chromenuts,
Besides the CD transport you say is too loud, what other inputs to you use with the dac? A computer? If so, do you have the volume control turned down pretty low in the computer so as to keep the preamp volume control in the range where you want it?
Besides the CD transport you say is too loud, what other inputs to you use with the dac? A computer? If so, do you have the volume control turned down pretty low in the computer so as to keep the preamp volume control in the range where you want it?
I retested my current digital sources today.
I am now using a Mac Mini connected to the SMSL DAC via Toslink for anything I’ve downloaded or felt compelled to rip from my CD collection.
The transport is connected to the SMSL via SPDIF coaxial.
I loaded a CD in the transport that I have ripped into my library on the Mac as a AIFF lossless file. No special software, just iTunes right now.
I made sure the software volume control in iTunes was set to maximum.
After cueing up the same track on the computer and transport I tried switching between the two sources several times.
It appears that when the software volume is set to maximum level in iTunes that I do in fact get what sounds like the same volume level as the transport playing the same material off CD.
I’m surprised to make this discovery as I don’t remember lowering the volume in any of the computer software when I had made this comparison previously.
Perhaps this is because there is a default setting in the software which sets the volume in the middle of its range?
I have not been using a computer as a source for very long and it was not a habit of mine to adjust the volume level in software.
The level on my preamp still has to be turned down very low for both sources.
So it appears the problem is that the DAC has an output level that is too high for my system.
I was not able to measure the actual V p-p at the output of the DAC because I don’t have a signal I can use that would give me a stable reading...only music.
I’m not sure it matters at this point. I’m in the same boat I was in previously when I was trying to match the gain of my system to my analog source. I added Jensen transformers to my DCB1 based preamp because there wasn’t enough gain. Now there’s too much for my digital sources.
I am now using a Mac Mini connected to the SMSL DAC via Toslink for anything I’ve downloaded or felt compelled to rip from my CD collection.
The transport is connected to the SMSL via SPDIF coaxial.
I loaded a CD in the transport that I have ripped into my library on the Mac as a AIFF lossless file. No special software, just iTunes right now.
I made sure the software volume control in iTunes was set to maximum.
After cueing up the same track on the computer and transport I tried switching between the two sources several times.
It appears that when the software volume is set to maximum level in iTunes that I do in fact get what sounds like the same volume level as the transport playing the same material off CD.
I’m surprised to make this discovery as I don’t remember lowering the volume in any of the computer software when I had made this comparison previously.
Perhaps this is because there is a default setting in the software which sets the volume in the middle of its range?
I have not been using a computer as a source for very long and it was not a habit of mine to adjust the volume level in software.
The level on my preamp still has to be turned down very low for both sources.
So it appears the problem is that the DAC has an output level that is too high for my system.
I was not able to measure the actual V p-p at the output of the DAC because I don’t have a signal I can use that would give me a stable reading...only music.
I’m not sure it matters at this point. I’m in the same boat I was in previously when I was trying to match the gain of my system to my analog source. I added Jensen transformers to my DCB1 based preamp because there wasn’t enough gain. Now there’s too much for my digital sources.
Which is a very common problem.
You just need to attenuate the audio feed as I detailed earlier and unfortunately it really is by trial and error to get the subjective right.
chromenuts,
Good news then! All you need is a stereo analog attenuator between your dac analog output and your preamp input. Do you need help figuring that out, or do you feel comfortable proceeding on your own from this point?
Good news then! All you need is a stereo analog attenuator between your dac analog output and your preamp input. Do you need help figuring that out, or do you feel comfortable proceeding on your own from this point?
I’m not excited about having another attenuator in my signal path.
My goal with my next preamp was to eliminate pots. I’ve invested in one of Zen Mods Iron Pumpkin Pre kits along with the Turtle AVC.
I’m not sure how soon I will get that together. It has variable gain settings. I can actually set them up to be switchable for both channels on the fly.
I was thinking of using a pot to try and find the level of attenuation I want with the DAC and then measure and try to mimic the resistance with some Caddock MK or similar. Any guidance on that?
The other option I have is to go back into the DCB1 and add an output that bypasses the transformers and drops about 6dB of gain.
That’s a bit of a crap shoot (and work) as I have no idea if it’s close to what I need or how to calculate it.
If I want to use a test CD to take a Vp-p measurement at the output of the DAC, what signal is the best to use?
