Thanks.
My way of stating my question was not really clear.I should not have said " as in the book".
The question comes from reading Samuel Groner; http://www.nanovolt.ch/resources/power_amplifiers/pdf/audio_power_amp_design_comments.pdf , chapter 3.
That's is why I thought R13 and R20 should be of same value, in order to balance the LTP input stage by equalizing base currents of Q7 and Q11.
Still I might be wrong, I have not built or simulated this, it's on my list to do.
/örjan
My way of stating my question was not really clear.I should not have said " as in the book".
The question comes from reading Samuel Groner; http://www.nanovolt.ch/resources/power_amplifiers/pdf/audio_power_amp_design_comments.pdf , chapter 3.
That's is why I thought R13 and R20 should be of same value, in order to balance the LTP input stage by equalizing base currents of Q7 and Q11.
Still I might be wrong, I have not built or simulated this, it's on my list to do.
/örjan
Don't worry too much about the details in the book regarding the BC-1. Rick and I have done a lot of refinements to the design, both in component values and circuit board implementation. Time has passed as well. Work directly with the materials and information provided with the PCBs.
Cheers,
Bob
Cheers,
Bob
Hi Bob, is this new circuit (BC-1 V2.0) going to be made available on this forum? I'm sure members here would want to design their own PCB.
Last edited by a moderator:
There is no bc-1 v2.0, all we did was change a couple of values from what was printed in the book, I detailed those changes a few posts ago.
I am not sure what you mean by a “group buy of components”, which components? the pcb set is available for purchase, when you buy the pcb set you get links to shopping carts at Mouser to purchase the components and a link to the build documentation.
Of course you are free to design your own pcb(s) if you so desire but it is a lot of work. You need to figure out the mechanical design, power supply etc. Offering a pcb set as a reference design does save you a lot of development time since the mechanics have been done and the design has been tested and verified.
I am not sure what you mean by a “group buy of components”, which components? the pcb set is available for purchase, when you buy the pcb set you get links to shopping carts at Mouser to purchase the components and a link to the build documentation.
Of course you are free to design your own pcb(s) if you so desire but it is a lot of work. You need to figure out the mechanical design, power supply etc. Offering a pcb set as a reference design does save you a lot of development time since the mechanics have been done and the design has been tested and verified.
Last edited:
Hi,
For me the mechanics is the hardest part ( I hope ).
So a group buy of a predrilled an tapped enclose might be a good idea. Problem might be to agree on what contacts to use.
I like balanced inputs which the bc1 doesn't have. And I like the neutrics speacon connectors. But that's me...
To start with I will use a Lundahl transformer to get balansed input, while planning for a more permanent solution.
/örjan
For me the mechanics is the hardest part ( I hope ).
So a group buy of a predrilled an tapped enclose might be a good idea. Problem might be to agree on what contacts to use.
I like balanced inputs which the bc1 doesn't have. And I like the neutrics speacon connectors. But that's me...
To start with I will use a Lundahl transformer to get balansed input, while planning for a more permanent solution.
/örjan
Hi,
If you run a new batch of pcb's, perhaps you can add holders for european size fuses.
/örjan
If you run a new batch of pcb's, perhaps you can add holders for european size fuses.
/örjan
Member zoji6645 designed a balanced input pcb for his build. Imo using a transformer or adding a balanced to single ended pcb would degrade performance somewhat or maybe better put compare the advantages for vs against, all design trade offs depending on your particular situation
Changing the speaker jacks from dual binding post is up to you. I looked at speakon connectors and did not see any advantage, actually I thought them to be a disadvantage for a number of reasons. But if you have cables already made using them it does make sense to want to change or add them to the back panel.
On our builds we bought the chassis and machined them ourselves.
There is very little interest in building this design so I am not going to do any revisions esp for a common fuse that is readily available from the linked supplier being Mouser.
But if you do your own design you are free to choose your favourite components just like I did.
Changing the speaker jacks from dual binding post is up to you. I looked at speakon connectors and did not see any advantage, actually I thought them to be a disadvantage for a number of reasons. But if you have cables already made using them it does make sense to want to change or add them to the back panel.
