You are probably using auto correction software that made me a Latin music genre
The current is either 100mA or 150mA bias plus a little more for the driver stage, the relay, and the servo chip. It draws 20W from the wall at 100mA bias stereo with its usual DCSTB supplies. If +/-18V is available you are at the servo chip's max spec so better use a +/-24V rails capable chip like the OPA2604. 16V won't do any harm, it might just sound a bit sweeter than neutral. But the tonal details can be also affected by other build choices like volume pot type etc. In general remember to roughly have +/- 0.5A capability when trying various other discrete supplies or chip supplies. Bandwidth is near 1MHz with 20K log pot at its midpoint worst case output impedance.
Me too. DCG3 is primarily meant to be a line level preamp. But some use it exclusively as an HPA.
Layout copied off of bambadoo's project as seen here:
http://www.diyaudio.com/forums/anal...g3-preamp-line-headphone-172.html#post5037088
Here's mine so far, still need extender sets and heat sink.
http://www.diyaudio.com/forums/anal...g3-preamp-line-headphone-172.html#post5037088
Here's mine so far, still need extender sets and heat sink.
Attachments
![IMG_4670[1].JPG](/community/data/attachments/608/608545-0be27a02a4ad37b9cf0a3ae37aa9e28b.jpg)
![IMG_4671[1].JPG](/community/data/attachments/608/608547-384c44be93a302b8d7b8529840dc5515.jpg)
DCG3 not enough bass
Hello, after successfully building a mesmerized B1 buffer and enjoying great sound through my F5 turbo amp I decided to build a DCG3. I got a full kit with dual mono power supplies from Tea Bag. I set it up as a single input preamp in an old velodyne chassis. I am using a ladder type 20 KOhms pot as volume control.
Lately I noticed a lack of bass, there is bass but my full range NHT 2.9's with 10" woofers sound like a mini monitor, you can hear some bass clean and well defined but lacking strength. I wired the input to the pot and from the pot to the amp board using CAT 6 wires, a pair of twisted conductors from the RCA's to the pot and then to the preamp board. I've check polarity of inputs, outputs all seem good. Any ideas where the culprit could be? Thanks
Hello, after successfully building a mesmerized B1 buffer and enjoying great sound through my F5 turbo amp I decided to build a DCG3. I got a full kit with dual mono power supplies from Tea Bag. I set it up as a single input preamp in an old velodyne chassis. I am using a ladder type 20 KOhms pot as volume control.
Lately I noticed a lack of bass, there is bass but my full range NHT 2.9's with 10" woofers sound like a mini monitor, you can hear some bass clean and well defined but lacking strength. I wired the input to the pot and from the pot to the amp board using CAT 6 wires, a pair of twisted conductors from the RCA's to the pot and then to the preamp board. I've check polarity of inputs, outputs all seem good. Any ideas where the culprit could be? Thanks
Attachments
I have almost the same setup as yours, beside speakers brand. Same F5T set to about 57W monoblocks, DCG3 x3 gain and 6R nominal impedance on Acoustic Zen Adagios. Speakers are known for weak low bass, but with these components I achieved perfect synergy and bass is very natural. I couldn’t get close to that low frequency and general clarity presentation with my Tube gear. It it very well sounds for my taste.
It sounds like you made some mistake somewhere and need to find it. It should be plenty of bass, particularly with 10” dedicated driver. I also used B1 with great success and this is how I decided to go with x3 gain calculated without F5T clipping. Make drawing and let’s see how you connected your pot and outputs. I just guessing at that point and Salas might get to the the root-cause immediately.
It sounds like you made some mistake somewhere and need to find it. It should be plenty of bass, particularly with 10” dedicated driver. I also used B1 with great success and this is how I decided to go with x3 gain calculated without F5T clipping. Make drawing and let’s see how you connected your pot and outputs. I just guessing at that point and Salas might get to the the root-cause immediately.
Thank you Alexkosha. This set up in very musical. The DCG3 has better resolution than the DCB1 but b the weak bass makes the sound a bit bright. I'm using 7.5 ohms resistors to set the bias of the output devices.
I'm suspecting the stepped ladder type attenuator, the quality is unknown, I got it from a fellow member who sold me the kit for the turbo and the DCB1.
I'm suspecting the stepped ladder type attenuator, the quality is unknown, I got it from a fellow member who sold me the kit for the turbo and the DCB1.
I would start with basic tests. Can you check your current setting by measuring voltage drop on that bias set 7.5R resistor? I’m running bit high - 165mA, but I have very good heat dissipation since I use 20mm x 50mm x 400mm copper bar attached to the enclosure bottom with thermal compound. What is you PSU voltage +/0/- on both channels?
I use low capacitance microphone Mogami 2330 coax (bare copper) advised by forum guys to use on phonos. Potentiometers or step attenuators are very important and I use the best quality that I can effort $.
All kits from Tea bag contain 221R vs 150R in schematic. It matches better to his batch of JFETs. I use it too.
@ Keremito
Bass slam is one of the highlights when using a DCG3. Lack of bass isn't normal. I would suspect either some bad contacts in the signal path or some wrong resistor value around the servo (R12,13,14) or at the output (R15) or some oscillation on the rails or an out of range output impedance volume pot than suitable. Also measure the voltages at Q1 Q2 collectors and at J3's (Q5) drain against ground and let us know.
Bass slam is one of the highlights when using a DCG3. Lack of bass isn't normal. I would suspect either some bad contacts in the signal path or some wrong resistor value around the servo (R12,13,14) or at the output (R15) or some oscillation on the rails or an out of range output impedance volume pot than suitable. Also measure the voltages at Q1 Q2 collectors and at J3's (Q5) drain against ground and let us know.