Salas,
I have a few boards (populated and SMD, but I guess I can change some parts if needed) with r-2r ladder volume control and was wondering if those will work with the preamp. As these are ladder and they have a resistor you can use to match your pre Rin, I was wondering if those should work. Could you please take a look at this schematics?
I have a few boards (populated and SMD, but I guess I can change some parts if needed) with r-2r ladder volume control and was wondering if those will work with the preamp. As these are ladder and they have a resistor you can use to match your pre Rin, I was wondering if those should work. Could you please take a look at this schematics?
Attachments
It should work. Determine output resistance range as 0-5k roughly. There are online tools for calculating logarithmic ladder attenuators.
Thank you! The board as is says that Rout is 6 Ohm-4.7 kOhm. R16/R32 are supposed to be calculated using this formula R = 10*Ramp/(Ramp-10), where Ramp is the in impedance of the amp. What value should I use (I think I might asked that some time ago, but just to be sure)?
Yes, they have the HD 6XX for $199.99. This one HD 58x has the 660S's 150Ω driver but they added open cell foam pad behind the mesh and thin paper at the driver's basket opening for some more bass and a tad less treble. You can feel the exterior sounds getting quieter somehow like 3dB down vs fully open cans the moment you wear them on.
I listened to them vs the HD 600 on the DCG3 and on the smartphone. They are two clicks more sensitive on my 24 positions switcher volume pot than the 600 because of lower (half) impedance thus helping for louder volume on the smartphone too. Battery powered mass consumer devices are better in delivering more current than more voltage due to working from a low rail as we all know.
They are less wide than the 600 but more focused and smoother with more satisfying bass. Their stage is more contained but more coherent. My speakers showed that the balance of the 600 is more neutral above midbass but the 58x is nearer to correct in fullness from midbass and below. Fleshing out voices and guitars, delivering some bass thump. The speakers tonally draw a line exactly between them phones across the spectrum. The 600 is nearer in level and detail to the speakers HF but not as silky. The 58x midbass is bit more blown than from the speakers, its HF more reticent in level. Clarity is very good in both models. Stage and projection is different when comparing speakers to any cans of course, the speakers are more persuasive because in actual room space, but talking mainly balance now.
On my musically thinner bodied smartphone output the HD 58x locked a good overall synergy and it was driven to a point that it could be called loud enough, but clearly below solo partying levels, where with the 300Ω HD 600 cans the smartphone (OnePlus X) was just enough to lets call "conservative tastes" in drive and max volume for casual listening.
I listened to them vs the HD 600 on the DCG3 and on the smartphone. They are two clicks more sensitive on my 24 positions switcher volume pot than the 600 because of lower (half) impedance thus helping for louder volume on the smartphone too. Battery powered mass consumer devices are better in delivering more current than more voltage due to working from a low rail as we all know.
They are less wide than the 600 but more focused and smoother with more satisfying bass. Their stage is more contained but more coherent. My speakers showed that the balance of the 600 is more neutral above midbass but the 58x is nearer to correct in fullness from midbass and below. Fleshing out voices and guitars, delivering some bass thump. The speakers tonally draw a line exactly between them phones across the spectrum. The 600 is nearer in level and detail to the speakers HF but not as silky. The 58x midbass is bit more blown than from the speakers, its HF more reticent in level. Clarity is very good in both models. Stage and projection is different when comparing speakers to any cans of course, the speakers are more persuasive because in actual room space, but talking mainly balance now.
On my musically thinner bodied smartphone output the HD 58x locked a good overall synergy and it was driven to a point that it could be called loud enough, but clearly below solo partying levels, where with the 300Ω HD 600 cans the smartphone (OnePlus X) was just enough to lets call "conservative tastes" in drive and max volume for casual listening.
Salas DCG3 preamp (line & headphone)
Thank you for such a detailed review! I am debating which one to get. ATH-50 are in my list as well as I am listening music at work and really afraid SH will be too loud for other people even nobody seats next to me.
Thank you for such a detailed review! I am debating which one to get. ATH-50 are in my list as well as I am listening music at work and really afraid SH will be too loud for other people even nobody seats next to me.
I managed to get a pair of dual secondary trafos for this project. They measure 25.8v unloaded. They were billed as 19v. Will the drop under load make them suitable?
They should come down around nominal when loaded. You could pre-test that if you would load each secondary with a 100 Ohm 10W power resistor and measure their AC output again.
Building my third preamp, thank you Salas for such a great design 🙂. This time I will be using UBIB in dual mono configuration in PSU. What would be the best value for the limiter R1 if I am planing to bias DCG3 @ around 150mA? Thanks!
You could use 1.8R to 2.0R for 270 to 300 mA consumption on the UBIB (depending on the mosfets)