Hey Arthur- I'm going to run my F4 naked as well. It'll leave me with a few spare Toshiba jfets, which won't be a bad thing. I will definitely carefully measure the F4 pots before installation, and be sure I know what value theyre at on first startup. I would hate to fry the carefully matched fets from Buzz.
Hey Neville - I'm glad to hear your 50K works well
. Where did you place it in the circuit?
Hey Neville - I'm glad to hear your 50K works well
. Where did you place it in the circuit?When I build guitar speakers I allways burn them in with a 20 - 50 Hz signal through a poweramp for at least half a day.
Did any of you think, or did any of you try burning in output caps for the different Pass projects ?
I thougt of the caps in series with a resistor and then sweeping them with signal generator 10 Hz - 30 KHz for some time. That would probably give them a good start.
What do you think ?
Did any of you think, or did any of you try burning in output caps for the different Pass projects ?
I thougt of the caps in series with a resistor and then sweeping them with signal generator 10 Hz - 30 KHz for some time. That would probably give them a good start.
What do you think ?
I've basically listened to 3 amps my entire life. A GFA-555 ( purchased by my dad when I was 4, still in my house to this day ), a Bryston 2B-LP ( bought 8 years ago, just sold ), and numerous GFA-535's, over the past few years. Long before I ever knew of this website I developed the habit of turning my amps on at least an hour before I was going to listen, because I knew they always sounded better when warm. Probably not the case with all amp types, but is, without question, the case for those 3.
Most of the components will change, even slightly, some of their parameters due to warming up.
Some of these parameter changes will change circuit performance.
Some of these changes will be audible.
I put together a Ba-3 FE about a week or two ago.
Reused jfets from another project and the output caps were from my Jfet boz...so they were used as well. All power supply components, mosfets and resistors were new.
I still felt like the sound improved or broke-in dramatically over the following days after completing the build. It felt like the imaging stabilized and the soundstage widened and overall it is a lot more coherent. Initially, I was unimpressed. Now I think it's great.
I don't know if this is mental or something is actually going on...but it's rare that I initially love ANY new equipment, no matter how good. It's like my brain needs to adjust. This is also possibly why few people are impressed with the sound at stores or showrooms...they blame the room but I think it may be the brain trying to adjust to new acoustics.
I do know that the F5 sounds way better after an hour or more or warm up. Sounds best after being on all day. Same with my speakers and phono cartridge. They need some time to loosen up I think.
Reused jfets from another project and the output caps were from my Jfet boz...so they were used as well. All power supply components, mosfets and resistors were new.
I still felt like the sound improved or broke-in dramatically over the following days after completing the build. It felt like the imaging stabilized and the soundstage widened and overall it is a lot more coherent. Initially, I was unimpressed. Now I think it's great.
I don't know if this is mental or something is actually going on...but it's rare that I initially love ANY new equipment, no matter how good. It's like my brain needs to adjust. This is also possibly why few people are impressed with the sound at stores or showrooms...they blame the room but I think it may be the brain trying to adjust to new acoustics.
I do know that the F5 sounds way better after an hour or more or warm up. Sounds best after being on all day. Same with my speakers and phono cartridge. They need some time to loosen up I think.
One thing is warmup and another is break in. I recently read a paper about distortion in capacitors, and there were quite some, more so when they were biased with DC.
But it did not mention break in.
Could be fun if someone with a distortion analyzer ran a test with a new and a broken in capacitor, to see if the spectrum changed. I dont know, but I think so.
I havn´t had the energy yet to set up a PC analyzer, but that should be able to reveal if it is snake oil or not.
But it did not mention break in.
Could be fun if someone with a distortion analyzer ran a test with a new and a broken in capacitor, to see if the spectrum changed. I dont know, but I think so.
I havn´t had the energy yet to set up a PC analyzer, but that should be able to reveal if it is snake oil or not.
@ Hikari 1
Settling down of the new solder joints.