My goal with my next preamp was to eliminate pots. I’ve invested in one of Zen Mods Iron Pumpkin Pre kits along with the Turtle AVC.
I’m not sure how soon I will get that together. It has variable gain settings. I can actually set them up to be switchable for both channels on the fly.
I was thinking of using a pot to try and find the level of attenuation I want with the DAC and then measure and try to mimic the resistance with some Caddock MK or similar. Any guidance on that?
The other option I have is to go back into the DCB1 and add an output that bypasses the transformers and drops about 6dB of gain.
That’s a bit of a crap shoot (and work) as I have no idea if it’s close to what I need or how to calculate it.
If I want to use a test CD to take a Vp-p measurement at the output of the DAC, what signal is the best to use?
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According to all I've seen online there is nothing unusual about the M8/M8A. It has the standard 2Vrms output, so 0dB should yield 2V rms
You could take a double gang pot, say, maybe in the range of 1k to 10k. Then wire it up like a stereo voltage divider so you can dial in the exact attenuation you want. Once you find that out you could use fixed resistors to give the same division ratio.
Yes...I’ve read Papa’s comments in the B1 article about gain. It is part of the reason I decided to pursue the DCB1 as a preamp.
I had originally decided my DIY system should take the approach of simplicity wherever possible. This was especially true of speakers as I did not want to deal with the complexities of passive crossovers. I chose to utilize high sensitivity fullrange drivers in front horns. I currently use a Lowther DX3/Oris 200 horn combo. They are driven by my F2J mono block clones.
I eventually expanded the system with a B5 active crossover and some bass panels modeled after PaPa’s SLOB article that I drive with some old bridged Rotel HT amps. The very bottom is fudged with some support below 75Hz from an active sub.
Everything was working pretty well with my system until I decided I wanted to pursue experimenting with MC cartridges. MM carts were not a problem with the phono amp I was using. My analog source with MM was close to any CD players I was using as far as output level...but slightly lower.
Keeping the volume at 9 o’clock was a compromise that allowed all my sources to be listened to in a quieter relaxed manner. In order to get the system to “sing” at a more enthusiastic level with my analog source I had to turn it up to about 12 or 1 o’clock. Whereas a CD player would get to the same level closer to 10 o’clock.
MC carts struggled more even with the additional head amp I was using that was supposed to give me about 26dB of gain.
To be able to get to the same levels I was listening to previously with MM carts I needed to add the Jensen transformers to the preamp to pick up the 6dB of gain.
This obviously has made finding a balance with my current digital sources a bit more difficult.
I have other phono amp projects in que, but I’m not sure how long it will be before I can try and build something that will match MC carts better to the system.
As I mentioned, I’m currently trying to put together a TDA1541A DAC based on Ryan’s D3 board. I’m hoping the option of using only a IV resistor may work better with my system.
I had originally decided my DIY system should take the approach of simplicity wherever possible. This was especially true of speakers as I did not want to deal with the complexities of passive crossovers. I chose to utilize high sensitivity fullrange drivers in front horns. I currently use a Lowther DX3/Oris 200 horn combo. They are driven by my F2J mono block clones.
I eventually expanded the system with a B5 active crossover and some bass panels modeled after PaPa’s SLOB article that I drive with some old bridged Rotel HT amps. The very bottom is fudged with some support below 75Hz from an active sub.
Everything was working pretty well with my system until I decided I wanted to pursue experimenting with MC cartridges. MM carts were not a problem with the phono amp I was using. My analog source with MM was close to any CD players I was using as far as output level...but slightly lower.
Keeping the volume at 9 o’clock was a compromise that allowed all my sources to be listened to in a quieter relaxed manner. In order to get the system to “sing” at a more enthusiastic level with my analog source I had to turn it up to about 12 or 1 o’clock. Whereas a CD player would get to the same level closer to 10 o’clock.
MC carts struggled more even with the additional head amp I was using that was supposed to give me about 26dB of gain.
To be able to get to the same levels I was listening to previously with MM carts I needed to add the Jensen transformers to the preamp to pick up the 6dB of gain.
This obviously has made finding a balance with my current digital sources a bit more difficult.
I have other phono amp projects in que, but I’m not sure how long it will be before I can try and build something that will match MC carts better to the system.
As I mentioned, I’m currently trying to put together a TDA1541A DAC based on Ryan’s D3 board. I’m hoping the option of using only a IV resistor may work better with my system.
