the Vbe multiplier applies a "voltage".
You can monitor this voltage and see it changing as you adjust the Variable resistor (2 lead pot).
If you monitor the Vre with a second DVM you will see that this only starts moving when the Multiplier voltage reaches that required to "turn on" the output devices.
Andrew, I understand the operation of the Vbe multiplier, I was just surprised it was so "Off" at the 500 ohm starting position. I didn't count turns, but it seemed like close to 10 turns until I got my first sign of bias current. Other amps I've built the bias started to come up within a turn or two. Of course I may have had 10 turn pots in the Leach. 🙄
I pointed this out so that first timers would understand that the adjustment takes a while to get going. Once bias comes up, it's about 3 turns to a stable 45 mV across the test points. I let it sit for 45 minutes after my last adjustment to verify it was stable and the heat sinks had reached normal operating temperature.
From a cold start setting about 35 mV across the test points will end up with about 45 mV when warmed up. My sinks started out at 68° F and ended up at 89° F dissipating 34.5W. That makes the store 4U case sinks .32C/W Pretty close to advertised, and will probably get better with higher delta-T.
I pointed this out so that first timers would understand that the adjustment takes a while to get going. Once bias comes up, it's about 3 turns to a stable 45 mV across the test points. I let it sit for 45 minutes after my last adjustment to verify it was stable and the heat sinks had reached normal operating temperature.
From a cold start setting about 35 mV across the test points will end up with about 45 mV when warmed up. My sinks started out at 68° F and ended up at 89° F dissipating 34.5W. That makes the store 4U case sinks .32C/W Pretty close to advertised, and will probably get better with higher delta-T.
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Very cool Bob! Can't wait to hear your impressions once you've had a chance to really give it a listen.
Blessings, Terry
Blessings, Terry
Ahh, the hazards of trying work at home with a new amp...
Listening impressions of the Honey Badger vs Leach (Jens' 5 output pair boards) Source BDP-103 feeding amp directly through its analog outputs, crossed to IB sub at 60 Hz by BDP-103. Speakers Zaph design using W15CY001 and TC25001, 8' away spaced 6' apart. Other than SACD all music is ripped to hard drive in FLAC level 0.
Both amps fed by an Avel 600VA 40V toroid through separate power supplies with MUR2020 bridge and 30K uf each channel. Both amps use MJ15034/5 and NJW0281/0302. The HB uses the recommended Toshibas in the VAS and the Leach MJE340/35 (also as the first stage of the output triple).
The differences are subtle, and may be due to faulty audio memory since I don't have a way to quickly change amps. The HB seems to reproduce a bit more low level detail - for example I hear more harmonics on extended bass notes, like in Dire Straits' "Money for Nothing" and Acoustic Alchemy's "Columbia". As a wannabe bassist, I like that.
This seems to translate into a bit of sibilance that I have not heard before on high level cymbal notes. Lower level notes sound like I am in the room with the cymbal so it may be a more accurate rendition of the recorded signal.
On the Yes "Close to the Edge" SACD the image differences are pretty significant. Both amps give a sound field approaching 180° wide, but with the HB the band is pretty much between and in front of the speakers to my toes. With the Leach, the band seems to extend 20° beyond the speakers pretty often and sounds appear to be coming from further back to in my lap. The psychedelic swimming sound sources with the Leach weren't there with the HB, but instruments seemed more defined.
HD Tracks versions of some of Susan Tedeschi, Spira Gyra and Warren Zevon all sounded great with nice imaging, but they don't have the sound field of CTTE.
Winner? Not sure/ different but both good. Will listen to the HB a bit longer and play with input stage bias to see what if any effect it has on the sibilance. That's really the only negative I have with the HB - it may be too accurate. 😉 Bothers in Arms playing while I type, and I am happy with the sound.
OS - there was a tradition of showing freshly built speakers with socks included a few years back. Thought I'd try to bring it back. 😉 Size 15 for those who don't know how big a 4U enclosure is.
Listening impressions of the Honey Badger vs Leach (Jens' 5 output pair boards) Source BDP-103 feeding amp directly through its analog outputs, crossed to IB sub at 60 Hz by BDP-103. Speakers Zaph design using W15CY001 and TC25001, 8' away spaced 6' apart. Other than SACD all music is ripped to hard drive in FLAC level 0.
