(AK) classA HA/Preamplifier.

[XTRProf]

Hi Will,

Wow, luckily I drop in here or I will have missed it. Great work, Will! One set (2 PCBs) for me until you have another better revision on a single board. I've been wanting to build Alex's Class A headphone amp but just didn't have the time. Now you have set me in motion. Btw, just to confirm, this is Alex's Class A Headphone amp, right? Save me from having to read the whole thread.

Thanks.



Chong

[FritzS]

The pcb layout is pretty much done, so barring any mishaps we should be ready to buy them.The PCB's will be the same quality as the recent JLH GB, 3mm thick, 70uM copper traces and a pretty colour if required Size is 120mm x 90mm per pcb.You'll need two pcb's for a stereo pair. Based on 10 pcb sets, The approximate price for a set is €15 (£13 or AU$21) Delivery and Paypal to go on that. The more pcb's are ordered the cheaper they become for everyone, and you get them at cost price.

Hi Will,
great work!
I want a set (of two PCB's) too!
I will send you an eMail later.

[Will]

Blimey! You're all quick off the block! No problems, Gents, you are on the list!

[Will]

I also meant to say a big Thank You to Jon Clancy, for being the Ninja lib. Guru that he is, and creating the custom LS313/352 and 2 pin connector files for this PCB.

Cheers Mate

[Deleted]

Hi Will

how's it going?

I would love 2 pairs of boards thanks. no need to worry about color on my account unless it may alter the sound. (red may sound better than blue )

I'll make a donation to charity also as i thinks it worked well for the JLH. (Greyhound Rescue West England ) would be my personal choice but I'm open to suggestions on that one.

thanks Will 8-)it looks like fun and I'm looking forward to getting started.

I've found the GB at DIYAUDIO and put in for 4 of the input fets. ;D ;D so thanks for that also.
take care

[Deleted]

Nov 17, 2010 12:57:47 GMT Will said:

Blimey! You're all quick off the block! No problems, Gents, you are on the list!

Hi Will
Please include me on the list for 2 sets (4 PCBs)
I have been holding off upgrading my preamp to the metal can duals.
Guys, don't forget that you will also need 4 JLH PCBs from the current Group Buy !
Alex

[Deleted]

Hi Alex

thanks for the info re the JLH GB. I'm in for 10 of those and just waiting for it to go live. (some fore the future) i also have some Jcar psu's so it's all good to go.

Take care

[Deleted]

how do we go with the double input fets they look quite hard to source take care

Shaun
They are dual bipolar transistors in metal cans, not FETs.
This means they will be more closely matched than is usually possible with readily available FETs.
Alex

P.S.
Are you an expat Aussie ?
You remind me of a guy from Richmond, west of Sydney, with some of the phrases you use.

[Deleted]

Hi Alex

thanks for the update ;D so many new names to learn tubes are so much easier pentode :-/triode :-/pentode :-/triode oh yes and tetrode

i need to pay more attention i need to pay more attention..........

I'm in anyway

take care

[Deleted]

Yeehawwwwwwwwwwww!

Great stuff Will. 2 pairs please. (headamp first, then I feel a pre amp coming on )

Chris

[Deleted]

Nov 17, 2010 13:38:18 GMT @sandyk said:

how do we go with the double input fets they look quite hard to source take care

Shaun
They are dual bipolar transistors in metal cans, not FETs.
This means they will be more closely matched than is usually possible with readily available FETs.
Alex

P.S.
Are you an expat Aussie ?
You remind me of a guy from Richmond, west of Sydney, with some of the phrases you use.

Hi Alex

no not an ex pat but i found my London drawl and the Australian accent pretty darn close ;D. along with the sense of humor.
i took the POM jokes in good heart and secretly loved em.
i always think of where i was in Aus at what time of year. right now ten years ago i was in the Snowy Mountains avoiding the possums and getting lost in the fog.

felt like home from home to me.

sorry for the OT

take care

[jonclancy]

Nov 17, 2010 13:24:43 GMT Will said:

I also meant to say a big Thank You to Jon Clancy, for being the Ninja lib. Guru that he is, and creating the custom LS313/352 and 2 pin connector files for this PCB.

Cheers Mate

It's a pleasure, and very kind of you to say so....

I'd like two sets please. In ninja black, of course.

Cheers

Jon

[Will]

Btw, just to confirm, this is Alex's Class A Headphone amp, right?

Hi Chong,
yes this is Alex's Class A headphone amp, with all the mods. It can also be used as a pre-amp, if you wire up an input selector.

[XTRProf]

Nov 17, 2010 19:26:00 GMT Will said:

Btw, just to confirm, this is Alex's Class A Headphone amp, right?

Hi Chong,
yes this is Alex's Class A headphone amp, with all the mods. It can also be used as a pre-amp, if you wire up an input selector.

Thanks for the confirmation!

