My SSE
Here are some photos of my Tubelab SSE. The chasis was a Kenwood tuner and it's struggling to support the weight of the transformers. My first experience with a tube amp. It has been fun to build, and sounds pretty good too. I'm looking to add a motor run cap and will probably upgrade the coupling caps too. I also want to change the cathode resistor to better match the 6550s. I think I prefer them to the EL34.
B+ 453
Cathode Resistor - 560 ohm
JJ El34
Pin 8 Bias - 30.5
Pin 3 Plate - 431
Tug Sol 6550
Pin 8 Bias - 40
Pin 3 Plate - 421
Here are some photos of my Tubelab SSE. The chasis was a Kenwood tuner and it's struggling to support the weight of the transformers. My first experience with a tube amp. It has been fun to build, and sounds pretty good too. I'm looking to add a motor run cap and will probably upgrade the coupling caps too. I also want to change the cathode resistor to better match the 6550s. I think I prefer them to the EL34.
B+ 453
Cathode Resistor - 560 ohm
JJ El34
Pin 8 Bias - 30.5
Pin 3 Plate - 431
Tug Sol 6550
Pin 8 Bias - 40
Pin 3 Plate - 421
Attachments
https://picasaweb.google.com/m/viewer?fgl=true&pli=1#album/kkcinc.kevin/5766965588114380353
This is my sse. I started with 20 watt transcendar opts. I like them because they have all the features like 4,8,16 ohm and ul tap. They also sound very good. I have switched to the big edcors for the bass performance. They also sound good, but the jury is still out. I don't think they are quite as refined sounding as the transcendars, but I'm not sure yet. I will be sticking with the edcors however because I need the extra thump. The transcendars can be used in another project or might be for sale and they are like new.
Under the hood of the hammond box is a triad choke, and Russian pio caps. Also an 100uf hvac auxiliary cap. I have another hammond choke withless henries and resistance that I tried. I can't hear a difference. I have tried audiocap thetas as the couplers and they sound fantastic in this amp. I'll be experimenting with others. Best sounding resistors so far are the carbon comps. Little demons from digikey. Ul triode switch is in the back. Power comes from the allied transformer. I did bypass all electrolytics with .1 uF pios. Not sure if it helped the sound at all, but it is my habit to do so.
I love this amp.
This is my sse. I started with 20 watt transcendar opts. I like them because they have all the features like 4,8,16 ohm and ul tap. They also sound very good. I have switched to the big edcors for the bass performance. They also sound good, but the jury is still out. I don't think they are quite as refined sounding as the transcendars, but I'm not sure yet. I will be sticking with the edcors however because I need the extra thump. The transcendars can be used in another project or might be for sale and they are like new.
Under the hood of the hammond box is a triad choke, and Russian pio caps. Also an 100uf hvac auxiliary cap. I have another hammond choke withless henries and resistance that I tried. I can't hear a difference. I have tried audiocap thetas as the couplers and they sound fantastic in this amp. I'll be experimenting with others. Best sounding resistors so far are the carbon comps. Little demons from digikey. Ul triode switch is in the back. Power comes from the allied transformer. I did bypass all electrolytics with .1 uF pios. Not sure if it helped the sound at all, but it is my habit to do so.
I love this amp.
Sounds way better than it has a right to...
This SSE is my first DIY project. I built it to hear for myself what all the fuss over class A single ended amps and their corresponding back-loaded horns is about. I am pretty well sold. The amp has zero noise and other than fairly weak bass and a little congestion in more complex pieces (I am a headphone guy so take this with a grain of salt - I am used to high degree of clarity), this amp sounds amazing... almost headphone like in its linear presentation, stable imaging and rich soundstage.
My only regret is not holding out for the larger output transformers, George is correct: don't skimp here it is the most difficult thing to upgrade. A bit more bass extension woud be nice but for most music I can live with what the amp offers.