Both amps fed by an Avel 600VA 40V toroid through separate power supplies with MUR2020 bridge and 30K uf each channel. Both amps use MJ15034/5 and NJW0281/0302. The HB uses the recommended Toshibas in the VAS and the Leach MJE340/35 (also as the first stage of the output triple).
The differences are subtle, and may be due to faulty audio memory since I don't have a way to quickly change amps. The HB seems to reproduce a bit more low level detail - for example I hear more harmonics on extended bass notes, like in Dire Straits' "Money for Nothing" and Acoustic Alchemy's "Columbia". As a wannabe bassist, I like that.
This seems to translate into a bit of sibilance that I have not heard before on high level cymbal notes. Lower level notes sound like I am in the room with the cymbal so it may be a more accurate rendition of the recorded signal.
On the Yes "Close to the Edge" SACD the image differences are pretty significant. Both amps give a sound field approaching 180° wide, but with the HB the band is pretty much between and in front of the speakers to my toes. With the Leach, the band seems to extend 20° beyond the speakers pretty often and sounds appear to be coming from further back to in my lap. The psychedelic swimming sound sources with the Leach weren't there with the HB, but instruments seemed more defined.
HD Tracks versions of some of Susan Tedeschi, Spira Gyra and Warren Zevon all sounded great with nice imaging, but they don't have the sound field of CTTE.
Winner? Not sure/ different but both good. Will listen to the HB a bit longer and play with input stage bias to see what if any effect it has on the sibilance. That's really the only negative I have with the HB - it may be too accurate. 😉 Bothers in Arms playing while I type, and I am happy with the sound.
OS - there was a tradition of showing freshly built speakers with socks included a few years back. Thought I'd try to bring it back. 😉 Size 15 for those who don't know how big a 4U enclosure is.
2.2 -2.4 V across the Vbe is where the OP's start to conduct.
That equates to about halfway on the 500R trimmer(NJWxxxx). The reason for
this large range in Vbe is not all OP's are equal.
I used Sanken devices and they were 7-8 turns away from the ON's ... so
the greater range will accommodate many types of outputs.
You were using the 25 turn trimmers, correct ?
OS
Yes, per your Mouser BOM. I only omitted parts I had on hand already.
I've since found a number of tracks with high level cymbals with no sibilance, must have been the earlier recordings.
I've since found a number of tracks with high level cymbals with no sibilance, must have been the earlier recordings.
Hi Bob,
I noticed sibilance on my HB at first too but it lessened the more I played it. Maybe some of the components just need to burn in. I have been busy the last few days doing A/B testing with all my amps. I hadn't listened the the Low TIM in a while. Mine has just slightly less bass emphasis than most of my other amps. The Leach Superamp is very close to the HB but the HB has a lot more gain. I suffered for the memory thing too until I built a dual volume box and speaker switch so I could instantly switch between amps.
Blessings, Terry
I noticed sibilance on my HB at first too but it lessened the more I played it. Maybe some of the components just need to burn in. I have been busy the last few days doing A/B testing with all my amps. I hadn't listened the the Low TIM in a while. Mine has just slightly less bass emphasis than most of my other amps. The Leach Superamp is very close to the HB but the HB has a lot more gain. I suffered for the memory thing too until I built a dual volume box and speaker switch so I could instantly switch between amps.
Blessings, Terry
sibilance ...
Play around with the TMC feedback resistor.
It is shown as R24 (820R) ... 1k ,1.2k, 1.5k will slightly reduce
LG at high frequencies. I will order 1.2k for mine.
820r also will show (minor) ringing on clip/squarewave.
This is the resistor that makes the HB "too accurate" 😀 .
OS
Play around with the TMC feedback resistor.
It is shown as R24 (820R) ... 1k ,1.2k, 1.5k will slightly reduce
LG at high frequencies. I will order 1.2k for mine.
820r also will show (minor) ringing on clip/squarewave.
This is the resistor that makes the HB "too accurate" 😀 .
OS
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My badger boards are built but moving / rebuilding new house has got in the way :-(
My badgers will be driving a pair of Martin Logan ascents - replacing (if I like them 🙂 a home built Trimodal - which Doug self told me is poorly suited for driving my speakers (but you know what - it sounds awesome ) despite his "sterile low thd blah blah" design.
Cannot wait to try the badgers. I have a nice analyser so can run & post some specs too when I'm done .
