IMO, what matters most is the use of Low ESR Low ESL capacitors preferable PEH200 series from RIFA/KEMET.
But BHC/KEMET ALC10C153EF063 does a really good job.
The choice of rectifiers is also important as we want to minimize ringing from the diodes when they turn off.
My experience is that a Low ESR/ESL lets say 30.000uF does a better job than standard capacitors for linear power supply.
We can hear a little better stereo imaging but not that much with the new module as with the old one. Most likely due to better PSRR on the current mirrors and generators.
Actually, the current mirrors and generators is the most expensive section on the TSSA V1.7
So if you ask if i would prefer dual mono over single supply configuration then it is a yes, but if i think it is worth the extra money put in then it is a no when using good quality capacitor with Low ESR/ESL.
- Sonny
Buy list
Dane 2 x TSSA V1.7 - Paid - Shipped
Myint67 2 x BL drive modules, 2 x TSSA V1.7, 1 x softstart
vgeorge 2 x TSSA V1.7 without mosfets ECW20N/P20-Z + Salas 2 x TSSA V1.7 - Paid - Shipped
buzzforb 2 x TSSA V1.7 - Paid - Shipped
pdb 2 x TSSA V1.7 + 2 capkits
Michael G and one of his fellows 6 x TSSA V1.7, 1 x softstart. (He already has 2 running) Paid - Shipped
Stajo 2 x BL drive modules, 4 x TSSA V1.7, 1 x softstart.
Prices:
BL drive module: 84€/channel
TSSA V1.7 1 - 3 pcs: 100€/channel
TSSA V1.7 4 - 10 pcs: 90€/channel
CAPBANK BARE PCB costs 13€/board
CAPBANK complete assemblied : 137€/unit
CAPBANK complete unassemblied : 111€/unit
Softstart inclusive iec inlet, fuse drawer, main switch, illuminated power button: 114€/unit
Dane 2 x TSSA V1.7 - Paid - Shipped
Myint67 2 x BL drive modules, 2 x TSSA V1.7, 1 x softstart
vgeorge 2 x TSSA V1.7 without mosfets ECW20N/P20-Z + Salas 2 x TSSA V1.7 - Paid - Shipped
buzzforb 2 x TSSA V1.7 - Paid - Shipped
pdb 2 x TSSA V1.7 + 2 capkits
Michael G and one of his fellows 6 x TSSA V1.7, 1 x softstart. (He already has 2 running) Paid - Shipped
Stajo 2 x BL drive modules, 4 x TSSA V1.7, 1 x softstart.
Prices:
BL drive module: 84€/channel
TSSA V1.7 1 - 3 pcs: 100€/channel
TSSA V1.7 4 - 10 pcs: 90€/channel
CAPBANK BARE PCB costs 13€/board
CAPBANK complete assemblied : 137€/unit
CAPBANK complete unassemblied : 111€/unit
Softstart inclusive iec inlet, fuse drawer, main switch, illuminated power button: 114€/unit
In the normal DIY section i have posted the front of the BL drive unit.
I will of course put more up here shortly, but the frontend is of course without feedback.
Comments to the frontend:
For the BL drive i have developed a front end which convert a given voltage to current with as low distortion as possible without the use of global feedback.
I ended up having less than 0.001% THD. Which i think i okay.
This low distortion we have in the enhanced diamond buffer but also in the currentmirror. The currentmirror normally lays around 0.025%
A note to the V/I converter:
The currentmirror is only that good if driving into a virtual GND node. In other words into an inverting opamp - discrete or chip solution.
Of course there is more to the circuit than shown here.
Also you will see the schematic of the complete circuit attached. I changed my mind and published it.
I will of course put more up here shortly, but the frontend is of course without feedback.
Comments to the frontend:
For the BL drive i have developed a front end which convert a given voltage to current with as low distortion as possible without the use of global feedback.
I ended up having less than 0.001% THD. Which i think i okay.