A few vital stats:
Room : About 16' x 19' with ceiling varying from 8' to 9'
Source : #! Linux running MPD > Schiit Bifrost DAC > Tubelab SSE > Madisound BK-16 (back-loaded folded horns) with Fostex FE166En drivers
SSE Amp :
Power Supply : Sovtek 5AR4 Tube Rectifier with 10H-200mA Choke and a giant filter capacitor
Coupling caps : Robert Hovland Super Caps 0.22uF / 600V Film & Foil Poly
Volume Pot : Alps Blue Velvet
Driver Tube : Mullard 12AX7/ECC83 reissue
Power Tubes : Tung-Sol 6550 reissue
OPT's : Edcore GXSE15-8-8K (really should have pinched for the bigger OPT's)
Takman metal film resistors in the signal path
I powered up using some old bookshelf speakers, the results were not music, I didn't expect much but I was honestly a little surprised and worried at just how poor it sounded. The good news was it worked right away, the voltages all checked out and it didn't explode.
Next I hooked up the Fostex drivers to break both amp and drivers in while I built the horn cabinets. This was much more promising, even without drivers I was getting very clear, balanced but weak sound. But wait, where is the noise? This is a tube amp right? Shouldn't there be some noise? Nope, just a faint nothing at full volume with my head right at the driver.
Once I got everything put together (it took a while to get the BK-16's stuffed properly and correctly located in the room) and settled it really plays nice and fills the room quite well. I listen to it critically at nearly full volume, but that is too loud for conversation.
CFB helps anything but very simply instrumented acoustic pieces; the clarity with or without CFB is really astounding on folk, (some types of) jazz, chamber, african, whatever. Most of the time I leave CFB switched on, there is just a bit too much harmonic distortion for me otherwise, too much of that second-order goodness is still, well... too much. I also wired switches for the ultralinear tap, it is a little rough sounding - a lot more volume of course but not something I will use; my curiosity is satisfied though.
The only shortcomings are the bass (bigger OPT's would have been wise, but add considerably to the cost of the build) and a little difficulty resolving very complex music. It does get a little winded on very challenging dynamic pieces, a friend uses a tough piece of vocal jazz as his litmus to test the limitations of audio gear... it really did tax the amp; the imaging and sound stage were spot on but the amp didn't quite have enough speed to keep up with the big (and I do mean BIG) dynamic swings. The music was completely enjoyable but it did show pretty clearly this is not a cost-is-no-object system.
I've been running the system for about 8 months now and I have gotten nothing but surprise and very positive comments on the clarity of this setup from totally HiFi illiterate to very experienced ears. It was a lot of fun to build (thanks for the great design and PCB George) and even more fun to use. For what I have into the amp and speakers it really should not sound as good as it does. For that I consider it a rewarding and resounding success for a first time DIY project.
Next stop : Pass Labs Forum ;-)
This SSE is my first DIY project. I built it to hear for myself what all the fuss over class A single ended amps and their corresponding back-loaded horns is about. I am pretty well sold. The amp has zero noise and other than fairly weak bass and a little congestion in more complex pieces (I am a headphone guy so take this with a grain of salt - I am used to high degree of clarity), this amp sounds amazing... almost headphone like in its linear presentation, stable imaging and rich soundstage.
My only regret is not holding out for the larger output transformers, George is correct: don't skimp here it is the most difficult thing to upgrade. A bit more bass extension woud be nice but for most music I can live with what the amp offers.
A few vital stats:
Room : About 16' x 19' with ceiling varying from 8' to 9'
Source : #! Linux running MPD > Schiit Bifrost DAC > Tubelab SSE > Madisound BK-16 (back-loaded folded horns) with Fostex FE166En drivers
SSE Amp :
Power Supply : Sovtek 5AR4 Tube Rectifier with 10H-200mA Choke and a giant filter capacitor
Coupling caps : Robert Hovland Super Caps 0.22uF / 600V Film & Foil Poly
Volume Pot : Alps Blue Velvet
Driver Tube : Mullard 12AX7/ECC83 reissue
Power Tubes : Tung-Sol 6550 reissue
OPT's : Edcore GXSE15-8-8K (really should have pinched for the bigger OPT's)
Takman metal film resistors in the signal path
I powered up using some old bookshelf speakers, the results were not music, I didn't expect much but I was honestly a little surprised and worried at just how poor it sounded. The good news was it worked right away, the voltages all checked out and it didn't explode.
Next I hooked up the Fostex drivers to break both amp and drivers in while I built the horn cabinets. This was much more promising, even without drivers I was getting very clear, balanced but weak sound. But wait, where is the noise? This is a tube amp right? Shouldn't there be some noise? Nope, just a faint nothing at full volume with my head right at the driver.
Once I got everything put together (it took a while to get the BK-16's stuffed properly and correctly located in the room) and settled it really plays nice and fills the room quite well. I listen to it critically at nearly full volume, but that is too loud for conversation.