Thanks to ostripper
Merry Xmas to all you good forum folk 🙂
Sent from my iPhone using Tapatalk
My badgers will be driving a pair of Martin Logan ascents - replacing (if I like them 🙂 a home built Trimodal - which Doug self told me is poorly suited for driving my speakers (but you know what - it sounds awesome ) despite his "sterile low thd blah blah" design.
Cannot wait to try the badgers. I have a nice analyser so can run & post some specs too when I'm done .
Thanks to ostripper
Merry Xmas to all you good forum folk 🙂
Sent from my iPhone using Tapatalk
Thanks OS. I will probably make that change. Funny that I noticed more detail on the bass harmonics, I didn't increase the subwoofer level to compensate for the increased gain relative to the Leach. I've got Aleph-J and F-5 parts on the bench, I'll be busy this holiday week. Major amp testing.
Terry, my Leach has very good bass extension. I used 470 uf bipolars with 1 uf MKP bypass on the input and feedback positions. It has 10,000 uf per rail on board and 1 uf MKT at each output device. MY HB input cap is a Wima 4.7 uf MKP.
Terry, my Leach has very good bass extension. I used 470 uf bipolars with 1 uf MKP bypass on the input and feedback positions. It has 10,000 uf per rail on board and 1 uf MKT at each output device. MY HB input cap is a Wima 4.7 uf MKP.
Hi Bob,
I really can't remember what components I used in the Leach. I know the big caps on board are 18,000uf each so 36,000uf per channel on board and I used a regulated front end and two bridges driving two 24,000uf caps per channel, all driven from a Hafler P230 transformer at around +-65V rails. I should probably revisit the Low TIM sometime. I runs hotter than any of my other AB amps. It is possible that I have the bias set higher than it needs to be.
I really can't remember what components I used in the Leach. I know the big caps on board are 18,000uf each so 36,000uf per channel on board and I used a regulated front end and two bridges driving two 24,000uf caps per channel, all driven from a Hafler P230 transformer at around +-65V rails. I should probably revisit the Low TIM sometime. I runs hotter than any of my other AB amps. It is possible that I have the bias set higher than it needs to be.
And I gave a method that allows any beginner to "see" the effect of making that adjustment immediately
That allays the fear they are doing something wrong.
Whether the bias starts up soon, or later, depends on the choice of resistors ratios. The designer and/or builder can choose many different ratios.
Monitoring the Vbe multiplier voltage shows the effect.
Differences between PCB v2.0 and current version 2.4
Hi all,
I purchased version 2.0 boards for an HB build and got busy with work and life - never started the amp. I have more time in the evenings this winter and plan to build me a Honey Badger in the new year. The store now offers ver 2.4 boards. What are your thoughts on buying the newer boards vs using the ver 2.0s? I don't like to waste money, but want my amp to be as good as possible.
Thanks and happy holidays,
Ralph
Hi all,
I purchased version 2.0 boards for an HB build and got busy with work and life - never started the amp. I have more time in the evenings this winter and plan to build me a Honey Badger in the new year. The store now offers ver 2.4 boards. What are your thoughts on buying the newer boards vs using the ver 2.0s? I don't like to waste money, but want my amp to be as good as possible.
Thanks and happy holidays,
Ralph
The 2.0 is basically the same as the V2.4.
You might want to check the top side traces to ensure continuity (and
jumper if not).
The baker clamp diode CAN be added to older versions (on the board bottom).
The only other changes are totally superficial , silkscreen/baker clamp/
mounting holes.
OS
Thanks
Thanks Ostripper, that's great, I'll just carefully check my boards and get the parts ordered
Ralph
Thanks Ostripper, that's great, I'll just carefully check my boards and get the parts ordered
Ralph
Hi OS,
Can you run down the changes you decided on as to the baker clamp and I think there was one other change. I have some time now to dig back into the HB and I would like to take care of those things. I looked back through the tread but couldn't find it.
Thanks, Terry
Increase the TMC feedback resistor to 1.2K - 1.5K (R24).
Baker clamp diode goes from Q10 -C (anode of diode) to Q9- B (cathode of diode).
That's it.
OS
Baker clamp diode goes from Q10 -C (anode of diode) to Q9- B (cathode of diode).
That's it.
OS
Do you remember what diode you used? You guys were going back and forth on what would be best.
thanks
thanks