t. said:
The caps are always going to be the limitation of the T amp. Just compare a transformer-coupled tube amp with a cap-coupled tube amp. There's no comparison.
I have two AMP3 kits I haven't gotten around to. I hope to make one without coupling caps. Without a "reference amp" I won't know what the improvement is.
thomaseliot said:I own both Ucd180ad and Tripath Ta2022 2x50W 8ohm. I've too a couple of t-amps and a Tripath TA0102a 2x100W 8ohm amp.
Low power Tripath chips can't compete with higher power ones: I have Fostex FE206E 96dB sensitivity and t-amps sound loud enough to shake windows, but with high power tripath chips higher and lower dynamic extension are dramatically improved, while sound quality and detail is similar to t-amps, but with more solid sound.
Please, don't ask who's the winner between Tripath and UCD. More useful to discussion is to tell what are good experiences with both.
UCD is unbeatable for clean sound and timber fidelity of instruments (I listen to classic music only): it is like a good valve amp but quieter. I identify this amp with solo violin sonatas and Bach.
Tripath high power amps are unbeatable for dynamic extension, transients and detail: they go lower and higher than UCD and in between it looks like there are more sounds. When the bass section of an orchestra is sounding loud with thick basses, you can still hear distinctly a violins pizzicato at right volume, and the sudden hit of a timbals or drums still detaches from this loud background with great force.
I use UCD when I want fidelity, Tripath when I want live emotions.
P.S.
I'm the guy with 106 MPP cores, 60 perm, 13 turnsI calculated with a software that they don't saturate.
Thanks for letting us know thomaseliot
Are these MPP cores available?
Well you have to bear in mind that the UCD modules' power ratings are specified into 4ohms, and thus the UCD180 cannot be considered a power monster. Rather go for UCD400 for a better comparison when it comes to dynamic extension and such.
Winding your own cores isn't a terribly good idea. The windings have to be coupled very close to the core for optimal coupling, and any crosscoupling of the windings lead to interwinding capacitance. That's also the reason why toroids aren't preferred since the shape of the toroid makes it difficult to create an even spacing and coupling of the thick wire. Bar cores wind easily, but are not very efficient due to the large air gap, and thus you often need multiple winding layers leading to... capacitance again. That is why the potted cores work the best, or otherwise the SMD ones I mentioned earlier. Merely calculating that the cores don't saturate is only one of the factors that need to be calculated.
Since parasitic elements are usually very small measuring it isn't easy; so unless the specs are published it is best to rather follow the guidelines for what arrangement works best than try and measure what you have.
Winding your own cores isn't a terribly good idea. The windings have to be coupled very close to the core for optimal coupling, and any crosscoupling of the windings lead to interwinding capacitance. That's also the reason why toroids aren't preferred since the shape of the toroid makes it difficult to create an even spacing and coupling of the thick wire. Bar cores wind easily, but are not very efficient due to the large air gap, and thus you often need multiple winding layers leading to... capacitance again. That is why the potted cores work the best, or otherwise the SMD ones I mentioned earlier. Merely calculating that the cores don't saturate is only one of the factors that need to be calculated.
Since parasitic elements are usually very small measuring it isn't easy; so unless the specs are published it is best to rather follow the guidelines for what arrangement works best than try and measure what you have.
t. said:
Thanks for letting us know thomaseliot
Are these MPP cores available?
You can buy small quantities online from following:
http://www.coilws.com/c_winding_main/Powder_Core_types.php
https://www.arnoldmagnetics.com/v2/sales/Product.aspx?id=164
Cost is about $3 each. They sell wire too.
Here you'll find software:
http://www.mag-inc.com/software/software.asp
Since upgrading the UCD's PSU (thanks Chris ) changing the AD8620 to LM4562, changing the resistor biasing the zeners in the regulation circuit to CRD's, changing the cap in the output filter the UCD's performance has really improved in my setup
Both the coupling caps and psu upgrade improved the Amp6.
I'll give these coils a try if I can get chance order some just to see if they improve this amps performance
) changing the AD8620 to LM4562, changing the resistor biasing the zeners in the regulation circuit to CRD's, changing the cap in the output filter the UCD's performance has really improved in my setupBoth the coupling caps and psu upgrade improved the Amp6.
I'll give these coils a try if I can get chance order some just to see if they improve this amps performance
PWatts said:
UCD180 are 2 mono ~90W 8ohm, twice TA2022 and same as TA0102A. I read somewhere that there's no difference between UCD180 and UCD400 in small rooms like mine (16 square meters). Jan-Peter agreed. In larger rooms and less than 96dB speakers I don't know.
In another thread I was the volunteer for this experiment, just executed other members hints.
Experiments are still in progress, when I've time, but this is a good one with respect with T80 low perm 36 turns 1mm wire. I'd like to try lower perm MPP with more turns of smaller wire.
t. said:Since upgrading the UCD's PSU (thanks Chris
I have the Hypex supply HG, so nothing to upgrade for the PS. What output caps you used?
LM4562 is an upgrade for AD8620 on the UCD modules? I payed already for AD8620 upgrade with respect with standard opamps
For Amp6 I think the best improvement would be.... power. So strange, but I've tried Tripath chips with 5w, 45w and 100w and, while sound character is similar, thikness and dynamics grows up greatly an proportionally.
Think that Audio Research made e 2x150W Tripath based amp, and one year later, after customers requests, 2x300W. Belcanto started from 2x100w to go to 2x500w bridged.
thomaseliot said:
I have the Hypex supply HG, so nothing to upgrade for the PS. What output caps you used?
LM4562 is an upgrade for AD8620 on the UCD modules? I payed already for AD8620 upgrade with respect with standard opamps
I use PPS caps and lowered them to 470nf
The LM4562 is much better than the AD8620 IMHO
I know the HG is a good supply but the T-network caps are better than those normal Slitfoils
phn said:
"Caught fire" might be the right phrase.
I remember that thread. That modification is beyond what most of the T-Amp modders can do. Most of them are new at this; this is often a 1st project. That's probably why it didn't go anywhere.
Going in behind the input opamps is a good and clever idea, but it requires a lot of circuit juggling. The risk of noise and high DC offset is not worth it to most builders.
No need for $40 cap. There are some very nice ones out there for $5 or less that make for a good sounding, reliable input circuit. It just comes down to what is practical for most builders.
panomaniac said:
True. I wrote "hope" because I'm not sure I'm up to it. And I'm no longer the miserable noob I was when I joined this forum. I'm now a very content hack. (Since I'm very aware of how frustrating it can be to know nothing, I'm probably guilty of talking down to people. But I rather explain something too detailed than leave somebody hanging.)
On the other hand, isn't that what this forum is about--to learn? I think we should be able to pull this off. At worst we will fry a couple of T amps.
I would be willing to try this on an AMP3 I just finished. It seems fairly simple to do and its no big deal if I fry the amp. The biascap on the TA2021B is pin 16 if anyone else wants to give it a try.
The only problem is I don't have any 8v zener diodes. I doubt the local ratshack carries them and I'm not going to place an order with anyone for a few cents worth of diodes.
The only problem is I don't have any 8v zener diodes. I doubt the local ratshack carries them and I'm not going to place an order with anyone for a few cents worth of diodes.
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