Hi,
Just like to share some info on the switching I recently built. Unlike most others, this one is based on Tripath's bridged TA3020 reference board. We had someone manufactured the PCBs and assembled them ourselves. Internal wires will be trimmed when everything is finalized.
The sound so far is above my original expectations so more parts upgrade and circuit revisions will come.
Here are some facts:
Chip: Tripath TA3020
PCB design: Tripath bridged TA3020-2
Arrangement: Dual mono PCB but shared PS (limited room)
Main toro: Plitron 1500VA (30 lbs)
Main filter caps: 2 10,000uF/75V Mallory per rail
Power FET: 8 STW34N20 (34A N-FET) per channel
Power: >500W/ch
Idle power: 25W to >140W depends on setting
Net weight: 43 lbs
Hope to hear from people who have built Tripath amps. Other comments welcome too.
Cheers.
Ehien
Just like to share some info on the switching I recently built. Unlike most others, this one is based on Tripath's bridged TA3020 reference board. We had someone manufactured the PCBs and assembled them ourselves. Internal wires will be trimmed when everything is finalized.
The sound so far is above my original expectations so more parts upgrade and circuit revisions will come.
Here are some facts:
Chip: Tripath TA3020
PCB design: Tripath bridged TA3020-2
Arrangement: Dual mono PCB but shared PS (limited room)
Main toro: Plitron 1500VA (30 lbs)
Main filter caps: 2 10,000uF/75V Mallory per rail
Power FET: 8 STW34N20 (34A N-FET) per channel
Power: >500W/ch
Idle power: 25W to >140W depends on setting
Net weight: 43 lbs
Hope to hear from people who have built Tripath amps. Other comments welcome too.
Cheers.
Ehien
Attachments
Hello!
I just want to congratulate you on this great looking amp. I especialy like the golden front plate. I have just ordered one for my Aleph 5. How much did it cost you(the front plate)?
How old is TA3020? I haven't heard for it yet. Majbe it's just me, but I would realy like to see the schematic. Can you help?
How much did the whole amp cost?
Regards,
DJG
I just want to congratulate you on this great looking amp. I especialy like the golden front plate. I have just ordered one for my Aleph 5. How much did it cost you(the front plate)?
How old is TA3020? I haven't heard for it yet. Majbe it's just me, but I would realy like to see the schematic. Can you help?
How much did the whole amp cost?
Regards,
DJG
As far as I know you can get them directly from Tripath.
Cadaudio (www.cadaudio.dk) in Denmark have some.
Carl
Cadaudio (www.cadaudio.dk) in Denmark have some.
Carl
To answer a few questions here:
1. Datasheets for TA3020 chip and the bridged (RB-TA3020) reference board can be found and downloaded at:
http://www.tripath.com/data.htm
2. The total cost was about $700. Just the 1500VA toro cost me $150 and the chassis about $110. I saved a lot by buildling the boards myself. Otherwise each bridged TA3020 board from Tripath is $450 and two are needed.
3. The nice looking chassis was purchased from:
http://www.thlaudio.com/indexE.htm
It's small for such an amp. But I got by with smaller Mallory caps (but high in quality) and boards attach to side panels/heatsinks.
4. I believe TA3020 chip is newer than TA0104 but may came out before TA0105. My friend and I have studied quite a bit and consulted with Tripath tech support before making the choice. It should sound no worse than TA0104/0105 and is easier to bridge and modify. Cheaper too ($12/ea). Now I see Bel Canto starts to use it in their 6-channel model. I'm betting to be eventually more popular and lives longer than current 0105.
5. The sound is very transparent and detailed. The main things I want to improve now is to regain the liquid mid and deeper soundstage I used to have with tubes. Otherwise I enjoy quite a bit with it. It does show superority of vinyls over CDs better than my C-J tube amp.
Cheers.
