Hi Fab - I'm still getting around to my builds as loads of design decisions still to be made 
USSA vs FSSA - can you comment on the amount of global feedback used. I recently listened to an EAR 861 tube amplifier with zero feedback, and found it to be better in the highs with regards to cymbals for example, which shimmered and had more microdetail. My other amplifiers (ncore / First One) use lots of global feedback / current feedback to get their performance measurements... they sounded very similar, apart from in the highs. I think high levels of feedback (for my preferences) might be a disadvantage.
How have you used feedback in your designs, and how audiable/prevalent is say 'shimmer' in either design?
Thanks
USSA vs FSSA - can you comment on the amount of global feedback used. I recently listened to an EAR 861 tube amplifier with zero feedback, and found it to be better in the highs with regards to cymbals for example, which shimmered and had more microdetail. My other amplifiers (ncore / First One) use lots of global feedback / current feedback to get their performance measurements... they sounded very similar, apart from in the highs. I think high levels of feedback (for my preferences) might be a disadvantage.
How have you used feedback in your designs, and how audiable/prevalent is say 'shimmer' in either design?
Thanks
Just received. With thanks
Stretchneck hi.. Tubes generally is both triody softer in effect but also more metallic, and brighter { since they are made of...} making the cymbal sound sparkling and more zing
Not really from the feedback, judging fr ba3. But there is a trick.
Silver ceramic or ceramic cap, with combination of some mylar can however provide that tone. Use "cheaper* carbon resistors on feedback too. Just some thoughts.
Stretchneck hi.. Tubes generally is both triody softer in effect but also more metallic, and brighter { since they are made of...} making the cymbal sound sparkling and more zing
Not really from the feedback, judging fr ba3. But there is a trick.
Silver ceramic or ceramic cap, with combination of some mylar can however provide that tone. Use "cheaper* carbon resistors on feedback too. Just some thoughts.
Hi stretchneckHi Fab - I'm still getting around to my builds as loads of design decisions still to be made
USSA vs FSSA - can you comment on the amount of global feedback used. I recently listened to an EAR 861 tube amplifier with zero feedback, and found it to be better in the highs with regards to cymbals for example, which shimmered and had more microdetail. My other amplifiers (ncore / First One) use lots of global feedback / current feedback to get their performance measurements... they sounded very similar, apart from in the highs. I think high levels of feedback (for my preferences) might be a disadvantage.
How have you used feedback in your designs, and how audiable/prevalent is say 'shimmer' in either design?
Thanks
Extract of the USSA manual:
“ The clipping is soft with rounded corners and is mainly due to the relatively low feedBack factor (about 34dB).”
For the FSSA, as a quick estimate the feedback factor should be about 46dB or so which is still considered a “low” feedback amplifier in my book.
In my opinion USSA5 or 3 being class A have an advantage over the more powerful class AB FSSA if we consider the best natural sound criteria.
However, one objective of the FSSA is to provide a more balanced sound than the comparable design of the FO being found relatively thin in the bass Section and requiring additional capacitor banks to compensate based on the comments from threads on this forum...
Also the jfet input stage - as in the FSSA - is known to provide closer to tube sound than bjt.... USSA3 also has jfet input stage.I hope this helps.
Fab
Last edited:
If you like tube tone. Try a full carbon build. Mylar, silver ceramic, polystyrene caps build.. Like old sansui..what I did to fssa, sansui au555 au777 sounds more tube than tube.. I tried modding using only some metal film polyester cap .. Guess what.. It became modern sound.. My fssa turned out real well. It's the ceramic + carbon that also gives some warmth weight and zing.. Apparentlu
Ussa3 will also sound most musical tube character of the whole lot.. Fab or pinnocchio could comment more on that,
Ussa3 will also sound most musical tube character of the whole lot.. Fab or pinnocchio could comment more on that,
Last edited:
Hi AnthonyA
This is a report from a member on this forum that could also help stretchneck:
https://www.diyaudio.com/forums/solid-state/96192-post-solid-pics-565.html#post5345353
Fab
This is a report from a member on this forum that could also help stretchneck:
https://www.diyaudio.com/forums/solid-state/96192-post-solid-pics-565.html#post5345353
Fab
Thanks Fab,
Let's not lose perspective. Fab designs throw the best image, full big round, well saturated and 3d. That's what's most important imho after owning quite a bit of gears and comparing a whole lot.