[XTRProf]

Nov 17, 2010 18:03:31 GMT jonclancy said:

I'd like two sets please. In ninja black, of course.

Cheers

Jon

Heh, heh, with your leopard or cheetah avatar pic, I wouldn't mind spotted PCBs like 101 Dalmation. Wouldn't that be wonderful for a Christmas present for all and something new to show the world what the talents and creative minds of Rockgrotto can do?

Will, I think before long there will be 100 sets GB instead of just 10.

[XTRProf]

I can't believe it .............







Link: cgi.ebay.co.uk/JHL-Class-headphone-amplifier-earphone-AMP-preamp-/110611935955?pt=UK_AudioTVElectronics_HomeAudioHiFi_Amplifiers&hash=item19c0fc32d3




Is this the same? Thanks.

[Deleted]

Nov 18, 2010 3:02:10 GMT XTRProf said:

I can't believe it .............




Link: cgi.ebay.co.uk/JHL-Class-headphone-amplifier-earphone-AMP-preamp-/110611935955?pt=UK_AudioTVElectronics_HomeAudioHiFi_Amplifiers&hash=item19c0fc32d3




Is this the same? Thanks.

Chong
It's based on a very old design by John Linsley Hood.
We have come a long way since those days!
These days it's more of nostalgia value, although it can be made to sound O.K. There is a small thread about it in RG too.
I think the lack of bids speaks volumes ?
Alex

I think he makes his money from postage charges ?

[XTRProf]

Nov 18, 2010 4:26:08 GMT @sandyk said:

Nov 18, 2010 3:02:10 GMT XTRProf said:

I can't believe it .............







Link: cgi.ebay.co.uk/JHL-Class-headphone-amplifier-earphone-AMP-preamp-/110611935955?pt=UK_AudioTVElectronics_HomeAudioHiFi_Amplifiers&hash=item19c0fc32d3




Is this the same? Thanks.

Chong
It's based on a very old design by John Linsley Hood.
We have come a long way since those days!
These days it's more of nostalgia value, although it can be made to sound O.K. There is a small thread about it in RG too.
I think the lack of bids speaks volumes ?
Alex

I think he makes his money from postage charges ?

Ha, ha, he must also include valves to entice people to buy as well since this is Mk 1.

[Will]

Will, I think before long there will be 100 sets GB instead of just 10.

That'd be nice!

I must admit to being quite chuffed with the response so far, it's made the effort put in worthwhile.

Hopefully the LS device GB will pick up as well. They are pricey, but saves loads of time buying and matching transistors. The PCB has been designed to take these LS devices directly, rather than having to twist legs like previously.

With the closely matched devices and the LTP mod, you end up with an amp which is very transparent

[XTRProf]

Nov 18, 2010 9:06:21 GMT Will said:

Will, I think before long there will be 100 sets GB instead of just 10.

That'd be nice!

I must admit to being quite chuffed with the response so far, it's made the effort put in worthwhile.

Hopefully the LS device GB will pick up as well. They are pricey, but saves loads of time buying and matching transistors. The PCB has been designed to take these LS devices directly, rather than having to twist legs like previously.

With the closely matched devices and the LTP mod, you end up with an amp which is the very transparent

Excellent! We hardly can wait to have this GB closed ............



Chong

[Will]

A couple of people have asked if this pcb can be used as a speaker amp. It could, but would not perform as well as it could do, due to shared supply lines between the power section and the front end. The power section would be supplied from a regulated supply, with the front end being fed via a JLH. (Alex, please correct if I'm wrong here)

If there is general interest in doing a loudspeaker version, including the LTP mods, then I'll look into this version, but not until next year. PCB size would be the same, so costs would be the same.

[Deleted]

Nov 18, 2010 9:35:55 GMT Will said:

A couple of people have asked if this pcb can be used as a speaker amp. It could, but would not perform as well as it could do, due to shared supply lines between the power section and the front end. The power section would be supplied from a regulated supply, with the front end being fed via a JLH. (Alex, please correct if I'm wrong here)

If there is general interest in doing a loudspeaker version, including the LTP mods, then I'll look into this version, but not until next year. PCB size would be the same, so costs would be the same.

Will
That is correct. Best results are with a separate JLH for each Channel's front end, too.
Alex

[FritzS]

hat is correct. Best results are with a separate JLH for each Channel's front end, too.

If I understand right - I could made this amp first with only one PSU including one JLH pair (for + and -) - and with good results.

If I use only one PSU but two JLH pairs (each channel have her own JLH's) - whats with the influence from the grounding path?

I know the ultimate step is to use two separate PSU path, one for each channel.

Whats the difference between a stepping attenuator and a good potentiometer (ALPS blue or black). First I will use a ALPS, later I could mod ....

PS: OT - last time I get the insight my WNA MKII sounds a bit better than my Solo .... it's a spinoff of my Q701 testing and comparing

[Deleted]

Nov 18, 2010 10:16:26 GMT FritzS said:

hat is correct. