Hi All
After the parts bin scramble I've found loads of 337.
but in two HFE ranges.
so 337-25 and 337-40.
any preference on the best ones to use or does it matter?
Use the BC337-40.
Colin Wonfor's SECA amp build
- Thread starter Marra
- Start date
Use the BC337-40.
Thanks Colin
even more scary is that the BC337 are all measured for VBE and HFE so matching across the boards will be a breeze.
Not needed but the work is already done so why not.
Mr OCD strikes again
Thanks also for the soft start wiring schematic.
The board had me scratching my head a little.
Makes much more sense now.
I was wondering why the relay driver part of the PSU board was left unpopulated but now all is clear.
Thanks Colin
even more scary is that the BC337 are all measured for VBE and HFE so matching across the boards will be a breeze.
Not needed but the work is already done so why not.
Mr OCD strikes again
Thanks also for the soft start wiring schematic.
The board had me scratching my head a little.
Makes much more sense now.
I was wondering why the relay driver part of the PSU board was left unpopulated but now all is clear.
Good I am glad you got I am still confused, it has been a crap week again, I do hate hospitals, but might just set up a tent there soon. It would be cheaper than Taxi's every time. Sorry to hear about you frequent hospital visits and hope things ease a little soon.
The good old parts bin has supplied some of what is needed for the SECA board.
I'll mop up the rest with my birthday war chest
I'm planning on reverting back to type and build two Mono's. Heatsinks which I have already nailed to chopping boards.
I'll then hope to have the ''basic'' SECA up and running for a listen and see how the heat thing works out in practice.
Then I'll add the PSU and soft start modules just to hear the difference if any that they make.
I'll be ordering another soft start board at some point for the mono build if that's OK.
Not strictly needed for a mono build but they do so much more than the soft start name suggests.
The good old parts bin has supplied some of what is needed for the SECA board.
I'll mop up the rest with my birthday war chest
I'm planning on reverting back to type and build two Mono's. Heatsinks which I have already nailed to chopping boards.
I'll then hope to have the ''basic'' SECA up and running for a listen and see how the heat thing works out in practice.
Then I'll add the PSU and soft start modules just to hear the difference if any that they make.
I'll be ordering another soft start board at some point for the mono build if that's OK.
Not strictly needed for a mono build but they do so much more than the soft start name suggests.
This amp is really starting to sing now that I am using my BA3 pre in place of the TVC
Well done can we see some pic please
This amp is really starting to sing now that I am using my BA3 pre in place of the TVC
interesting
Can you post a link to the BA3?
From memory that's a high gain pre.
Yank
Bulbous Also Tapered
interesting
Can you post a link to the BA3?
From memory that's a high gain pre.
http://www.diyaudio.com/forums/pass-labs/234641-ba-3-preamp.html
http://www.diyaudio.com/forums/pass-labs/258022-ba-3-preamp-build-guide.html
http://www.diyaudio.com/forums/pass-labs/195303-burning-amp-ba-3-a.html
thanks for the link guys.
another question.
I've noticed that the required transformer secondary voltage is listed as 15-18v on the above schematic.
is their any advantage to be had from running 18V trafo's.
I've had another look at Colin's build (further back in the thread) and it looks like he has 15V transformers with 25v tank caps (unless I've read that wrong as 18v with 25V caps seems close to the bone).
I'm intending to build the SECA without the PSU to begin with so 15V would save a little heat with that config.
But if 18V secondaries would be better then I'll go with that.
getting near to ordering sooooo
any opinions welcome.
another question.
I've noticed that the required transformer secondary voltage is listed as 15-18v on the above schematic.
is their any advantage to be had from running 18V trafo's.
I've had another look at Colin's build (further back in the thread) and it looks like he has 15V transformers with 25v tank caps (unless I've read that wrong as 18v with 25V caps seems close to the bone).
I'm intending to build the SECA without the PSU to begin with so 15V would save a little heat with that config.
But if 18V secondaries would be better then I'll go with that.
getting near to ordering sooooo
any opinions welcome.
cj66
pfm Member
Hi Shaun,
Remember we put the biggest TXs into the RG 15w ClassA builds, I've since upped the old SCHA as well, definitely better in those cases.
The heat sinks are big mammas on this design so you should be good. I'm thinking of playing in the new year but I'll be after more watts than 15.
Bit of a Pepperami with the volume control!
Remember we put the biggest TXs into the RG 15w ClassA builds, I've since upped the old SCHA as well, definitely better in those cases.
The heat sinks are big mammas on this design so you should be good. I'm thinking of playing in the new year but I'll be after more watts than 15.
Bit of a Pepperami with the volume control!
Hi Shaun as you've noted I have used a transformer with 18V secondaries which is giving +- 22VDC with both channels running of the same supply. BIG heatsinks. Set at 1.7A of current my sinks are sitting at 40C even after several hours of use..
If the addition of the tracking supply has the same effect as LesW's excellent VBE boards has on the sound quality of the NCC's then there will be two truly excellent amps in our collections
If the addition of the tracking supply has the same effect as LesW's excellent VBE boards has on the sound quality of the NCC's then there will be two truly excellent amps in our collections
Hi Chris
Nice to hear from you.
Yes the bigget trafos sure worked.
After a few more than 15W, wash your mouth out
Seriously if youd like more power.
The Voyagers are superb IMHO so drop me a PM if youd like to have a chat on this further.
Work well with what you have also.
Nice to hear from you.
Yes the bigget trafos sure worked.
After a few more than 15W, wash your mouth out
Seriously if youd like more power.
The Voyagers are superb IMHO so drop me a PM if youd like to have a chat on this further.
Work well with what you have also.
Hi Shaun as you've noted I have used a transformer with 18V secondaries BIG heatsinks. Set at 1.7A of current my sinks are sitting at 40C even after several hours of use..
If the addition of the tracking supply has the same effect as LesW's excellent VBE boards has on the sound quality of the NCC's then there will be two truly excellent amps in our collections
Hi Keith
it's going to be fun finding out and that's for sure.
we can compare notes on that as we go.
BTW the 33000uf 35v caps listed in the boom are out of production but I've managed to find some on flea bay.
Could be worth checking for some alternatives as the Farnell replacements are a little pricy IMHO.
18V it is then.
Hi Keith
it's going to be fun finding out and that's for sure.
we can compare notes on that as we go.
BTW the 33000uf 35v caps listed in the boom are out of production but I've managed to find some on flea bay.
Could be worth checking for some alternatives as the Farnell replacements are a little pricy IMHO.
18V it is then.
Check CPC
http://cpc.farnell.com/webapp/wcs/stores/servlet/Search?catalogId=15002&langId=69&storeId=10180&categoryId=700000011511&st=22000uf&pageSize=25&showResults=true&pf=110151911,110189644