CFB helps anything but very simply instrumented acoustic pieces; the clarity with or without CFB is really astounding on folk, (some types of) jazz, chamber, african, whatever. Most of the time I leave CFB switched on, there is just a bit too much harmonic distortion for me otherwise, too much of that second-order goodness is still, well... too much. I also wired switches for the ultralinear tap, it is a little rough sounding - a lot more volume of course but not something I will use; my curiosity is satisfied though.
The only shortcomings are the bass (bigger OPT's would have been wise, but add considerably to the cost of the build) and a little difficulty resolving very complex music. It does get a little winded on very challenging dynamic pieces, a friend uses a tough piece of vocal jazz as his litmus to test the limitations of audio gear... it really did tax the amp; the imaging and sound stage were spot on but the amp didn't quite have enough speed to keep up with the big (and I do mean BIG) dynamic swings. The music was completely enjoyable but it did show pretty clearly this is not a cost-is-no-object system.
I've been running the system for about 8 months now and I have gotten nothing but surprise and very positive comments on the clarity of this setup from totally HiFi illiterate to very experienced ears. It was a lot of fun to build (thanks for the great design and PCB George) and even more fun to use. For what I have into the amp and speakers it really should not sound as good as it does. For that I consider it a rewarding and resounding success for a first time DIY project.
Next stop : Pass Labs Forum ;-)
Attachments
Pics of my SSE
Hello, fellow Tubelab builders. I thought I'd share a few pics of my SSE as it looks different to most I've seen here. It has the 25w Edcor opt's, gold lion KT88's from Jim McShane, and 5ar4 rectifier. 200ma choke and 70uf motor run aux cap. B+ is 460 volts with switchable 560/710 ohm resistors for KT88/EL34 respectively. In a previous life the case was a "sound reproducer" in a large cinema projector. The idea behind this layout is to keep all the high voltage stuff out of reach of our 1 year old son who likes to "whack" things. The thought of him smashing a tube and getting fried meant I needed to make this amp safe or sell it. It sounds way too good to sell, so this is the result. All up, around Aus$1000 in parts, (shipping the trafo's was a killer!) It's easily the most satisfying thing I've built so far. There's a few loose ends to tidy up still, maybe next weekend..
A big thankyou to George for making this great board avaliable!
Best regards, Pete. ps I hope the photos work..
IMG_1451.JPGIMG_1445.JPGIMG_1444.JPG
Hello, fellow Tubelab builders. I thought I'd share a few pics of my SSE as it looks different to most I've seen here. It has the 25w Edcor opt's, gold lion KT88's from Jim McShane, and 5ar4 rectifier. 200ma choke and 70uf motor run aux cap. B+ is 460 volts with switchable 560/710 ohm resistors for KT88/EL34 respectively. In a previous life the case was a "sound reproducer" in a large cinema projector. The idea behind this layout is to keep all the high voltage stuff out of reach of our 1 year old son who likes to "whack" things. The thought of him smashing a tube and getting fried meant I needed to make this amp safe or sell it. It sounds way too good to sell, so this is the result. All up, around Aus$1000 in parts, (shipping the trafo's was a killer!) It's easily the most satisfying thing I've built so far. There's a few loose ends to tidy up still, maybe next weekend..
A big thankyou to George for making this great board avaliable!
Best regards, Pete. ps I hope the photos work..
IMG_1451.JPGIMG_1445.JPGIMG_1444.JPG
SSE pic
Whoops, photo didn't work. Here it is:
photo_zpseb3748b3.jpg picture by discochicken - Photobucket
Whoops, photo didn't work. Here it is:
photo_zpseb3748b3.jpg picture by discochicken - Photobucket
Last pic
Sorry, I'm yet to work out how to attatch pics properly, so it's one-at-a-time
photo3_zps04dc3899.jpg picture by discochicken - Photobucket
Sorry, I'm yet to work out how to attatch pics properly, so it's one-at-a-time
photo3_zps04dc3899.jpg picture by discochicken - Photobucket
Why not upload the pictures to the forum here rather than using a remote host?
To post pictures click "Advanced" and then "Manage Attachments" next look at "Upload files from your computer" and finally click "Browse" - fellow members will thank you down the road a few months from now when those photobucket links are all broken.
