thx Patrick for your reply
I have set It to 1.6 A and I hear Improvement
why +/-16V - Isn't It a much lower
I plan to build Aleph J to try as balanced
have you compared F5 to Aleph J
I have set It to 1.6 A and I hear Improvement
why +/-16V - Isn't It a much lower
I plan to build Aleph J to try as balanced
have you compared F5 to Aleph J
In balanced mode, +/-16V rail is equal to +/-32V singled ended, as the output swing is symmetrical and not ground referenced.
Lowering the rail voltage will allow you to increase bias per device, keeping dissipation to around 32W.
F5 is a different amp to AXJ. Some people like one, some the other.
The only way to find out for yourself is to build both.
Patrick
Lowering the rail voltage will allow you to increase bias per device, keeping dissipation to around 32W.
F5 is a different amp to AXJ. Some people like one, some the other.
The only way to find out for yourself is to build both.
Patrick
I like F5
and will think about your proposal
but how can be two sweet pots for this amp - stock settings and your values
I suppose that you like most yours ?
and will think about your proposal
but how can be two sweet pots for this amp - stock settings and your values
I suppose that you like most yours ?
There are at least 2 others who built the balanced version.
See their reviews or ask them.
I never made any attempt to compare versions.
I never will.
Bit of course there are good reasons why I did what I did.
Patrick
See their reviews or ask them.
I never made any attempt to compare versions.
I never will.
Bit of course there are good reasons why I did what I did.
Patrick
Listening evaluation between FQA12P20C/FQA19N20C & Toshiba 2SJ201/2SK1530
Setup Part 1: FQA/Caddock/Vishay vs. FQA/Holco/Dale MRA5/PRP-cermet trim pot.
Simplified F5 circuit with standard values except for a 2K Vishay bulk metal foil trimpot in lieu of P1/R3 (These are so linear and predictable that I could dial in zero DC offset for easy, frustration-free biasing🙂). Balance of the components are a modified CDP w/ integrated lightspeed attenuator and 95dB full range drivers in a sealed box.
Impression over several weeks:
Relative to each other, the Holco/Dale/PRP resistors are a little brighter, the Caddock/Vishay more neutral. I noticed a small amount of listening fatigue whenever I went more than, say, an hour and a half with the Holco/Dale/PRP’s. This has been absent since implementing the Caddock/Vishay’s.
Setup Part 2: Toshiba/Caddock/Vishay
Impression:
Bottom line: I find myself preferring the Toshiba’s by 10% or so (if I had to put a number on it). Of course, audiophiles tend to spend a lot of time and treasure pursuing that last 10%. The devil is often in the details, so I will attempt to give a more nuanced assessment.
Starting at the low end, the FQA’s are tight and accurate. The Toshiba’s bass notes are also detailed, but with a more supple and sensual quality to them. I find myself preferring the benthic sweetness of the Toshiba’s.
At the top end the FQA’s have great speed and sparkle. The Toshiba’s are a little more laid back. Both are very detailed. I suppose if I solely listened to acoustic guitar then the choice would be difficult.
Most music, though, occurs in the vast mid-range. Here the FQA’s present a deep, quiet, black-hole-like soundstage. However, the Toshiba’s have, at the very bleeding edge of notes, just a bit more information revealing a more complex spatial ambience. The “air” is denser with details and has a sort of cloying effect, pulling you into the music. Live music has never been my cup of tea, but now I find myself listening to an Alison Krause live album just to pick out people in the audience. Playing Keiko Matsui’s “Doll” album, which was a Q-sound recording (psycho-acoustical 3D), was also particularly spooky.
Summary:
“Natural” has been used to describe the Toshiba’s sound and I agree. The FQA’s are very neutral, perhaps to the point of blandness in comparison to the Toshiba’s.
In audio, comparisons are often of the apples to oranges variety. Here, I would say it’s like 2% milk (Toshiba’s) vs. skim milk (FQA’s). Skim milk is very smooth and refreshing. Compared to 2% milk, however, it is perhaps over-refined. Some flavorful complex of protein and milk-fat has been striped away leaving one slightly less satiated.
Even if you’re the type to avoid ‘boutique’ parts, I think the 2SJ201/2SK1530 parts should be strongly considered. But if not, you’ll be plenty happy with the FQA’s.
Setup Part 1: FQA/Caddock/Vishay vs. FQA/Holco/Dale MRA5/PRP-cermet trim pot.
Simplified F5 circuit with standard values except for a 2K Vishay bulk metal foil trimpot in lieu of P1/R3 (These are so linear and predictable that I could dial in zero DC offset for easy, frustration-free biasing🙂). Balance of the components are a modified CDP w/ integrated lightspeed attenuator and 95dB full range drivers in a sealed box.
