Hey everyone,
So I have my new turntable (Pro-Ject Debut Pro) with an iFi Zen phono preamp. Currently, I have no preamp with volume control.
I’m thinking of purchasing a Schiit Saga S preamp and hooking it up as follows to my two ACA in mono bridged configuration.
Turntable Out >> iFi Zen Phono In
iFi Zen Phono Out >> Schiit Saga S In
Schiit Saga S Out(s) Pass ACAs in
Should this work?
So I have my new turntable (Pro-Ject Debut Pro) with an iFi Zen phono preamp. Currently, I have no preamp with volume control.
I’m thinking of purchasing a Schiit Saga S preamp and hooking it up as follows to my two ACA in mono bridged configuration.
Turntable Out >> iFi Zen Phono In
iFi Zen Phono Out >> Schiit Saga S In
Schiit Saga S Out(s) Pass ACAs in
Should this work?
Not sure it warrents a new thread but I have an odd problem. My pair of ACAs had been running fine in parrallel mode for over a year but recently a fault developed where the volume from one of the amps reduced by about 30 percent. It is quite random when the problem strikes, maybe a few minutes after powering on, maybe a few hours and yesterday full volume on the offending amp came back by itself!!. Sometimes I can reset by powering on and off, sometimes not. All 4 heatsinks are as hot as each other and a quick look inside the case shows no obvious signs of loose connections or anything blown. interestingly as well I cannot repeat the problem in balanced, bridged or plain stereo mode. I am baffled.
Most likely something simple is happening. If one of the parallel pair loses its input signal the other will be working into effectively a low impedance (the non working channel) and that will dramatically cut the level. It may sound distorted as well.
Could be something like the switch on the back that is used to select modes playing up with a high resistance contact.
Could be something like the switch on the back that is used to select modes playing up with a high resistance contact.
Any budget amplifier that you would recommend for decent performance ? I have the same speakers and based out of India.Last weekend took the amp to native and play it with sony ss-rv900 speakers (3 way speaker) from Sony Hi-fi setup. Though the hi-fi setup was rated at 150w+150w, got decent (but not much loud, may be little louder would have been better) sound from ACA played with mobile as input source. But when played it from a laptop (vnc player) got nice loud volume from the ACA amp driving the these speakers ....
5w amp looked very nice loud with speakers rated at 150w each..
Now may be need to get a nice preamp for the ACA amp with gain, as with laptop as source ( seems which has good gain compared with mobile phone) sounded loud enough and some updates to handle the excess heat that my amp is generated with my given heat sink..
Hi, I have a question. What does the 2R2 ohm bypass resistor do (does it limit the HF impedance to ~2 ohms total) and is it necessary in a CLC intended as part of an outboard linear PSU for Class A amplifiers?
This is from the rebuild I did on my M2x.
https://www.diyaudio.com/community/threads/the-diyaudio-first-watt-m2x.321925/post-6954668
The Hammond 154B chokes would work well for an ACA power supply. Adding a 2.2 Ohm resistor in parallel with the choke reduces the Q factor.
https://www.diyaudio.com/community/threads/the-diyaudio-first-watt-m2x.321925/post-6954668
The Hammond 154B chokes would work well for an ACA power supply. Adding a 2.2 Ohm resistor in parallel with the choke reduces the Q factor.
ACA dual balanced monoblock pair power supply build, using the DIY Universal Power Supply PCB question.
I appreciate your patience and insight.
Q1: IFF Pwr Supply has updated 24 DC design change from the original ACA 19 DC build, the older 2005 version. THEN should the 18v transformer be upgraded also to a 24v transformer?
Q2: Which 'toroidal audio power transformers, offered by AnTek (or other) should I safely purchase?
Q3: Finally, what bridge block makes the most sense to purchase?
John Reel
I appreciate your patience and insight.
Q1: IFF Pwr Supply has updated 24 DC design change from the original ACA 19 DC build, the older 2005 version. THEN should the 18v transformer be upgraded also to a 24v transformer?
Q2: Which 'toroidal audio power transformers, offered by AnTek (or other) should I safely purchase?
Q3: Finally, what bridge block makes the most sense to purchase?
John Reel
Q1 - As a reasonable rule of thumb with a CRC using the UPS V3, you can use a 18VAC transformer to provide 24VDC output.
Q2 - Dual mono or one transformer for a stereo amp? See this thread for some ideas. https://www.diyaudio.com/community/threads/aca-amp-with-premium-parts.328357/page-68#post-7346800
Edited Q2 - you stated dual balanced monoblock. Antek's AS2218 might be a nice place to start.
Q3 - So many options. Others with a true preference and their reasoning can offer some help there. I like these... FWIW. https://www.mouser.com/ProductDetail/onsemi-Fairchild/GBPC3502?qs=j%2BucPx4PkG66Qy0UInQzXQ==
Q2 - Dual mono or one transformer for a stereo amp? See this thread for some ideas. https://www.diyaudio.com/community/threads/aca-amp-with-premium-parts.328357/page-68#post-7346800
Edited Q2 - you stated dual balanced monoblock. Antek's AS2218 might be a nice place to start.
Q3 - So many options. Others with a true preference and their reasoning can offer some help there. I like these... FWIW. https://www.mouser.com/ProductDetail/onsemi-Fairchild/GBPC3502?qs=j%2BucPx4PkG66Qy0UInQzXQ==
^
To expand on that, the ACA will try and maintain output despite the lower value coupling cap. In practice this means that the output level before the cap increase as frequency falls, the result is that the amp clips way before it should at lower frequency.
This shows the output into 8 ohms with a 100uF cap before and after the cap. The solid green trace shows that output is maintained down to 10 Hz but look how much more output is needed (solid red trace) to achieve that. The result is clipping as frequency falls.
To expand on that, the ACA will try and maintain output despite the lower value coupling cap. In practice this means that the output level before the cap increase as frequency falls, the result is that the amp clips way before it should at lower frequency.
This shows the output into 8 ohms with a 100uF cap before and after the cap. The solid green trace shows that output is maintained down to 10 Hz but look how much more output is needed (solid red trace) to achieve that. The result is clipping as frequency falls.
