38 replies to this topic

[SvenMZ8]

im assuming HO means "headphone out"? u need to be more clear.
it still works.
i have the blackgates, pm if u want them.

[SvenMZ8]

Balanced Amp completed

-Converts unbalanced signal to balanced
-9V rechargable battery with charging circuit
-Black and white Faceplate






Balanced Audio Technica FC-700 to go with the new amp



With imod + sonicaps

[domm123]

Hi, can i know where you get your 3.5mm socket from? and do you know any places in singapore that sells chloroform?



Thanks

Edited by domm123, 10 October 2010 - 04:15 PM.

[SvenMZ8]

changes to tube amp. simple yaha on 15v

[jmwreck]

great tubes, hope you can make O2

Edited by jmwreck, 24 August 2011 - 12:24 AM.

[d4rkm4st3r]

Amazing work..

Btw, I tried using a no cap LOD on my diymod but nothing really happen..

I connected it to a cmoy amp.. Izzit bcos the caps in the cmoy blocked the voltage?

[p e t e r..]

Hi~ May i know what is ur setup on Soniccap? how to connect 4.7uF and 0.1uF?

whether is just join 2 together end to end?

4.7uF positive + 0.1uf positive & 4.7uF negative + 0.1uF negative?

Edited by p e t e r.., 24 October 2011 - 10:58 AM.

[SvenMZ8]

@d4rkm4st3r

yes

[SvenMZ8]

Designed another amplifier after taking apart my Pimeta amplifier. This time its a Pimeta without the use of virtual ground, thus its a two channel amplifier. A real dual supply, + and - voltages and a true ground is used.
The merits of using such a design is covered here by NwAvGuy
http://nwavguy.blogspot.sg/2011/05/virtual...annel-amps.html

The negative voltage supply is generated by a charge pump TPS60403, which is a voltage inverter. The power supply is a 3.7V PSP Lithium ion battery, thus with the charge pump, the voltages supplied is +3.7V and -3.6V.

To ensure that the performance of the charge pump is not affected by PCB layout, the recommended layout in the datasheet is followed closely.




As you can see, the charge pump sits very closely with the ceramic capacitors to reduce parasitic inductance.
The audio amplifier section is also similarly made compact to reduce the footprint and size of the amplifier.





As the charge pump switching frequency is 250KHz, which is within the bandwidth of most opamps. Thus the chosen audio opamp requires a high PSRR to reject power supply noise generated by the charge pump. The chosen LTC6241HV has a minimum PSRR of 83dB when supplied with +-5V.

The input and outputs of the amp is placed above the circuitry to reduce the footprint. The entire amp, including the PSP battery fits inside a hammond 1455C801 aluminium casing.






Components
Power Supply Section
Battery: 3.7V Lithium ion battery
Charge pump: TPS60403
Ceramic Capacitors: 1uF X5R 0603
Voltage Rail Capacitors: 220uF/4V Blackgates PK Series
Bypass Capacitors: WIMA 0.1uF/63V

Audio Amplifier Section
Audio Opamp: LTC6241HV, Gain set at 2.
Buffers: BUF634U
Volume control: Alps Potentiometer 50K LOG

Edited by SvenMZ8, 28 January 2013 - 11:02 AM.