In a real live system dog fight.. That what matters. Tone is easily tuned with auxiliary accessories
Do yourself a favor... Spend more effort in doing a solid oversize quality toroid and over spec power supply with this design.. That is without a doubt going to achieve one of the best amp you built, heard or own.. Read Bob cordell power supply thread. I had tried a monster 22000 L 22000 + capacitance multiplier as well.. It's great.
Let's not lose perspective. Fab designs throw the best image, full big round, well saturated and 3d. That's what's most important imho after owning quite a bit of gears and comparing a whole lot.
In a real live system dog fight.. That what matters. Tone is easily tuned with auxiliary accessories
Do yourself a favor... Spend more effort in doing a solid oversize quality toroid and over spec power supply with this design.. That is without a doubt going to achieve one of the best amp you built, heard or own.. Read Bob cordell power supply thread. I had tried a monster 22000 L 22000 + capacitance multiplier as well.. It's great.
Last edited:
Then.... Just buy a great, streamer, dac or source that suites your requirement. It will save tons of money and effort in long run. Expensive start, but ended cheap
I had a tube vocal loving buddy who spent 30 years looking, looking. Eventually I convinced him to just buy gold note ds 10. Which is not tube but sounds like it. Ended the search for pretty much everything and sold of the rest of the unimportant collection..He just say jeebers.. Been looking at the wrong place all the while.. For kicks he also uses solid state amp now and kept the diy 300b for {I spent too much} sake lololol
Most of us forget.. How important the source is as its the brain that shapes everything. Buy the right one... Even how expensive it might seem.
I had a tube vocal loving buddy who spent 30 years looking, looking. Eventually I convinced him to just buy gold note ds 10. Which is not tube but sounds like it. Ended the search for pretty much everything and sold of the rest of the unimportant collection..He just say jeebers.. Been looking at the wrong place all the while.. For kicks he also uses solid state amp now and kept the diy 300b for {I spent too much} sake lololol
Most of us forget.. How important the source is as its the brain that shapes everything. Buy the right one... Even how expensive it might seem.
Thanks All - this is really helpful. I also completely agree with the point about source, made significant difference in my setup. It took me ages to get my digital source to even equal the quality of my old CD player. I struggled for a long time when I made the move to streaming.
I did I install the caps on my first one, bass is prostitious.
I did I install the caps on my first one, bass is prostitious.
HDPLEX chassis, ASROCK Phantom MB, 8086K, Gentoo Player and JCAT USB XE. Going to try HDPLEX Linear at some point. EtherRegen made a good difference for me.
Prior to this I used a NUC with Paul Hynes SR7 running Euphony - also very good, but I wanted a one box solutions.
I preferred both of the above over Allo USB sig powered by shanti, and the top of the line Melco N1Z.
Have a read over on audiophile style. This is the route that most are taking nowadays, K class CPU's definately sound better than cheaper processors due to their better binning.
I think I'm about as far as I can push it without buying a Taiko Extreme or Pink Faun.
Prior to this I used a NUC with Paul Hynes SR7 running Euphony - also very good, but I wanted a one box solutions.
I preferred both of the above over Allo USB sig powered by shanti, and the top of the line Melco N1Z.
Have a read over on audiophile style. This is the route that most are taking nowadays, K class CPU's definately sound better than cheaper processors due to their better binning.
I think I'm about as far as I can push it without buying a Taiko Extreme or Pink Faun.
fredlock,
Ready made option:
Ready-to-Run (RTR) SSR DC Speaker Protection and Delay GB
If you want to build it yourself from PCB and parts, you can check out the Neurochrome Audio Guradian-86 and Guardian-686.
