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View Full Version : Beresford TC-7530DC Bushmaster MKI Venom-3 mod.



StanleyB
21-03-2014, 08:43
Here is a reasonably simple mod for the Bushmaster MKI (TC-7530DC) that anyone with basic soldering skills should be able to manage. This mod improve the overall sound quality by quite a big margin, especially if you are using a linear PSU, sBooster, or batteries.
Sound wise it surpasses the Venom1 and 2 mods. Improvements to expect are:
Less glare, more detailed depth, better frequency response across the range.


This mod does not require the removal of the PCB from the case. All changes can be carried out with just the top cover of the Bushmaster removed.

http://www.homehifi.co.uk/images/mods/7530/7530%20op%20org.jpg

The standard output from the DAC chip has a filter network made up of R28/R29 and MLC20/MLC21 as shown above.

To carry out the mod, you need to do the following.

Replace surface mount resistors R28 and R29 with a couple of metal film or equivalent low noise resistors of 1/8 or 1/4 Watt, 120 Ohms. Cut the excess part of the legs on the resistors and solder them onto the PCB as shown. Make sure that you add enough solder so that the resistors don't come off.

Next, replace MLC20 and MLC21 with a 15nF WIMA cap with a leg spacing of 2.54mm. If you use one of these, you won't have to bend any legs on the caps.

http://www.homehifi.co.uk/images/mods/7530/V3.jpg


The mod improves the headphone output clarity as well. But an additional headphone mod will be posted to go with it.
A matching Firmware upgrade based on the code from the BMII has been ported over and made compatible with the BM MKI. Together with the above mod the TC-7530DC can be brought close to the BMII with the latest FW.
Anyone interested in the modded BMI firmware should email me for the price.

synsei
21-03-2014, 14:03
Here is a reasonably simple mod for the Bushmaster MKI (TC-7530DC) that anyone with basic soldering skills should be able to manage. This mod improve the overall sound quality by quite a big margin, especially if you are using a linear PSU, sBooster, or batteries.
Sound wise it surpasses the Venom1 and 2 mods. Improvements to expect are:
Less glare, more detailed depth, better frequency response across the range.


This mod does not require the removal of the PCB from the case. All changes can be carried out with just the top cover of the Bushmaster removed.

http://www.homehifi.co.uk/images/mods/7530/7530%20op%20org.jpg

The standard output from the DAC chip has a filter network made up of R28/R29 and MLC2/MLC21 as shown above.

To carry out the mod, you need to do the following.

Replace surface mount resistors R28 and R29 with a couple of metal film or equivalent low noise resistors of 1/8 or 1/4 Watt, 120 Ohms. Cut the excess part of the legs on the resistors and solder them onto the PCB as shown. Make sure that you add enough solder so that the resistors don't come off.

Next, replace MLC21 and MLC22 with a 15nF WIMA cap with a leg spacing of 2.54mm. If you use one of these, you won't have to bend any legs on the caps.

http://www.homehifi.co.uk/images/mods/7530/V3.jpg


The mod improves the headphone output clarity as well. But an additional headphone mod will be posted to go with it.
A matching Firmware upgrade based on the code from the BMII has been ported over and made compatible with the BM MKI. Together with the above mod the TC-7530DC can be brought close to the BMII with the latest FW.
Anyone interested in the modded BMI firmware should email me for the price.

Shouldn't this be MLC20/21 Stan? Let me know if it needs correcting so I can edit your post accordingly ;)

StanleyB
21-03-2014, 14:13
Yes please edit that for me. I only have one perfect eye to read with right now..

synsei
21-03-2014, 14:16
Yes please edit that for me. I only have one perfect eye to read with right now..

No worries, all done ;)

isj1202
05-04-2014, 11:37
Could anyone give me a link or an actual part number for the wima caps

Farnell do not list any with a lead spacing of 2.5mm, smallest is 10mm.

Thanks Iain

istari_knight
05-04-2014, 13:02
Could anyone give me a link or an actual part number for the wima caps

Farnell do not list any with a lead spacing of 2.5mm, smallest is 10mm.

Thanks Iain

I think Rapid sell them.

isj1202
06-04-2014, 11:41
Thanks, I assume it's these
http://www.rapidonline.com/Electronic-Components/15nf-63v-Mks2-Mini-Poly-Capacitor-Case-A-10-2206
package type 1A

or these
http://www.rapidonline.com/Electronic-Components/15nf-63v-Mks02-Mini-Polyester-Capacitor-10-1067
package 0B

Ordered both as only a few pence.

Iain

StanleyB
06-04-2014, 17:41
Could anyone give me a link or an actual part number for the wima caps

Farnell do not list any with a lead spacing of 2.5mm, smallest is 10mm.


farnell = http://uk.farnell.com/jsp/search/productdetail.jsp?sku=1005999
Read the specs. Ignore the picture. That is the wrong thing shown.

isj1202
08-04-2014, 10:26
Thanks Stan

When done will get in touch about the firmware update, probably x2 to save on postage and hassle

Iain

StanleyB
08-04-2014, 10:35
No problem :).
From emails that I have received so far the V3 and V4 mods are hitting the right spot.

nat8808
08-04-2014, 12:43
Out of interest, what would happen if the SMD caps were bypassed (leaving the originals in)? Would the sound be different yet again and is complete removal the best idea?

StanleyB
08-04-2014, 12:59
You have to remove the caps. The old and new caps are made out of different materials, with differing sound qualities and parameters.

istari_knight
10-04-2014, 21:08
Now done. (http://theartofsound.net/forum/showthread.php?29934-The-system&p=541185#post541185) A very worthwhile improvement :thumbsup: