February 26, 20179 yr Awesome build! What chassis, and where do u get the power button from ? Is there any real advantage to go with Separated PSU box ? I am planing to build with Dissipante, but mini-dissipante may works better ?
February 27, 20179 yr Chassis are semi-customized and buttons are also from the manufacturer. Separated PSU theoretically would prevent 60HZ AC noise. The reason I use separated box was much simpler.... Because it's hard to fit GG in one box or it would be HUGE. Since customized chassis has MOQ, I want carbon, GG, BH to share a same design to lower the cost of customized chassis. I had to order a batch of those. So yeah, more amps coming. Edited May 2, 20179 yr by joehpj
February 27, 20179 yr Love the modular concept that leverages the PS across several amplification platforms. Smart and efficient IMO. HS
February 27, 20179 yr 18 hours ago, Whitigir said: Awesome build! What chassis, and where do u get the power button from ? Is there any real advantage to go with Separated PSU box ? I am planing to build with Dissipante, but mini-dissipante may works better ? It looks like a Bulgin Vandal resistant switch, something like this http://www.bulgin.com/products/switches/push-button/stainless-steel-push-button-mp0045-1d0-mp0045-3d0-mp0045-1e0-mp0045-3e0-series-18mm-diameter-group.html (possibly the illuminated version). Mouser has a bunch of different versions..
February 28, 20179 yr Hello, i have a noob question and I need some helps please. I am seeing 1M resistor on the Boards, and there is no resistor of this value on the BOM in the first post ? Also, can someone please confirm to me that the middle resistor of 1.5k here is to be 750 ohm instead ? Thanks
February 28, 20179 yr the pair of 1.5k resistors and the 10 volt reference make a 20V output voltage the pair of 1M resistors and the 100k pot are for trimming the output voltage and are optional not sure where the 750 ohm came from
February 28, 20179 yr That is awesome, so I can directly connecting the Pot without the miniboard ! Thanks for confirming
February 28, 20179 yr Just now, Whitigir said: That is awesome, so I can directly connecting the Pot without the miniboard ! Thanks for confirming might be stretching it a bit ... the two 1Meg + trim is really only needed if you care about mV accuracy ...you can omit those
February 28, 20179 yr for 15V, have to recalculate the values of the 1M resistors. So one of them would need to be 473k Edited February 28, 20179 yr by kevin gilmore
March 3, 20179 yr My GRHV has 511-STN9360 On the back so it will need 2x. While the BOM list doesn't have it yet. The whole things need 6x as 2x are on each channel board
March 8, 20179 yr I have another noob question .... how do we de-energize the bias properly ? Do we drain it at the "bias TP" similar to draining a capacitor ?
March 8, 20179 yr On 04/03/2017 at 2:28 AM, Whitigir said: My GRHV has 511-STN9360 On the back so it will need 2x. While the BOM list doesn't have it yet. The whole things need 6x as 2x are on each channel board The opening post lists it in the BOM. It also lists it in the Mouser project cart.
March 8, 20179 yr Hm, low voltage is working. However the amp board has very weak LED and test point doesn't measure to anything. Anyone has any idea ?
March 8, 20179 yr 2 hours ago, Whitigir said: Hm, low voltage is working. However the amp board has very weak LED and test point doesn't measure to anything. Anyone has any idea ? You need all the voltages to work before doing any further trouble shooting
March 8, 20179 yr I thought I only need Low voltage to be able to adjust the current, offset, and balances trims ?
March 8, 20179 yr Great! Thank you for the confirmations ! It is horrible to be lacking only 1 thermal alloy and it washer to complete the HV lol!
March 9, 20179 yr 12 hours ago, Whitigir said: I thought I only need Low voltage to be able to adjust the current, offset, and balances trims ? You can trim the CSS's using only LV and a DMM in mA mode (assuming AMP board is not connected to anything): Connect LV+ -> AMP HV+ Connect LV- -> DMM (Common) Connect DMM.(+) -> the probe put the probe to the tail of the CSS (the Drain of the Sics (middle leg)) Now you'll have the CSS current reading directly on the meter, and the CSS can be trimmed to what ever current < 27mA you have sinks for (one might shoot a mA lower as the current grows a bit at higher voltage and heat). Trimming the output stage tail resistor to get the amp in balance and DC balance requires all voltages
March 9, 20179 yr 13 hours ago, Whitigir said: I thought I only need Low voltage to be able to adjust the current, offset, and balances trims ? umm, you might want to rethink doing this...
March 9, 20179 yr The cascode current source can be set with an LV source. Connect positive voltage to B+ terminal of the amp board. Connect negative voltage to the end of the 100ohm resistor adjacent to the DN2540 away from the heatsink. Measure voltage between the testpoints. Adjust until measurement is 1V for 20mA. (Calculation is 50ohms / 0.02A = 1V).
March 9, 20179 yr Thank you so much to 4 hours ago, insanity said: The cascode current source can be set with an LV source. Connect positive voltage to B+ terminal of the amp board. Connect negative voltage to the end of the 100ohm resistor adjacent to the DN2540 away from the heatsink. Measure voltage between the testpoints. Adjust until measurement is 1V for 20mA. (Calculation is 50ohms / 0.02A = 1V). I have successfully adjusted the current using your method. I have made out a picture here for future people needs https://imageshack.com/i/plNJXzaHj
March 14, 20179 yr So I fired it up, everything works, but one of my amp board is not working as only 1 led is on, the second led on the HV is not on :(. Anyone has any clues ? I think I smell something and...50k resistor is burned out
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