To post pictures click "Advanced" and then "Manage Attachments" next look at "Upload files from your computer" and finally click "Browse" - fellow members will thank you down the road a few months from now when those photobucket links are all broken.
Still to have the top-plate finished, and the 45 tubes moved off-board so they don't touch each other, but working nicely!
http://www.flickr.com/photos/jet5/8044501041/in/photostream/lightbox/
http://www.flickr.com/photos/jet5/8044501041/in/photostream/lightbox/
Out the box ... muddy. After 8 hours or so - to my great relief - they opened up, and are now better (marginally but noticably) in every department than the Sylvanias they replaced.
Bottom end is extended and weighty, top now very good indeed ... though I am glad I have supertweeters, because they might not have quite the sparkle to work well with full-rangers.
It is so hard to judge an individual component of a system. BTW they look fantastic!
Completed 300b Tubelab SE
I finally finished my TubeLab SE build (almost a year and half total). Well, mostly finished. I have a blank-off plate where a B- voltage meter will go (I'm thoroughly dissatisfied with the availability of panel meters.) I also have stalled on trying to get a microcontroller setup for voltage/temperature monitoring. Since these items do not affect the function of the amp, I decided to call it done and quit chasing rabbits. Here are some specs:
Hammond Chassis (17"x10"x3") 1441-32
Edcor XPWR131 Power Transformer
100uF 370 volt AC Motor Run Capacitor
Transcendar 10H 100Ohm Choke
Transcendar TT-020-OT 20 Watt OPT (3K to 4, 8, & 16 ohms, 18 Hz to 100 kHz)
Used Raytheon 5842
Guigang 300b (very cheap from eBay)
Sovtek 5AR4
Inverted build (tube sockets on top/components on bottom)
Remote 4-pin sockets for 300b
Fan cooled
By mounting the transformers along the edges of the chassis, I was able to avoid needing reinforcements. The total weight is 34 pounds, and there is no noticeable flexing. I chose this size because the lengthwise dimension (17") is close to standard stereo equipment (plus it gives plenty of room to work). I am using vintage GE panel meters to indicate the bias of the 300b tubes. I used the cheapest nastiest Hong Kong 300b's I could find (I think they were $103 shipped for the pair). I wanted something inexpensive in case I had made any mistakes in construction. My plan, now that the testing phase is complete, is to get better 300b tubes and keep the Guigang tubes as spares. The Transcendar choke is not pretty, so it is mounted to the inside of the chassis (front left - in front of the Edcor power transformer). B+ is 408V, Bias is at 68ma, heat sink with fan on is between 89f and 92f (76f ambient). With the fan off, the amp only runs for about 8 minutes before the regulator shuts down. I'm not 100% pleased with the fan, and it is audible. I have two other fans to try (lower db but also lower static pressure ratings). If I can lower the fan noise, and keep the heat sink under perhaps 110f I'll be happy. The fan is a blower type, and is mounted to the bottom panel. It blows directly on the regulator heat sink, and exits through a hole in the opposite side of the chassis. I'm guessing that the caps and such get some small benefit from the moving air currents (hopefully enough to extend their life). For the power LED, I tapped off the 5VAC heater feed from the transformer. I used a diode in line with a resistor and a small 100uf cap. DC voltage was a little over 7.1V and I used a 560 ohm resistor between that and a green LED.
Connected equipment:
Pioneer PL-540 Turntable
Audio-Technica AT440MLa Cartridge
Hagerman Technology Cornet 2 Phono Stage (built from PCB)
Adcom GTP-500 Pre-Amp
Tri-Trix TL Speakers (89db -boo)
Tivoli Audio subwoofer
My first impressions with this amp once connected to my main speakers were surprising. I've never had the chance to listen to a Single Ended amplifier (or even a DHT for that matter). So it was a leap of faith to build this amp, and I was very concerned about volume levels and bass availability. I knew that my speakers were a poor match (although they do have a fairly flat impedance curve). I had already decided that my next project would be some full range horn speakers just for the TSE. On the first song, I was BLOWN AWAY! Not only was the volume very respectable, the bass was amazing! In fact, there was almost too much bass. Just to be sure, I disconnected my subwoofer. It's no longer needed now. However, there was a problem. My first record was Silversun Pickups / Pikul EP. I kept hearing things that shouldn't be there. At one point, there was some fuzziness where it shouldn't be and at another point the sounds seemed to fade left to right and back. Some instruments sounded harsh, and others sounded thin/reedy. I was deeply worried. I then tried another record (Pink Floyd / Wish You Were Here -reissue). I don't like using words like creamy, sublime, or golden honey to describe music/sounds. But it was. I could close my eyes, and I was in another place. I no longer have any doubts that this was the right amplifier to build. I've since played about 6 or 7 records through the TSE, and overall it sounded amazing. I'm still in shock at both the volume and bass levels. For comparison, my previous amp was a Mark Hill MC-6L6GC (just like a Yaqin MC-5881A) which is a 6L6 push pull tube amp; and a Peter Daniels Chip Amp before that. Connected through the same equipment/speakers the TSE has dominantly better bass than both other amps! I did notice that on fast technical sections of music, the amp did seemed to get tripped up. Thankfully, this only happened once or twice and occurred while playing music that was way too aggressive. There is no hum whatsoever, although I'm sure that my insensitive speakers help here.
I have heard many tales of good audio gear revealing flaws in certain recordings. I have always thought that was rubbish. How can better equipment make something sound worse? But now I know. I'm not sure how I feel about that. On one hand, I like what this amp does to good recordings. On the other hand, it means there are certain albums that will only ever be allowed to play on my older equipment.
In summary, I deeply enjoy the Tubelab SE. I am pleasantly surprised at both the bass and volume levels available. I can't wait to see how it sounds with proper 300b tubes! (any recommendations)? I may in the future see if there is something I can do to shift the tonal balance a little higher (almost too much bass and not enough treble now).
I finally finished my TubeLab SE build (almost a year and half total). Well, mostly finished. I have a blank-off plate where a B- voltage meter will go (I'm thoroughly dissatisfied with the availability of panel meters.) I also have stalled on trying to get a microcontroller setup for voltage/temperature monitoring. Since these items do not affect the function of the amp, I decided to call it done and quit chasing rabbits. Here are some specs:
Hammond Chassis (17"x10"x3") 1441-32
Edcor XPWR131 Power Transformer
100uF 370 volt AC Motor Run Capacitor
Transcendar 10H 100Ohm Choke
Transcendar TT-020-OT 20 Watt OPT (3K to 4, 8, & 16 ohms, 18 Hz to 100 kHz)
Used Raytheon 5842
Guigang 300b (very cheap from eBay)
Sovtek 5AR4
Inverted build (tube sockets on top/components on bottom)
Remote 4-pin sockets for 300b
Fan cooled
By mounting the transformers along the edges of the chassis, I was able to avoid needing reinforcements. The total weight is 34 pounds, and there is no noticeable flexing. I chose this size because the lengthwise dimension (17") is close to standard stereo equipment (plus it gives plenty of room to work). I am using vintage GE panel meters to indicate the bias of the 300b tubes. I used the cheapest nastiest Hong Kong 300b's I could find (I think they were $103 shipped for the pair). I wanted something inexpensive in case I had made any mistakes in construction. My plan, now that the testing phase is complete, is to get better 300b tubes and keep the Guigang tubes as spares. The Transcendar choke is not pretty, so it is mounted to the inside of the chassis (front left - in front of the Edcor power transformer). B+ is 408V, Bias is at 68ma, heat sink with fan on is between 89f and 92f (76f ambient). With the fan off, the amp only runs for about 8 minutes before the regulator shuts down. I'm not 100% pleased with the fan, and it is audible. I have two other fans to try (lower db but also lower static pressure ratings). If I can lower the fan noise, and keep the heat sink under perhaps 110f I'll be happy. The fan is a blower type, and is mounted to the bottom panel. It blows directly on the regulator heat sink, and exits through a hole in the opposite side of the chassis. I'm guessing that the caps and such get some small benefit from the moving air currents (hopefully enough to extend their life). For the power LED, I tapped off the 5VAC heater feed from the transformer. I used a diode in line with a resistor and a small 100uf cap. DC voltage was a little over 7.1V and I used a 560 ohm resistor between that and a green LED.
