(AK) Class A HA PCB and parts Group Buy

[Deleted]

Hi Martin

good work locating the SF 14's they should work really nicely and if you can't find 12's do remember to keep two back for the HA/PRE.

great stuff

keep us posted on your progress.

take care

[pingu]

Hi Shaun,

Thanks I will remember. If you want some let me know.
If you want a shed load I can add it to my order and post on to you so you can avoid postage on the one item.

Bits on their way end of the week I hope, so finish the JLH REs and the PSU then just the HAs to get sorted, when the GB goes ahead.

Freind has just got a BT928 HA that he wants me to mod a la Mike's notes from a while ago.
So another job in the list to get round to.
Martin

[Deleted]

Hi Martin

''Freind has just got a BT928 HA that he wants me to mod a la Mike's notes from a while ago.
So another job in the list to get round to.''

All good and nice to have something to do while waiting

take care

[floriangerard51]

it's now 6months from where i was modding my BRAVO V2 amp and i got lots of fun with it. I now wants more.

I'm now decided to go with a SS amp to change my point of view...And it will also drive my HD650.

I was reading a lot the DIY part of the forum but i can't really sum up the thread concerning the SC HA 15W amp. I'm quite confused. It will be better than the panda amp for my HD650? i saw two thread about SC 15W amp what it the good one for headphone? And is there any way to sum up the total need of PCBs?

I think there are 2 PCB for powering (Each one for each channel right?), also 2 JLH PCB ? and the 2 PCB for the amp part right?

Where can i buy the PCBs ? Plus is there any BOM for parts? I have full acces to RS components and will buy every thing from there.

Thanks

[gommer]

Hello Florian,

You will be able to get everything you need right here, except for the ripple eater boards, those appear from time to time, both here and on DIY-audio.
I'm organizing the group buy for all necessary parts, including components (without resistors though). You can find the first BOM for class A HA somewhere in this thread. More to follow.

Cheers, Marc

[floriangerard51]

hello

Thanks for the reply! I will try to read this full post. Do you have the link for the original thread concerning this amp?

Ok then i'll be ok to buy all the necessary PCBs for this amp. Do you have the list of PCBs needed??? How much will it cost?

I don't see any news from Frans (solderdude) and also his mail give me that he doesn't exist anymore. Do you know what's happening?

[floriangerard51]

HELLO guys,

What do you think of this kind of PCB for the primary AC/DC conversion???

Based on 2 LT1083CP ! 7amps each ones...

www.ebay.com/itm/Regulated-power-supply-PCB-for-JLH-amplifiers-DIY-/260584386195?pt=US_Home_Audio_Amplifiers_Preamps&hash=item3cac0a2e93

[Will]

Hi Florian

The thread that deals with the headphone amp is this one SC Class A, the other thread refers to the loudspeaker version.

All the info is in that thread, and Marc (gommer) will be able to advise on cost. etc as he is running the GB.

The PSU pcb's, if they are what they think they are, look like they are good to supply the speaker amp, let alone the HA version. Marc is offering my dual pcb as part of the GB, which is more than enough for the HA.

[pingu]

Mar 16, 2013 20:45:28 GMT floriangerard51 said:

HELLO guys,

What do you think of this kind of PCB for the primary AC/DC conversion???

Based on 2 LT1083CP ! 7amps each ones...

www.ebay.com/itm/Regulated-power-supply-PCB-for-JLH-amplifiers-DIY-/260584386195?pt=US_Home_Audio_Amplifiers_Preamps&hash=item3cac0a2e93

Hi Florian,

I looked at that PSU board too, it seems OK as Will said BUT the voltage regs are in the middle of the board so difficult (but not impossibel) to use board mounted heatsinks. The board has loads of power potential and is ample for the HA and then some.

Jaycar have a very reasonable kit that I was told (thanks to Shaun for his help) would work with the HA and it has plenty enough current too. On this link,

www.jaycar.co.uk/productView.asp?ID=KC5501&form=CAT2&SUBCATID=965#11.

If you buy a quantity they come cheaper and post free works out something like buy 3 get 2 free......always handy to have a PSU or two spare, or sell/pass them on on this site

Other wise add your name to the GB for the amp / psu / bits and bobs. Marc (Gomer) is working hard on organising this (thanks very much Marc)

Martin

[pingu]

Hi Florian,
If you look closely at the first pix by Leo in the thread Wills mentioned in his post I think you will see at the top the PSU and it looks Like one of the Jaycar kits or a variation on one of them.
Maybe Leo can enlighten us
Martin
PS didn't we do well yesterday

[floriangerard51]

Hi guys

Thanks for the replies. I'll check the good thread (77pages ;-) to have more info about this amp.

But i'm ok for the GB of the PCBs. For the parts it will depends on the total cost of the package...As i said i have illimited acces to RS and so i doesn't cost me one euro so better for me to buy from RS. But as you said also it will be good for the rare parts like the LS or the paired parts for example.

I just finished today a portable CMoy amp buy JDSLabs for 5$ pcb thats quite good even for my HD650. Supply by 4 9V 250mah batteries...

Can you Marc please add my name for all the PCBs and X2 as i could make 2 amps one for me and other for my friend.

thanks!

[gommer]

Hi Florian, your request is noted. When I find the time to update the participants list, I'll add you. I'll also do a price estimate for all parts.

Cheers, Marc

[floriangerard51]

ok thanks !
Price could be large estimation ;-) 0-100€ 100-200€....Just to calculate total cost.

[pingu]

Mar 17, 2013 22:14:53 GMT gommer said:

Hi Florian, your request is noted. When I find the time to update the participants list, I'll add you. I'll also do a price estimate for all parts.