Ehien
1. Datasheets for TA3020 chip and the bridged (RB-TA3020) reference board can be found and downloaded at:
http://www.tripath.com/data.htm
2. The total cost was about $700. Just the 1500VA toro cost me $150 and the chassis about $110. I saved a lot by buildling the boards myself. Otherwise each bridged TA3020 board from Tripath is $450 and two are needed.
3. The nice looking chassis was purchased from:
http://www.thlaudio.com/indexE.htm
It's small for such an amp. But I got by with smaller Mallory caps (but high in quality) and boards attach to side panels/heatsinks.
4. I believe TA3020 chip is newer than TA0104 but may came out before TA0105. My friend and I have studied quite a bit and consulted with Tripath tech support before making the choice. It should sound no worse than TA0104/0105 and is easier to bridge and modify. Cheaper too ($12/ea). Now I see Bel Canto starts to use it in their 6-channel model. I'm betting to be eventually more popular and lives longer than current 0105.
5. The sound is very transparent and detailed. The main things I want to improve now is to regain the liquid mid and deeper soundstage I used to have with tubes. Otherwise I enjoy quite a bit with it. It does show superority of vinyls over CDs better than my C-J tube amp.
Cheers.
Ehien
Actually, there is another thing I'm trying to improve- high freq noise/hiss from speakers. It's not bad as I can barely hear it from listening chair in quietest background and most CDs/LPs have louder background noise than it. But I'd like to hear it even lower so one day higher efficiency (now 91dB) speakers can be used.
Because the noise didn't reduce much with input directly shorted on PCBs, I'm speculating most of them from chip itself or the output switching (+/-92V differentially).
Any advises?
Ehien
Because the noise didn't reduce much with input directly shorted on PCBs, I'm speculating most of them from chip itself or the output switching (+/-92V differentially).
Any advises?
Ehien
ehein, you may be already aware of this, but there is a thread over at Audio Asylum that discussed a hiss problem with DIY Tripath amps. You can follow the discussion here, it has to do wth grounding:
http://db.audioasylum.com/cgi/m.pl?forum=tweaks&n=37604&highlight=tripath&session=
http://db.audioasylum.com/cgi/m.pl?forum=tweaks&n=37604&highlight=tripath&session=
ehien, sorry! The thread starts here:
http://db.audioasylum.com/cgi/m.pl?forum=tweaks&n=37030&highlight=tripath&r=&session=
http://db.audioasylum.com/cgi/m.pl?forum=tweaks&n=37030&highlight=tripath&r=&session=
Hi Cherhit,
Thanks for the link. No, I was not aware of that particular thread on AA.
But I understood the issue on AGND, DGND, and +5V supply and had implemented it properly. The bridged TA3020 board was designed to tie AGND and DGND on board (not on chip) with a ferrite bead.
But one of the things I was thinking was reducing noises on +5V and AGND. Hmmm... maybe I should also check if the ferrite beads are damaged.
Anyway, thanks for the lead.
Ehien
Thanks for the link. No, I was not aware of that particular thread on AA.
But I understood the issue on AGND, DGND, and +5V supply and had implemented it properly. The bridged TA3020 board was designed to tie AGND and DGND on board (not on chip) with a ferrite bead.
But one of the things I was thinking was reducing noises on +5V and AGND. Hmmm... maybe I should also check if the ferrite beads are damaged.
Anyway, thanks for the lead.
Ehien
Hi!
One thing you should be aware of, that Tripath based amps cause a lot (and I mean REALLY a lot) of electromagnetical interferences. The would never really pass any industrial EMV (that's what those interferences are called in Germany) standards, which is why for example high-end DIY manufactuer THEL has dropped the development of a Tripath digital amp.
Maybe check it one time with a TV-set or radio receiver next to the amp...
But anyway, since it's DIY, who cares...
Ciao,
Arndt
One thing you should be aware of, that Tripath based amps cause a lot (and I mean REALLY a lot) of electromagnetical interferences. The would never really pass any industrial EMV (that's what those interferences are called in Germany) standards, which is why for example high-end DIY manufactuer THEL has dropped the development of a Tripath digital amp.