Connected equipment:
Pioneer PL-540 Turntable
Audio-Technica AT440MLa Cartridge
Hagerman Technology Cornet 2 Phono Stage (built from PCB)
Adcom GTP-500 Pre-Amp
Tri-Trix TL Speakers (89db -boo)
Tivoli Audio subwoofer
My first impressions with this amp once connected to my main speakers were surprising. I've never had the chance to listen to a Single Ended amplifier (or even a DHT for that matter). So it was a leap of faith to build this amp, and I was very concerned about volume levels and bass availability. I knew that my speakers were a poor match (although they do have a fairly flat impedance curve). I had already decided that my next project would be some full range horn speakers just for the TSE. On the first song, I was BLOWN AWAY! Not only was the volume very respectable, the bass was amazing! In fact, there was almost too much bass. Just to be sure, I disconnected my subwoofer. It's no longer needed now. However, there was a problem. My first record was Silversun Pickups / Pikul EP. I kept hearing things that shouldn't be there. At one point, there was some fuzziness where it shouldn't be and at another point the sounds seemed to fade left to right and back. Some instruments sounded harsh, and others sounded thin/reedy. I was deeply worried. I then tried another record (Pink Floyd / Wish You Were Here -reissue). I don't like using words like creamy, sublime, or golden honey to describe music/sounds. But it was. I could close my eyes, and I was in another place. I no longer have any doubts that this was the right amplifier to build. I've since played about 6 or 7 records through the TSE, and overall it sounded amazing. I'm still in shock at both the volume and bass levels. For comparison, my previous amp was a Mark Hill MC-6L6GC (just like a Yaqin MC-5881A) which is a 6L6 push pull tube amp; and a Peter Daniels Chip Amp before that. Connected through the same equipment/speakers the TSE has dominantly better bass than both other amps! I did notice that on fast technical sections of music, the amp did seemed to get tripped up. Thankfully, this only happened once or twice and occurred while playing music that was way too aggressive. There is no hum whatsoever, although I'm sure that my insensitive speakers help here.
I have heard many tales of good audio gear revealing flaws in certain recordings. I have always thought that was rubbish. How can better equipment make something sound worse? But now I know. I'm not sure how I feel about that. On one hand, I like what this amp does to good recordings. On the other hand, it means there are certain albums that will only ever be allowed to play on my older equipment.
In summary, I deeply enjoy the Tubelab SE. I am pleasantly surprised at both the bass and volume levels available. I can't wait to see how it sounds with proper 300b tubes! (any recommendations)? I may in the future see if there is something I can do to shift the tonal balance a little higher (almost too much bass and not enough treble now).
Nice build acceler8 
I cannot enlarge the pictures... is it just my browser?
There are many affordable 300B options:
Electro Harmonix gold pin
JJ
Gold Lion
Full Music
Psvane
They range from $150 to $300 /pair
You can get them from parts connexion for example.
There are many other options when money is no object.
I cannot enlarge the pictures... is it just my browser?There are many affordable 300B options:
Electro Harmonix gold pin
JJ
Gold Lion
Full Music
Psvane
They range from $150 to $300 /pair
You can get them from parts connexion for example.
There are many other options when money is no object.
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Nice build acceler8
Sorry, I pasted the thumbnail links by mistake. Can't edit my post, so I'll repost the photos (hopefully the right links this time).
This is one of the best looking amps I have seen. What are the chances you took build pics? If you did I am sure I am not the only one who would like to see how you built this amp chassis.
My Tubelab SE 300B
Two years and 3 months had passed since ordering my board from George. I finally got the time to build and finished my amp. Nothing fancy, just straight forward TSE 300B.
Some pics with its SSE brother. Picture two shows the provision for connecting DVM (back of 300B sockets) to adjust the current of the output tubes. Potentiometers are below the holes closest to the 5842 input tube for each channel.
Two years and 3 months had passed since ordering my board from George. I finally got the time to build and finished my amp. Nothing fancy, just straight forward TSE 300B.
Some pics with its SSE brother. Picture two shows the provision for connecting DVM (back of 300B sockets) to adjust the current of the output tubes. Potentiometers are below the holes closest to the 5842 input tube for each channel.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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Is power transformer same orientation as output transformers? If it is, it should be rotated 90d.
Hello,
Thanks for your concern, but it is not an issue fortunately. I have 0.6mVAC residual voltage at the speaker terminals of the output transformer closest to the PT even when preamp set to almost max (I can barely reach half and it's very loud already at normal listening sessions). I am using 101dB speakers and there's a low hum when I put my ear as close to the driver as possible, from there as I move away about a foot, it is quiet.
Again, thank for your concern.
Abe
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