Cheers, Marc

Hi Marc would appreciate an estimate too ...... no rush at all just curious.
When you have time will be fine and I am aware it will be only a very rough estimate so no worries.
All the best
Martin

[Deleted]

Please tentatively count me in on the GB, subject to cost and anticipated schedule.
Dave.

[Deleted]

Mar 21, 2013 10:19:30 GMT @davek said:

Please tentatively count me in on the GB, subject to cost and anticipated schedule.
Dave.

Dave
The preamp version uses the same PCBs, and 2 external toroidal transformers in a fairly small case as the HA.
It uses additional input and output switching compared with the HA version, and can also be fitted with a headphone jack.
In the preamp shown in the photo , I have left room for a headphone jack and headphone/preamp selector switch.
As I have a separate HA for my PC, I didn't feel the need for a headphone jack in the preamp.
The small PCB at the rear is a delay PCB which has provision for a headphone output.
The PCB could be replaced by a front panel rotary switch to choose between headphones and preamplifier output.
It can be used as a standalone headphone amplifier without switching on the 15W Class A
Regards
Alex

[Deleted]

Mar 21, 2013 10:19:30 GMT @davek said:

Please tentatively count me in on the GB, subject to cost and anticipated schedule.
Dave.

Hi Dave

good chioce

take care

[gommer]

Hi Dave, also noted.

@ All, I've had some terrible past weeks at work and it'll only end next Tuesday (in theory, aka 'I hope'). So, please bear with me.

Marc

[Deleted]

When the Class A HA is also used as a preamp,, because the 15W Class A already has a delay circuit at switch on, it may be worthwhile fitting a 2 position 6 pole rotary switch instead, to switch between headphones and preamplifier. When used as a preamplifier, a 100 ohms series output resistor appears to be about optimum.
However, some headphones will work best with different output resistor values. In that case, the series output resistors on the PCB could be replaced by links, and different resistor values could be fitted on the rotary switch for headphone operation.
I haven't tried that, but it should be fairly easy to do with a 2 position 6 pole rotary switch.
Regards
Alex

P.S.
Someone like Marc could probably design something like that in his sleep even. .

[FritzS]

what parts I missing yet:

terminals with 4 - 5 mm long pins - only for the both amp PCB's

good socket pins for the dual BJT's (T2, T3) - I have seen some use them

SF11 or SF12 Schottky diodes (D1)

additional heatsinks for the Jaycar PSU (the same as enclosed in kit).

[Deleted]

good socket pins for the dual BJT's (T2, T3) - I have seen some use them

I do not recommend their use with this PCB. The only person who used them in RG got into all kinds of trouble.
Alex

[pingu]

Hi Alex,
I have now copleted 90% of the PSU boards (Will's Dual Reg) that Shaun kindly sent me (thanks again Shuan) but I am about to order the caps for them and I was wondering should I use "audio grade", low ESR types or just whats "in stock" these are the caps C2 to C6.
Also C1 the small 470Nf 100V cap, as I am using fast schotsky doides is it needed?
The PSUs will be used before the ripple eaters in the SC AH projcet and when some PSUs from the GB arrive they will be used to power a +/- 12v Richard Brice HA from an old HFW project.
I have used the SF 14 diodes as no 12's were around ATM and some thin film 0.6wat resists from RS (good pice).
It seems you have the Knowledge so may I pls pick your brains?
Martin

[Deleted]

Apr 1, 2013 16:43:30 GMT pingu said:

Hi Alex,
I have now copleted 90% of the PSU boards (Will's Dual Reg) that Shaun kindly sent me (thanks again Shuan) but I am about to order the caps for them and I was wondering should I use "audio grade", low ESR types or just whats "in stock" these are the caps C2 to C6.
Also C1 the small 470Nf 100V cap, as I am using fast schotsky doides is it needed?
The PSUs will be used before the ripple eaters in the SC AH projcet and when some PSUs from the GB arrive they will be used to power a +/- 12v Richard Brice HA from an old HFW project.
I have used the SF 14 diodes as no 12's were around ATM and some thin film 0.6wat resists from RS (good pice).
It seems you have the Knowledge so may I pls pick your brains?
Martin

Hi Martin
Do NOT use low ESR electrolytic capacitors in the PSU PCBs. Normally available ordinary types will be fine.
IIRC, I used Panasonic FC in mine because they were fatter, but not as tall as others, and fitted in a 1U rack case.
The 470nF is not needed.
Regards
Alex

[pingu]

Thanks Alex,
help much appreciated and that has saved me some pennies too.
I will crack on and get the caps now.

I am working without a schematic of Will's PSU (I think it is the one for the SC HA with the 337/317 regs on it) and have looked on here but can not seem to find one. I am sure I have missed it, would you know where one is?
Thanks again
martin

[Deleted]

Apr 2, 2013 9:02:27 GMT pingu said:

Thanks Alex,
help much appreciated and that has saved me some pennies too.
I will crack on and get the caps now.

I am working without a schematic of Will's PSU (I think it is the one for the SC HA with the 337/317 regs on it) and have looked on here but can not seem to find one. I am sure I have missed it, would you know where one is?
Thanks again
martin

Martin
I am unable to locate a copy of Will's schematic. However, you should be able to work out most of the components from the attached.
The main electros are 2,200uF 25V, The "adjust" capacitor is 10uF 35V, and the output capacitors are likely to be 100uF 35V.
One of the others who has used these PCBs should be able to tell you the values of the resistors, and the trimpots used for the LM317 and LM337.
D5,6.7 and 8 can be 1N4002 or 1N4004.
Regards
Alex
P.S.
See Shaun's post for other alternatives and the resistor values.

rockgrotto.proboards.com/thread/8894/class-pcb-parts-group-buy?page=6