230ohms of primary resistance should allow an T500mA fuse to survive many cold restarts.
That T500mA fuse suits any toroid of 35VA or less.
It should NOT blow a T2A fuse which is far too big for a 15VA transformer.
I´ll use this one.
100% Aluminium DIY Box / Case Round Corners 272x212x60mm Silver - Audiophonics
100mAT and no blow, no problem after several on/off! Perhaps after one week self healed X2 filter capacitors?
LED not selected: V- = -16.86VDC and V+ = +16.95VDC without load.
JP
100% Aluminium DIY Box / Case Round Corners 272x212x60mm Silver - Audiophonics
100mAT and no blow, no problem after several on/off! Perhaps after one week self healed X2 filter capacitors?
LED not selected: V- = -16.86VDC and V+ = +16.95VDC without load.
JP
Attachments
I just fired up the audio precision and measured some 20-22uf caps for distortion. The THD VS Level curves look similar but if you look at the spectrum you see the bipolars are about 3 dB lower second harmonic. I think Bob Cordell found something similar if remember correctly.
Decades ago by Cyril Bateman :
Cyril Bateman's Capacitor Sound articles | Linear Audio NL
https://linearaudio.nl/sites/linear...0 to 100uF caps and 100 Hz measurements_0.pdf
Patrick
Cyril Bateman's Capacitor Sound articles | Linear Audio NL
https://linearaudio.nl/sites/linear...0 to 100uF caps and 100 Hz measurements_0.pdf
Patrick
Hello guys.
I have my Whammy done.
But i have some noise at the lower Poti Position.
Its only at a 1/4 Rotation ClockWise an only there.
Sound a Little bit like Tuning in a Radio Station.
Have read a bit and oszillazions could be the issue.
But what to do now?
Change Feedback caps? more or less pf?
Have used the values from the org. schematic and a 50K alps Pot.
thanks for suggestions.
I have my Whammy done.
But i have some noise at the lower Poti Position.
Its only at a 1/4 Rotation ClockWise an only there.
Sound a Little bit like Tuning in a Radio Station.
Have read a bit and oszillazions could be the issue.
But what to do now?
Change Feedback caps? more or less pf?
Have used the values from the org. schematic and a 50K alps Pot.
thanks for suggestions.
Background:
One person's observations on three different class A headphone amps and six different manufactures headphones. The listening observations were made over a period of several days. At age 65 with mild tinnitus and definite high frequency hearing loss these observations should be taken with these facts in mind.
The class A headphone amps are the diy Pass Headphone amp by Wayne (wizard's assistant) at Pass Labs, XRK971's Pocket class A amp, and Salas's DCG3 line and headphone preamp. All three amps where built to the designers BOM. In the PCA by XRK some builders suggested some capacitor changes on the input, output and supply rails I made the changes.
All three of these headphone amps are described on the DIYaudio.com site, so if you want more details seek out those threads.
The source music is "Take Five" by Paul Desmond and Dave Brubeck. It is from the 1982 album "Concord on a Summer Night" (live). It was ripped as a Flac and played directly from a Dell computer using that device's output. No outboard DAC was used.
The six headphones I used are the Sony MDR-7506, Audio Technica ATH-M50, Ultrasone Pro 750, ThinkSound ON2, HiFiman HE400i, and Status Audio OB-1. Cost of these headphones ranges from 60-400usd. Certainly not high end, but reasonable in price.
Listening note, for each set of headphones listened too I would replace the 9v batteries used in the PCA with fully charged ones.
XRK971 PCA headphone amp
OB1 - bass a little muffled, mids clear not hyped, sound stage reasonable front to back, cymbals muted sounding, no zing. decent sound stage width, not overly bright, clarinet sounds clean and clear.
ON2 - bass more clear, solid, clarinet seems more neutral/natural, more sizzle on cymbals. there is more separation of instruments, nice sound stage, drums are more defined than OB1 phones
HE400i - needs more gain than ON2 or OB1 phones, bass not as much in your face, clarinet and piano are more natural, nice sound stage, piano solo very wide, drum solo is like you were there.
Ultrasone 750 - piano sounds more treble, clarinet also lost some presence, good separation on individual instruments, sound stage not as wide, piano solo not as deep, seems like I am not hearing in overtones, some loss of sizzle on cymbals
MDR7506 - narrow sound stage, bass hyped and muffled sounding, clarinet muffled and close feeling. cymbals muddy, no sizzle. piano sounds constrained. overall feeling is muddy and lack of separation including audience clapping
ATH-M50 - clarinet sounds constrained, bass heavy, lots of it, clarinet feels lost in bass, during lower notes on piano sounds nice and clean, sharp, clear, sound stage wider during piano solo, drum solo wider with nice front to rear depth. sizzle on cymbals, clarinet loses some clarity
Pass DIY headphone amp
HE400i - needs more gain to match over headphones, nice wide sound stage, instruments are placed well with good depth, nice balance and separation, the piano sounds like you are there with overtones and decay, nothing sounds hyped
ON2 - a bit more bass sound, clarinet sounds tighter and appears farther back on stage, nice balance between, piano, drums, bass with sizzle on cymbals, piano brighter than HE400i phones, nice detail on drum solo
Ultrasone 750 - narrow sound stage, piano is constrained sounding, clarinet centered, lacks depth, piano lacks luster with solo in front, drum solo is nice and clear with cymbal clean
OB2 - clarinet muffled somewhat muddy, sound stage lacks depth, lack of clarity in the high notes, drum solo muffled sounding with no sizzle on cymbals, ok sound stage width, crispness lacking in drum solo
ATM-M50 - sound stage feels closed in, bass more present with good depth, clarinet has more range, piano notes more rounded, sound stage improves during piano solo, hand claps sound natural, drum solo opening sounding, real very lifelike
MDR7506 - bass hyped, clarinet and piano slightly muffled, decent width on sound stage, bass overwhelming at times, nice sizzle on cymbals, lack of depth in sound stage, drums lack some midrange.
Salas DCG3 headphone amp
HE400i - wide sound stage, good balance of instruments, clarinet really soars, audience clapping sounds natural, piano has nice tonal balance, a little light on drum solo, nice staging on drum solo. overall a very nice tonal balance
ON2 - bass a bit more pronounced, clarinet brighter sounds closer to listening in person, very good width of sound stage, piano also brighter sounding, drum solo more in your face as if you are present in the audience
Ultrasone 750 - nice balance of instruments, clarinet a little muddy sounding, nice wide sound stage along with nice depth, piano solo a touch bright sounding, drum solo has nice imaging, nice sizzle on cymbals
OB1 - nice separation of instruments, clarinet a little bright, bass slightly pronounced and muffled, wide soundstage, piano seems realistic, though there is some loss of clarity during the drum solo
ATM-M50 - bass has more presence overshadowing the other instruments, sound stage not as wide, bass too dominate during piano solo, piano solo tight, slightly artificial sounding, not melodic, good depth and width on sound stage during drum solo with nice sizzle on cymbals
MDR7506 - narrow soundstage, bass dominates, clarinet sounds natural, piano solo thin sounding, strident, strained, crisp drum sounds with nice sizzle on cymbals.
Observations:
Depending on your requirements any of these three headphone amps sound very good, excluding cases these amps are very affordable, using new parts in my situation costs range from about 50usd to 300usd. Also boards and some parts are included from each of the three designers making the build very easy.
As to the various headphones, the top two for me are the HE400i and ON2. Third would be the OB1. At 60usd a steal. Some of the folks on the PCA/XRK971 thread have created an eq file for those phones that improves the listening pleasure. Bottom of my list are the Sony's. These are going away for me.
I am a fan and user of Massdrop. The Thinksound ON2 came from there at a really nice price. I participated in the Sennheiser HD650 drop and I am looking forward to receiving them in December, I believe that 20000 people participated. Great deal.
Obviously everybody hears differently and has different requirements. Any of these headphone amps would be a delight to own and I thank the designers for their skills and willingness to make them available to the audio masses.
YEMV (your ears may vary)
David
One person's observations on three different class A headphone amps and six different manufactures headphones. The listening observations were made over a period of several days. At age 65 with mild tinnitus and definite high frequency hearing loss these observations should be taken with these facts in mind.
The class A headphone amps are the diy Pass Headphone amp by Wayne (wizard's assistant) at Pass Labs, XRK971's Pocket class A amp, and Salas's DCG3 line and headphone preamp. All three amps where built to the designers BOM. In the PCA by XRK some builders suggested some capacitor changes on the input, output and supply rails I made the changes.
All three of these headphone amps are described on the DIYaudio.com site, so if you want more details seek out those threads.
The source music is "Take Five" by Paul Desmond and Dave Brubeck. It is from the 1982 album "Concord on a Summer Night" (live). It was ripped as a Flac and played directly from a Dell computer using that device's output. No outboard DAC was used.
The six headphones I used are the Sony MDR-7506, Audio Technica ATH-M50, Ultrasone Pro 750, ThinkSound ON2, HiFiman HE400i, and Status Audio OB-1. Cost of these headphones ranges from 60-400usd. Certainly not high end, but reasonable in price.
Listening note, for each set of headphones listened too I would replace the 9v batteries used in the PCA with fully charged ones.
XRK971 PCA headphone amp
OB1 - bass a little muffled, mids clear not hyped, sound stage reasonable front to back, cymbals muted sounding, no zing. decent sound stage width, not overly bright, clarinet sounds clean and clear.
ON2 - bass more clear, solid, clarinet seems more neutral/natural, more sizzle on cymbals. there is more separation of instruments, nice sound stage, drums are more defined than OB1 phones
HE400i - needs more gain than ON2 or OB1 phones, bass not as much in your face, clarinet and piano are more natural, nice sound stage, piano solo very wide, drum solo is like you were there.
Ultrasone 750 - piano sounds more treble, clarinet also lost some presence, good separation on individual instruments, sound stage not as wide, piano solo not as deep, seems like I am not hearing in overtones, some loss of sizzle on cymbals
MDR7506 - narrow sound stage, bass hyped and muffled sounding, clarinet muffled and close feeling. cymbals muddy, no sizzle. piano sounds constrained. overall feeling is muddy and lack of separation including audience clapping
ATH-M50 - clarinet sounds constrained, bass heavy, lots of it, clarinet feels lost in bass, during lower notes on piano sounds nice and clean, sharp, clear, sound stage wider during piano solo, drum solo wider with nice front to rear depth. sizzle on cymbals, clarinet loses some clarity
Pass DIY headphone amp
HE400i - needs more gain to match over headphones, nice wide sound stage, instruments are placed well with good depth, nice balance and separation, the piano sounds like you are there with overtones and decay, nothing sounds hyped
ON2 - a bit more bass sound, clarinet sounds tighter and appears farther back on stage, nice balance between, piano, drums, bass with sizzle on cymbals, piano brighter than HE400i phones, nice detail on drum solo
Ultrasone 750 - narrow sound stage, piano is constrained sounding, clarinet centered, lacks depth, piano lacks luster with solo in front, drum solo is nice and clear with cymbal clean
OB2 - clarinet muffled somewhat muddy, sound stage lacks depth, lack of clarity in the high notes, drum solo muffled sounding with no sizzle on cymbals, ok sound stage width, crispness lacking in drum solo
ATM-M50 - sound stage feels closed in, bass more present with good depth, clarinet has more range, piano notes more rounded, sound stage improves during piano solo, hand claps sound natural, drum solo opening sounding, real very lifelike
MDR7506 - bass hyped, clarinet and piano slightly muffled, decent width on sound stage, bass overwhelming at times, nice sizzle on cymbals, lack of depth in sound stage, drums lack some midrange.
Salas DCG3 headphone amp
HE400i - wide sound stage, good balance of instruments, clarinet really soars, audience clapping sounds natural, piano has nice tonal balance, a little light on drum solo, nice staging on drum solo. overall a very nice tonal balance
ON2 - bass a bit more pronounced, clarinet brighter sounds closer to listening in person, very good width of sound stage, piano also brighter sounding, drum solo more in your face as if you are present in the audience
Ultrasone 750 - nice balance of instruments, clarinet a little muddy sounding, nice wide sound stage along with nice depth, piano solo a touch bright sounding, drum solo has nice imaging, nice sizzle on cymbals
OB1 - nice separation of instruments, clarinet a little bright, bass slightly pronounced and muffled, wide soundstage, piano seems realistic, though there is some loss of clarity during the drum solo
ATM-M50 - bass has more presence overshadowing the other instruments, sound stage not as wide, bass too dominate during piano solo, piano solo tight, slightly artificial sounding, not melodic, good depth and width on sound stage during drum solo with nice sizzle on cymbals
MDR7506 - narrow soundstage, bass dominates, clarinet sounds natural, piano solo thin sounding, strident, strained, crisp drum sounds with nice sizzle on cymbals.
Observations:
Depending on your requirements any of these three headphone amps sound very good, excluding cases these amps are very affordable, using new parts in my situation costs range from about 50usd to 300usd. Also boards and some parts are included from each of the three designers making the build very easy.
As to the various headphones, the top two for me are the HE400i and ON2. Third would be the OB1. At 60usd a steal. Some of the folks on the PCA/XRK971 thread have created an eq file for those phones that improves the listening pleasure. Bottom of my list are the Sony's. These are going away for me.
I am a fan and user of Massdrop. The Thinksound ON2 came from there at a really nice price. I participated in the Sennheiser HD650 drop and I am looking forward to receiving them in December, I believe that 20000 people participated. Great deal.
Obviously everybody hears differently and has different requirements. Any of these headphone amps would be a delight to own and I thank the designers for their skills and willingness to make them available to the audio masses.
YEMV (your ears may vary)
David
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.