On our builds we bought the chassis and machined them ourselves.
There is very little interest in building this design so I am not going to do any revisions esp for a common fuse that is readily available from the linked supplier being Mouser.
But if you do your own design you are free to choose your favourite components just like I did.
Last edited:
Hi Richard.
As I said " if you run a new batch" I tried to imply, if there is more interest. But it was just a suggestion.
And I bought the recommended chassis and started machining it, that's how I know it can be hard at least for me.
/örjan
As I said " if you run a new batch" I tried to imply, if there is more interest. But it was just a suggestion.
And I bought the recommended chassis and started machining it, that's how I know it can be hard at least for me.
/örjan
Running a new batch is different than changing the design but I get your point that a 5x20mm line fuse is preferred in Europe. Actually I used 5x20 mm fuses on the PS pcb because they take less room. So I am not consistent with my fuse size selection.
I understand it’s a bit of a challenge to do the machining, the back panel was difficult for me as well. Might be one of the reasons why more do not build their own. Member zoji6645 said he had his done at a machine shop and designed a cad file based on my hand done mech drawing.
Good luck
I understand it’s a bit of a challenge to do the machining, the back panel was difficult for me as well. Might be one of the reasons why more do not build their own. Member zoji6645 said he had his done at a machine shop and designed a cad file based on my hand done mech drawing.
Good luck
For reference my reasons for preferring SpeakOn include:
1) Can be plugged in easily behind equipment, blind even, in a second or so.
2) No chance of accidental short-circuit from loose strands compared to binding post
3) Output voltages cannot be touched (many amps output more than 60V, which comes under different regulations for safety reasons)
4) Can't accidentally reverse polarity
5) heavy current handling, 40A.
6) definite locking connector, won't pull out or be a loose connection.
7) Stereo speakers can be on one connector if you want.
Means you can plug and play with ease
As always, thanks for input Mark, you make many good points, I am so used to using binding post. Using speakon has many advantages vs my disadvantages which amount to having to make up new cables, a bit more cost involved, maybe the machining esp if doing it by hand. I also bought a used GreenLee chassis punch which made it much easier. Its a big back panel so easy enough to use either one type or both.
I looked at Neutrik speakON again, definitely doable if you so desire. Cheaper than I originally thought.
A few issues to decide, would you want one or two of them?, a 4P is one less hole to machine for a pair or you have option with two holes to use two 2P or 4P
Male or female contacts on the chassis?
Silver plate is low Z connection but also tarnishes as well, same issue as the relay contacts.
A few issues to decide, would you want one or two of them?, a 4P is one less hole to machine for a pair or you have option with two holes to use two 2P or 4P
Male or female contacts on the chassis?
Silver plate is low Z connection but also tarnishes as well, same issue as the relay contacts.
With respect to SpeakOn silver contacts, I understand that silver oxidation is nonetheless conductive. What I have never seen is info as to whether silver oxidation has markedly different conductivity as compared to non-corroded silver base metal.
I think Neutrik told me that contacts are self-wiping, in any event. If not, I can see why binding posts are preferred as the contact areas can be readily accessed for cleaning and addition of anti-corrosion treatments like Cramolin and conductivity enhancers like Silclear from Mapleshade Audio (I use both on RCAs, speaker pins and spades). The housed contacts of SpeakOn are great for safety and phasing integrity, but not good for treatment of the contacts. I guess, however, that one can always untwist and retwist the SpeakOn once a month to clean the contacts if they are self-wiping. That is pretty easy.
I think Neutrik told me that contacts are self-wiping, in any event. If not, I can see why binding posts are preferred as the contact areas can be readily accessed for cleaning and addition of anti-corrosion treatments like Cramolin and conductivity enhancers like Silclear from Mapleshade Audio (I use both on RCAs, speaker pins and spades). The housed contacts of SpeakOn are great for safety and phasing integrity, but not good for treatment of the contacts. I guess, however, that one can always untwist and retwist the SpeakOn once a month to clean the contacts if they are self-wiping. That is pretty easy.
One additional thought: I have Vandersteen speakers which are set up to be bi-wired. So, a 4-pole SpeakOn on each side makes sense for my situation.