This low distortion we have in the enhanced diamond buffer but also in the currentmirror. The currentmirror normally lays around 0.025%
A note to the V/I converter:
The currentmirror is only that good if driving into a virtual GND node. In other words into an inverting opamp - discrete or chip solution.
Of course there is more to the circuit than shown here.
- You need a good current generator with high PSRR and low drift
- U1, U2, U3, U4 is a dual package to lower DC drift
- The powersupply (+/-15VDC) should be a low noise high PSRR type
Also you will see the schematic of the complete circuit attached. I changed my mind and published it.
Has anyone has wondered what the TSSA V!.7 is all about?
Basicly it is a current source with feedback.
With its high current gain and high output current we can skip the standard buffer stage and let the VAS stage drive the speaker directly.
This way we remove a "slow" section in the amplifier, to shorten the signal path.
Have a look at the concept diagram of the TSSA V1.7
Basicly it is a current source with feedback.
With its high current gain and high output current we can skip the standard buffer stage and let the VAS stage drive the speaker directly.
This way we remove a "slow" section in the amplifier, to shorten the signal path.
Have a look at the concept diagram of the TSSA V1.7
Attachments
If we are a bit quiet at the moment, then the reason is that we have 4 projects running.
When we have our website running we will release a paypal coupon code for purchases on the website for the first 14 days. Keep looking back.
- Designing and testing a commercial highend amplifier
- BL drive design and test
- Updating Documentation for BL drive and softstart
- Updating the content of our website for the TSSA amplifier
- Making a web-shop on Mirand Audio – Solidstate designs | Audio amplifiers and DACS
When we have our website running we will release a paypal coupon code for purchases on the website for the first 14 days. Keep looking back.
Simple concepts sometimes take many parts and detailed realization to perfectly housekeep. Later in time we will be happy to listen to it VS your previous. Will 0.4A bias current be representative and recommended?
Hi stajo
The BL drive will arrive tuesday . I have made a flaw In the layout so i needed to do a new run.
But i have more Info later today.
Sent from my iPhone using Tapatalk
Vssa 1.7
I just finished my second Vssa 1.7 amp yesterday, and now they have to compete.
Version 1 : Dual mono supply with 2x 225Va standard open transformer and 2x60000uF Nichicon capbank, Heatsink 0.25C/W pr.modul.. (This version has been my first choise over Hypex Ucd400HXR, Holton HPA-nxV200L R2 Dual Die, Passlabs XA30.5)
Version 2 : 500Va Encapsulated shielded transformer and 2x100000uF Rifa PEH200 capbank, Heatsink 0.25C/W pr.modul..
Both version i biased to 50mA= 1A = About 2x20w Class A..
More to come, stay tuned..
Regards Michael.
Kado-sound
I just finished my second Vssa 1.7 amp yesterday, and now they have to compete.
Version 1 : Dual mono supply with 2x 225Va standard open transformer and 2x60000uF Nichicon capbank, Heatsink 0.25C/W pr.modul.. (This version has been my first choise over Hypex Ucd400HXR, Holton HPA-nxV200L R2 Dual Die, Passlabs XA30.5)
Version 2 : 500Va Encapsulated shielded transformer and 2x100000uF Rifa PEH200 capbank, Heatsink 0.25C/W pr.modul..
Both version i biased to 50mA= 1A = About 2x20w Class A..
More to come, stay tuned..
Regards Michael.
Kado-sound
Hi all.
To those who is not sure about the sonic quality of the amp. Mikelm has written a short review of the Previous version. Migo is in the process of writing about the amp. Also the will come a review from Pinocchio from Canada.
But below is the review of the TSSA V1.6
To those who is not sure about the sonic quality of the amp. Mikelm has written a short review of the Previous version. Migo is in the process of writing about the amp. Also the will come a review from Pinocchio from Canada.
But below is the review of the TSSA V1.6
Hi Sonny and all,
It's been a long time since I had a listened to my TSSA V1.6. The last time I did a comparison between that & my DC linked SE 3 stage mosfet amp the general impression was that my amp sounded superior. Technically it had a much better PSSR and I thought that was the key difference. I planned to build a regulated PSU and compare again . . . but I never got around to it. Both amps were powered with full differential choke regulated power supplies.
