I elivated this amp to a whole new level, by adding a new preamp - the Zen Mod Iron Pre. Listening to all my music all over again. So darn musical, insane fine details not heard before. Never heard such tight and clear bass before. Jawdropping improvement.
The Iron Pre replaced a Pass H2 preamp. Before that I tried a B1.
Maybe it's transformer magic? The Iron Pre has transformer outputs, and the TDA8932 amp has transformer inputs.
All I know is - they work so well together I can live with this setup for the rest of my life. Beautiful match. 🏆
The Iron Pre replaced a Pass H2 preamp. Before that I tried a B1.
Maybe it's transformer magic? The Iron Pre has transformer outputs, and the TDA8932 amp has transformer inputs.
All I know is - they work so well together I can live with this setup for the rest of my life. Beautiful match. 🏆
Nice report.!
I always use a preamp and mine is a Salas DCG3. Indeed it pairs very nicely with Richards amps.
I've been reading about the M2X and it too has an input trafo as voltage gain. 600:15k so a 1.5 step up. They have swappable input boards. No idea if they're compatible but it gets me thinking!
I always use a preamp and mine is a Salas DCG3. Indeed it pairs very nicely with Richards amps.
I've been reading about the M2X and it too has an input trafo as voltage gain. 600:15k so a 1.5 step up. They have swappable input boards. No idea if they're compatible but it gets me thinking!
Always interested when an amp's using a trafo.... I looked up the M2X and its using an Edcor steel trafo. Might be interesting to try a permalloy one in that role, like these : https://www.aliexpress.com/item/32810469047.html. The ferrite trafo on monoamp is step down by a not-too-far-off ratio, I doubt it could be turned around to use as step-up because its windings aren't interleaved so leakage inductance would likely be a problem.
Wishing you many hours of delighted listening @twocents!
Wishing you many hours of delighted listening @twocents!
I wondered if any of the M2X first stages would be worth a try on monoamp, to provide a nice low impedance input. They are basically a unity gain buffer. Many different designs/topologies. They don't have a ground though so I was lost after that!
Thank you Richard. The next (maybe final) upgrade to my system will be the DAC. Eyeing the Abbado for a while now.
Any issues using the amp with 4ohm speakers at low power levels? I've realized the two sets of speakers I've been using lately are all 4ohm. I could pull out some of my other ones, or build something new, but curious what negative effects it would have on sound quality/performance.
At low power levels the TDA8932s aren't going to overheat and the on-board regulators aren't going to over-current so the only issue of note would be the high frequency response is going to be a bit more curtailed with 4R than 8R.
I'm curious, would this amp play nicely with a USB-C PD power source stepped up using one of these Wondom boost converter boards? TBH, still a DIY audio newbie, so still figuring things out! Just thought with the ubiquity of USB-C PD now, is there a way to clean up the power from a USB-C PS that many folks have, especially for low power amps like this one.
I can't see why that wouldn't work - certainly if the 100W power output is real it should have a current limit about 4A with 24V output, which is plenty for a single monoAMP. A pair would play nicely so long as the volume wasn't pushed to the limit.
An LC filter is what I use when I need to clean up a switching PSU's output. I happen to have PCBs for it too -
An LC filter is what I use when I need to clean up a switching PSU's output. I happen to have PCBs for it too -
Oh very nice! If I'm understanding these boards correctly, it looks like one PSU filter can work with two independent inputs and outputs?
Also, are you selling these as a kit or fully assembled as well? I would be interested in purchasing a pair.
The filters we sell fully assembled. Send me a PM if you're interested in buying. You're correct, one filter board contains two independent filters.
New member here, wanted to place an order but i can't send personal messages yet. So please pm me.
Just wanted to show off a little...mounted the amps in a small case, with a tiny Smps and a filter from Diyaudio store.
I still like them a lot, as they don't sound like a typical class d.
I still like them a lot, as they don't sound like a typical class d.
Hi Richard, wifey and all Abrax users!
Can we parallel the mono amps to help with current delivery for lower impedance loads.?
Can we parallel the mono amps to help with current delivery for lower impedance loads.?
You can do it (I've tried it) but you will need to check that the gain of the paralleled channels are similar enough to make it worthwhile. I measured - DVM on AC range - to check that there was better than 0.5% matching of gain and then used 0.5R on the output and a largeish 'lytic as the DC offset can be significant.
Is NXP TDA8932B available for purchase? I'm interested in 4 Pieces
Or is equivalent available from NA suppliers?
Or is equivalent available from NA suppliers?
A few AliX sellers are offering TDA8932, for example : https://www.aliexpress.us/item/33020893099.html
I have 2 mono amps(r3) running. Well, they were running. I tested them after the assembly, then after install in chassis. everything looked good. Red light extinguishes, good on the scope. good with a dummy load at 25w dissipation. Connected to speakers and ran music for 2 hours.
The next day red lights on both wont go out..
Looking at schematic I can do a bit of trouble shooting but not certain what to expect at different test points..
at this point, no input signal and no load is connected. red light stays on.. PSU is 24V linear regulated..
thinking maybe TDA but just a guess..
The next day red lights on both wont go out..
Looking at schematic I can do a bit of trouble shooting but not certain what to expect at different test points..
at this point, no input signal and no load is connected. red light stays on.. PSU is 24V linear regulated..
thinking maybe TDA but just a guess..
I think the key node to check would be the output of the LM317 regulator (pin2, the middle one) that supplies the signal rail to TDA8932. The LM317 is the regulator that doesn't have a heatsink.