Unless you have an old TDA1541A you have been saving for years, or know somebody who has, chances of finding a real one are very slight.
I don't understand the zeal for the 9:00 position of the main volume pot. Pretty sure none of my rigs have ever needed that low of a setting -- unless it was just 'background music level'.
Was the 'gain' the only reason you fitted the Jensens? You didn't have a ground loop or other difficult issue to solve? I would be loath to accept the many other shortcomings of a transformer without a darned good reason. ('Gain' doesn't qualify. And sorry, but it isn't gain by the normal definition since it is only a voltage increase.😉)
Sure enjoyed your 'raffle' the other day. Thanks again for that.
Cheers
Was the 'gain' the only reason you fitted the Jensens? You didn't have a ground loop or other difficult issue to solve? I would be loath to accept the many other shortcomings of a transformer without a darned good reason. ('Gain' doesn't qualify. And sorry, but it isn't gain by the normal definition since it is only a voltage increase.😉)
Sure enjoyed your 'raffle' the other day. Thanks again for that.
Cheers
@Markw4 Yes I have a NOS sealed in packaging TDA1541A. I also have two additional TDA1541A made in Taiwan that I sourced from a reputable seller in the forum. In addition, I have two ROTEL 855 that have issues and I could harvest chips from.
@rfbrw Yes, it would seem a phono stage or step up with higher gain for my MC setup is needed. Perhaps then the gain from the transformers wouldn’t be needed.
At the time I was trying to originally get things to work building another phono amp was not a realistic option. I had already spent money on the head amp, MC cart and a new arm that would have enough mass to match its compliance. I was also trying to maintain the flexibility of using MM carts. The balancing act didn’t work out.
@Rick PA Stadel There was no real goal in achieving a specific gain that would allow for a 9 o’clock position with the pots, it just turned out that way. I would say it is a level that falls into the “background-ish” category...not too loud or too quiet with either source.
The only issue I had noticed using the preamp previously is that there was some hum when I tried connecting it to my Quicksilver Horn Mono Amps. That was corrected by adding a central ground strap to my Hypnotize board as recommended by Salas...actually he gave me guidance on adding a safety ground which I incorporated into the board the transformers are mounted on. There was no issue with other amps I had built and used with the preamp previously. I don’t use the Horn Monos much anymore.
Using the transformers as a way of picking up needed gain was a simple solution that presented itself in a time of need. It was also reasonably within my skill level and understanding to implement.
However, I would be lying if I were to say I noted a decline in the sound quality of my system in any way. I had read various opinions about the subject concerning ringing and other possible issues. I was able to pick up the “gain” I needed to get the MC to sing better and my 53 year old ears are probably incapable of hearing any negative effects.
Glad about the reaction to the raffle. I benefited as much as you guys and the winner. It feels good to “Pay It Forward”.
@rfbrw Yes, it would seem a phono stage or step up with higher gain for my MC setup is needed. Perhaps then the gain from the transformers wouldn’t be needed.
At the time I was trying to originally get things to work building another phono amp was not a realistic option. I had already spent money on the head amp, MC cart and a new arm that would have enough mass to match its compliance. I was also trying to maintain the flexibility of using MM carts. The balancing act didn’t work out.
@Rick PA Stadel There was no real goal in achieving a specific gain that would allow for a 9 o’clock position with the pots, it just turned out that way. I would say it is a level that falls into the “background-ish” category...not too loud or too quiet with either source.
The only issue I had noticed using the preamp previously is that there was some hum when I tried connecting it to my Quicksilver Horn Mono Amps. That was corrected by adding a central ground strap to my Hypnotize board as recommended by Salas...actually he gave me guidance on adding a safety ground which I incorporated into the board the transformers are mounted on. There was no issue with other amps I had built and used with the preamp previously. I don’t use the Horn Monos much anymore.
Using the transformers as a way of picking up needed gain was a simple solution that presented itself in a time of need. It was also reasonably within my skill level and understanding to implement.
However, I would be lying if I were to say I noted a decline in the sound quality of my system in any way. I had read various opinions about the subject concerning ringing and other possible issues. I was able to pick up the “gain” I needed to get the MC to sing better and my 53 year old ears are probably incapable of hearing any negative effects.
Glad about the reaction to the raffle. I benefited as much as you guys and the winner. It feels good to “Pay It Forward”.