However, Since then I have made several significant changes to the mains supply arrangements. I now have the following mains arrangements:
1) 1000VA EI isolation transformer with balanced o/p followed by a simple passive filter.
2) A 500W USP that gives a clean sinewave output at all times.
After much experimentation I came to the simple conclusion that my system sounded best when everything was plugged into the USP. Compared with raw mains this gave a big improvement.
This came as something of a surprise to me as every piece of equipment already had CLC filtration after the bridges and all of the line level things already had mains filtration but never-the-less the improvement with the UPS was very clear.
Adding the 1000VA EI transformer with added filtration upstream brought further improvments.
Today I did another comparison between my own amp & TSSA V1.6 - This time it was a different story.
With this much improved PSU arrangements the previous slightly rough "character" of the TSSA V1.6 has dissappeared. There still seems to be some "character" but it is now much more benign and now for the first time I am beginning to hear just how good this amp can sound. Everything is presented very clearly in a very relaxed way. The imaging seems somewhat more clearly defined than my 3 stage amp.
I will do more listening over the next few days but right now I am enjoying the TSSA V1.6 very much and this is putting two stage amps at the top of my list of priorities
Sonny, I will email you about possible upgrade paths.
cheers
mike
Just to clarify my review above:
My V1.6 is not standard - I have done the following mods.
1) Changed R7 & R8 from 1k to 3k3 thus increasing OLG from about 47db to about 56db
2) Snubberized the rail decoupling caps with 4.7uF + 0.2 R ( an alternative method to Sonny's on V1.7 ).
3) Changed the CCS trimming arrangement.
4) Used Caddock TF020 resistors in the feedback circuit.
As Far as I am aware the V1.7 version has OLG of about 70db which I imagine increases PSRR quite a lot.
Taking all this into account along with my extremely quiet PSU arrangement I imagine that my current version might have progressed 30 - 50% towards the V1.7.
After a day of listening to many different styles of music my enthusiasm of this amp remains and the thoughts about it have clarified.
What this amp does is bring the music to life. The music is projected into the room with a sense of realism that is very engaging and in my experience quite rare. Everything sounds more realistic. Imaging is very good. There is still a little "character" added but this is quite benign. Overall the positive traits exceed the negative ones by a big margin.
I spent the day reading through all the threads about 1.6 & 1.7 and Sonny's website and my thought is that if a really good regulated power supply is partnered with the V1.7 then it will probably rival the Mirand A2 in every way except power output.
I will be upgrading to V1.7
Sonny - I will email you.
My V1.6 is not standard - I have done the following mods.
1) Changed R7 & R8 from 1k to 3k3 thus increasing OLG from about 47db to about 56db
2) Snubberized the rail decoupling caps with 4.7uF + 0.2 R ( an alternative method to Sonny's on V1.7 ).
3) Changed the CCS trimming arrangement.
4) Used Caddock TF020 resistors in the feedback circuit.
As Far as I am aware the V1.7 version has OLG of about 70db which I imagine increases PSRR quite a lot.
Taking all this into account along with my extremely quiet PSU arrangement I imagine that my current version might have progressed 30 - 50% towards the V1.7.
After a day of listening to many different styles of music my enthusiasm of this amp remains and the thoughts about it have clarified.
What this amp does is bring the music to life. The music is projected into the room with a sense of realism that is very engaging and in my experience quite rare. Everything sounds more realistic. Imaging is very good. There is still a little "character" added but this is quite benign. Overall the positive traits exceed the negative ones by a big margin.
I spent the day reading through all the threads about 1.6 & 1.7 and Sonny's website and my thought is that if a really good regulated power supply is partnered with the V1.7 then it will probably rival the Mirand A2 in every way except power output.
I will be upgrading to V1.7
Sonny - I will email you.
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I'm just waiting for my encapsulated transfo from SumR to arrive and I will start the burn-in and then listening. The modules have been installed on heatsink for now. So hopefully soon for the review!
Ciao!
Do
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