Regarding component beak in, it was put to me by a top designer that as components were new, they had been 'asleep' and that 'break-in' is best thought of as a 'wake-up' period. He also claimed that old (e.g. Mil surplus components) may need extended 'break-in' as they may well have been asleep for a long time!!! Food for thought?
Settling down of the new solder joints.
Regarding component beak in, it was put to me by a top designer that as components were new, they had been 'asleep' and that 'break-in' is best thought of as a 'wake-up' period. He also claimed that old (e.g. Mil surplus components) may need extended 'break-in' as they may well have been asleep for a long time!!! Food for thought?
I thought i'd post a pic of my 99% done BA-3 build.
The white wires lead to the black terminal blocks on the faceplate. They are for bias, DC offset and P3 probes. Makes it really easy and fast to make adjustments.
My goal was to keep signal wire short.
I have no scope or distortion analyzer to scientifically adjust P3. I've tried a few different settings, just by counting the turns of the pot. It has a profound effect. I still don't know where I will leave it but has it really changes the placement and location of instruments and voices. You want it wide and distant with voices deep in the back it can do that. If you want it up front and focused with vocals right above your head but less depth and width it can do that too. If any knows of any Mac based software to take some measurements related to P3 let me know. That may be the next step.
I'd describe the sound as controlled and precise. Smooth and even without any raggedness or sense of being out of control. Compared to my prior preamp, a Jfet BOZ, it is much more refined and extended, image placement is much more solid and it never feels ragged or compressed. But it maintains the same basic tonality.
This is a great design, a relatively easy build even for someone inexperienced like me and sounds great. So far so good.
The white wires lead to the black terminal blocks on the faceplate. They are for bias, DC offset and P3 probes. Makes it really easy and fast to make adjustments.
My goal was to keep signal wire short.
I have no scope or distortion analyzer to scientifically adjust P3. I've tried a few different settings, just by counting the turns of the pot. It has a profound effect. I still don't know where I will leave it but has it really changes the placement and location of instruments and voices. You want it wide and distant with voices deep in the back it can do that. If you want it up front and focused with vocals right above your head but less depth and width it can do that too. If any knows of any Mac based software to take some measurements related to P3 let me know. That may be the next step.
I'd describe the sound as controlled and precise. Smooth and even without any raggedness or sense of being out of control. Compared to my prior preamp, a Jfet BOZ, it is much more refined and extended, image placement is much more solid and it never feels ragged or compressed. But it maintains the same basic tonality.
This is a great design, a relatively easy build even for someone inexperienced like me and sounds great. So far so good.
Attachments
Looks fantastic! Bravo!!
One thing I want to do and just haven't gotten to Radio Shack yet is make a set of shorting RCA for the unused inputs. Take some cheap RCA males, connect the pin to the sleeve and place them on the input jacks.
Also, the Bias needs to be set with the inputs shorted - why, I am not sure, but it is true.
One thing I want to do and just haven't gotten to Radio Shack yet is make a set of shorting RCA for the unused inputs. Take some cheap RCA males, connect the pin to the sleeve and place them on the input jacks.
Also, the Bias needs to be set with the inputs shorted - why, I am not sure, but it is true.
Hik,
is that the Safety Earth under the Power Thermistor?
Bolt the PE wire to the Chassis at the mains input socket.
No other wire comes to this bolt.
Is that purple wire a link to an inter-winding Screen?
Shorten it and bolt it to the Chassis where the wire pokes out of the insulation.
What wire is the Power Thermistor inserted into?
What carries Fault current to Chassis?
Have you tested a Power Thermistor at fault current to see if it can handle 1000Apk?
is that the Safety Earth under the Power Thermistor?
Bolt the PE wire to the Chassis at the mains input socket.
No other wire comes to this bolt.
Is that purple wire a link to an inter-winding Screen?
Shorten it and bolt it to the Chassis where the wire pokes out of the insulation.
What wire is the Power Thermistor inserted into?
What carries Fault current to Chassis?
Have you tested a Power Thermistor at fault current to see if it can handle 1000Apk?
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