Maybe check it one time with a TV-set or radio receiver next to the amp...But anyway, since it's DIY, who cares...
Ciao,
Arndt
Ah... EMI/RFI...
I worried about it since early planning days as I knew this is the nature byproduct of these switching beasts. I even wanted to use a fully enclosed chassis with EMI/RFI gaskets. But they were too ugly...
I tried my FM tuner early on and it did drawn out even a local (3 miles away) station with whip antenna installed 10 ft above it. I then used FM feed from cable service and bypass this issue. The radiation should reduce a bit now as I later installed small (hundred pF) shunting caps at input/output per Tripath suggestions.
ehien
I worried about it since early planning days as I knew this is the nature byproduct of these switching beasts. I even wanted to use a fully enclosed chassis with EMI/RFI gaskets. But they were too ugly...
I tried my FM tuner early on and it did drawn out even a local (3 miles away) station with whip antenna installed 10 ft above it. I then used FM feed from cable service and bypass this issue. The radiation should reduce a bit now as I later installed small (hundred pF) shunting caps at input/output per Tripath suggestions.
ehien
Keep in mind that, for a noise-shaped device like a class-T amp, the SNR at the upper end will be lower than at low frequencies.
Furthermore (and this is true for ALL amps) for a given SNR, the noise emerging from a speaker with a given efficiency, is higher for higher powered amps !!!!
So if you don't ever need the headroom of a monster amp you are usually better off with a lower powered amp with the same SNR, because it gives you more FOOTROOM !!!!
Regards
Charles
Furthermore (and this is true for ALL amps) for a given SNR, the noise emerging from a speaker with a given efficiency, is higher for higher powered amps !!!!
So if you don't ever need the headroom of a monster amp you are usually better off with a lower powered amp with the same SNR, because it gives you more FOOTROOM !!!!
Regards
Charles
Hi Phase_accurate,
I agree with you completely. Also with a properly matched amp-speaker one can have wide "footroom" and "headroom".
With my 91dB speakers I likely need an amp half the power (or +/-33V instead of +/-46V rails). But I need to look forward in case my next speakers are less efficient.
Before the amp was built I just hope part of the noises to be cancelled out due to balanced bridged operation.
However, now I believe the HF noises are not cancelled, unless they are generated before inputs of the board. The noises from + and - outputs of a bridge board are not correlated because the switching is not synchronized.
The +/-92V differential switching is indeed larger than a non-bridged TA0104 (Bel Canto eVo2 or eVo200.2) at around +/-75V signle ended. But I still feel that somehow there are rooms to improve (on SNR).
Cheers.
ehien
I agree with you completely. Also with a properly matched amp-speaker one can have wide "footroom" and "headroom".
With my 91dB speakers I likely need an amp half the power (or +/-33V instead of +/-46V rails). But I need to look forward in case my next speakers are less efficient.
Before the amp was built I just hope part of the noises to be cancelled out due to balanced bridged operation.
However, now I believe the HF noises are not cancelled, unless they are generated before inputs of the board. The noises from + and - outputs of a bridge board are not correlated because the switching is not synchronized.
The +/-92V differential switching is indeed larger than a non-bridged TA0104 (Bel Canto eVo2 or eVo200.2) at around +/-75V signle ended. But I still feel that somehow there are rooms to improve (on SNR).
Cheers.
ehien
I built a four channel, bridgeable integrated amp based on TA0102A and +/- 45V rails. Power is 190WRMS x 4 into 4ohms at the threshold of clipping. The power supply was a custom designed and built switching power supply with an active PFC preregulator front end and a Zero-Voltage Switching converter stage. The power supply generated more EMI than does the amplifiers. The amplifers are spread-spectrum style so the switching energy is spead over a wider bandwidth and interferes less with the radio signals (especially if it is contained). There is some but the best test is the use of am AM radio. This will tell you really what is going on. These are good sounding amps if you ground correctly and keep switching loop areas small. Very, Very efficient. The units which I built reside in a 17"x3"x8" rack mount chassis and weighs less than 8 pounds. Power supply is good to about 1000W.