Impression over several weeks:
Relative to each other, the Holco/Dale/PRP resistors are a little brighter, the Caddock/Vishay more neutral. I noticed a small amount of listening fatigue whenever I went more than, say, an hour and a half with the Holco/Dale/PRP’s. This has been absent since implementing the Caddock/Vishay’s.
Setup Part 2: Toshiba/Caddock/Vishay
Impression:
Bottom line: I find myself preferring the Toshiba’s by 10% or so (if I had to put a number on it). Of course, audiophiles tend to spend a lot of time and treasure pursuing that last 10%. The devil is often in the details, so I will attempt to give a more nuanced assessment.
Starting at the low end, the FQA’s are tight and accurate. The Toshiba’s bass notes are also detailed, but with a more supple and sensual quality to them. I find myself preferring the benthic sweetness of the Toshiba’s.
At the top end the FQA’s have great speed and sparkle. The Toshiba’s are a little more laid back. Both are very detailed. I suppose if I solely listened to acoustic guitar then the choice would be difficult.
Most music, though, occurs in the vast mid-range. Here the FQA’s present a deep, quiet, black-hole-like soundstage. However, the Toshiba’s have, at the very bleeding edge of notes, just a bit more information revealing a more complex spatial ambience. The “air” is denser with details and has a sort of cloying effect, pulling you into the music. Live music has never been my cup of tea, but now I find myself listening to an Alison Krause live album just to pick out people in the audience. Playing Keiko Matsui’s “Doll” album, which was a Q-sound recording (psycho-acoustical 3D), was also particularly spooky.
Summary:
“Natural” has been used to describe the Toshiba’s sound and I agree. The FQA’s are very neutral, perhaps to the point of blandness in comparison to the Toshiba’s.
In audio, comparisons are often of the apples to oranges variety. Here, I would say it’s like 2% milk (Toshiba’s) vs. skim milk (FQA’s). Skim milk is very smooth and refreshing. Compared to 2% milk, however, it is perhaps over-refined. Some flavorful complex of protein and milk-fat has been striped away leaving one slightly less satiated.
Even if you’re the type to avoid ‘boutique’ parts, I think the 2SJ201/2SK1530 parts should be strongly considered. But if not, you’ll be plenty happy with the FQA’s.
I think that's pretty observant. My own experience is very
similar, and I have a slight preference for the Vishay/Toshiba
also.
😎
similar, and I have a slight preference for the Vishay/Toshiba
also.
😎
So..... without going back over the last 65 pages.... where do you get these Toshibas, and what other things do you change?
Fran
Fran
I think you are probably referring to the larger 2nd harmonic
content of the IR's due to the "P channel midband effect" of the
IR parts. This creates a somewhat softer spectral balance and
also some 2nd harmonic.
😎
Yes that is true.Me and my friend liked both transistors but toshiba is faster so it sometimes makes headache.IR is slower(but adds harmonics,it is sweet tho) so it is more listenable for many hours.Toshiba is like race horse.Am i wrong?Thank you
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Thanks for the kind words Tea-Bag...still working on a fresh batch.
After NP's endorsement I gotta double time...
After NP's endorsement I gotta double time...
As I am gathering the parts for the F5 with Toshibas, I will risk being rude and ask away. Would you Mr Pass care to share the details of your Toshibas implementation of F5? I know you always say to try it for yourself, but this is my first BIG project, do not want to fry them transistors... Thank you.
😱
I am just wondering how the super-symmetric version compares to the circlotron version.
Has anyone built both?
If so, what are the differences in sound?
Has anyone built both?
If so, what are the differences in sound?
Mr Pass has gone fishing and i can answer these easy questions 😀 Do not worry.Just decrease the gate voltages to zero and then replace IRFP's with toshiba transistors.And adjust bias to 1.3amperes and it makes gate voltage at about 2.7volts.It will work well then.No need to change anything.If you want a better sound you can increase bias from 1.3 amperes to 1.5 amperes.ıt will be better for low impedance speakers.But do not go over this current.If you want to increase current to about 2amperes you should decrease voltage to 18 volts.Use big heatsinks.
You have to touch it for 5 seconds.That is all
In addition to umut1001's suggestions, replace R3/R4 with 1k thru 1.5k for easier adjustment of output bias...I say 1.5k will make for smoother adjustment.
Hints on Toshibas ....
Now why do I want to touch it for 5 seconds? 😕
Kidding, kidding....
Thanks gentlemen for the hints, they are very much appreciated. I shall still read the whole threads on F5, both building and tweaking (it will be a long read to do). I promise to report back in a few years when the amp is finished.
Now why do I want to touch it for 5 seconds? 😕
Kidding, kidding....
Thanks gentlemen for the hints, they are very much appreciated. I shall still read the whole threads on F5, both building and tweaking (it will be a long read to do). I promise to report back in a few years when the amp is finished.
Woohow years 😀 A snail can finish this amplifier in a month i think lol but i did not put it in a case yet.So i am slower than a snail hehehe