
https://www.edcorusa.com/umm-series-2
Last edited:
I agree - it seems to be a popular old wives' tale on here that adding a trafo adds distortion and tube lovers love the sound of distortion.
Certainly adding a trafo to the input my classD amp (a TDA8932) made the sound more 'tubey' but that's from the removal of common-mode noise rather than the addition of distortion.
With the right cores and drive techniques (zero or negative output impedance buffers) trafos can have vanishingly low distortion. Otherwise Audio Precision wouldn't have used one on the signal generator output for the analyser I used for several years.
Move the discussion along Boys.
Input Tx's are a Non Starter on a Bottom Feeder PCB/amp.
Like 'em? then Fit them.. Issue over and done with.
Input Tx's are a Non Starter on a Bottom Feeder PCB/amp.
Like 'em? then Fit them.. Issue over and done with.
A quote from Jensen transformers " Unlike electronic circuits that distort when the incoming signal level exceeds the rail voltage or power limits, transformers saturate. The saturation rounds off or smoothes the transients, creating a natural limiting effect that is often referred to as vintage sounding. It is no winder… vintage audio gear generally employ transformers."
And there are many other highly acclaimed audio designers having clearly shown what "distortion" they introduce.
I didn't use "distortion". I said they ADDED to the sound. As I've spent too many dark hours chipping away OB boards to reduce/remove as much of their added harmonics as possible, I wouldn't want to go adding more in before the amps even had a crack at the track!!
It's all personal preference in audio. As I said, I don't rate them.