BeanZ
BeanZ
Sounds very cool. Much smaller and lighter than mine.
Do you notice more hum or noise when the amps is bridged (due to larger switching voltages)?
To be honest the current bridged arrangement in my amp is not perfect. I'd rather accept balanced inputs or use input transformers to convert single-ended inputs. But this will involve modification on part of the PCB.
I don't bother with AM. But last night I checked, now the amp added "white"noise to my local FM station instead of over powering it. I am still using the cable feed as it's shielded and quiet.
ehien
Do you notice more hum or noise when the amps is bridged (due to larger switching voltages)?
To be honest the current bridged arrangement in my amp is not perfect. I'd rather accept balanced inputs or use input transformers to convert single-ended inputs. But this will involve modification on part of the PCB.
I don't bother with AM. But last night I checked, now the amp added "white"noise to my local FM station instead of over powering it. I am still using the cable feed as it's shielded and quiet.
ehien
Noise
This is a long shot, but some time ago, an app note on the Tripath web page covered a 6-channel reference amp. As I recall, the app note discussed the adjustmetn of the feedback capacitor so that the no-load switching frequencies were at least 20kHz apart, to minimize noise due to the channels interfering. IIRC, they had noise spectra showing reduced noise due to this. When I last looked at there web site, a new app note was there, and did not discuss this issue.
I don't know if this is what is cuasing your noise, but perhaps it's worth looking into.
John
This is a long shot, but some time ago, an app note on the Tripath web page covered a 6-channel reference amp. As I recall, the app note discussed the adjustmetn of the feedback capacitor so that the no-load switching frequencies were at least 20kHz apart, to minimize noise due to the channels interfering. IIRC, they had noise spectra showing reduced noise due to this. When I last looked at there web site, a new app note was there, and did not discuss this issue.
I don't know if this is what is cuasing your noise, but perhaps it's worth looking into.
John
You are right that intermodulation of tones less than 20kHz apart could cause the noise I heard. But I never saw Tripath mentioning it and sort of dismissed the possibility.
Wonder if this issues is solved on later chips like TA3020 or on their reference board designs.
This is certainly something worth looking into.
OTOH, now if I think of it this way, the noise is not really an issue- my tube amp that's very quiet and having high SNR (close to 100dB A-weighted) has 1/10 the power rating of the switching amp, but more than 1/10 the noise.
But of course there is never too much improvements.
-ehien
Wonder if this issues is solved on later chips like TA3020 or on their reference board designs.
This is certainly something worth looking into.
OTOH, now if I think of it this way, the noise is not really an issue- my tube amp that's very quiet and having high SNR (close to 100dB A-weighted) has 1/10 the power rating of the switching amp, but more than 1/10 the noise.
But of course there is never too much improvements.
-ehien
TA-3020 Output MOSFETs
Tripath TA-3020 uses STW34NB20 output mosfets from SGS-Thomson
Have low Rds ON 0.06 ohms
but rather high Ciss
Input Capacitance: 2400pF
180W 34A Rthj-c 0.70C/W
STW34NB20 is called "PowerMESH(tm)" MOSFET
STW34NB20 Datasheet (8 pages)
Does anyone know more about these Transistors?
/halo
Tripath TA-3020 uses STW34NB20 output mosfets from SGS-Thomson
Have low Rds ON 0.06 ohms
but rather high Ciss
Input Capacitance: 2400pF
180W 34A Rthj-c 0.70C/W
STW34NB20 is called "PowerMESH(tm)" MOSFET
STW34NB20 Datasheet (8 pages)
Does anyone know more about these Transistors?
/halo
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