Both of these use solid state relay /MOSFET instead of mechanical relays used in most speaker protection circuits available of AliExpress and eBay.
Ready made option:
Ready-to-Run (RTR) SSR DC Speaker Protection and Delay GB
If you want to build it yourself from PCB and parts, you can check out the Neurochrome Audio Guradian-86 and Guardian-686.
Both of these use solid state relay /MOSFET instead of mechanical relays used in most speaker protection circuits available of AliExpress and eBay.
Last edited:
Fab,
I have a question on a few parts:
- Capacitor position C2 (CD15FD221JO3F) - CAP MICA 220PF 5% 500V RADIAL: Can a Wima 220pF be used, or it should be specifically a Silver Mica capacitor here?
- Capacitors C5, C6 (EKYB630ELL222MM40S) - CAP ALUM 2200UF 20% 63V RADIAL - This is out of stock at Mouser. Can other caps of higher value e.g. 3,300uF be used in these positions? I have a few 80V rated 3,300uF snap-in caps.
- Capacitor C1 (optional) ECW-FD2W105K CAP FILM 1.0UF 10% 450VDC RADIAL - Since this is an input cap, I am guessing the larger values will work too? I see good space on the PCB to accommodate multiple alternatives.
- Capacitors C17, C18 (UKA1H331MPD) CAP ALUM 330UF 20% 50V RADIAL - UKA is out of stock, but UFW1H331MPD is in stock. Any suggestions?
- Q1, Q2, Q5: The manual lists BC546/BC556. I recall a post asking about BC550/560, and you mentioned you will update in the manual - which one is correct
I have a question on a few parts:
- Capacitor position C2 (CD15FD221JO3F) - CAP MICA 220PF 5% 500V RADIAL: Can a Wima 220pF be used, or it should be specifically a Silver Mica capacitor here?
- Capacitors C5, C6 (EKYB630ELL222MM40S) - CAP ALUM 2200UF 20% 63V RADIAL - This is out of stock at Mouser. Can other caps of higher value e.g. 3,300uF be used in these positions? I have a few 80V rated 3,300uF snap-in caps.
- Capacitor C1 (optional) ECW-FD2W105K CAP FILM 1.0UF 10% 450VDC RADIAL - Since this is an input cap, I am guessing the larger values will work too? I see good space on the PCB to accommodate multiple alternatives.
- Capacitors C17, C18 (UKA1H331MPD) CAP ALUM 330UF 20% 50V RADIAL - UKA is out of stock, but UFW1H331MPD is in stock. Any suggestions?
- Q1, Q2, Q5: The manual lists BC546/BC556. I recall a post asking about BC550/560, and you mentioned you will update in the manual - which one is correct
Hi Zia
For capacitor C2 for input filter you can use other cap than silver mica such as Wima FKP type.
For C5 and C6 you can other caps as well such as 3300uf with low ESR and high ripple.
For in put cap C1 you can surely use a better cap as indicated in the manual as long as it is a polypropylene type cap. Since there is no feedback cap you can use a larger value of more easy to obtain.
C17/C18: ok to use UFW but UKW is ok too.
Q1/Q2/Q5: the manual rev 0.2.4 already indicates both pairs that can be used.
As an advise theses changes are minor but I would limit the changes because too many parts changes can result in a slightly different sound than original for better or worse ...
Fab
For capacitor C2 for input filter you can use other cap than silver mica such as Wima FKP type.
For C5 and C6 you can other caps as well such as 3300uf with low ESR and high ripple.
For in put cap C1 you can surely use a better cap as indicated in the manual as long as it is a polypropylene type cap. Since there is no feedback cap you can use a larger value of more easy to obtain.
C17/C18: ok to use UFW but UKW is ok too.
Q1/Q2/Q5: the manual rev 0.2.4 already indicates both pairs that can be used.
As an advise theses changes are minor but I would limit the changes because too many parts changes can result in a slightly different sound than original for better or worse ...
Fab
Last edited: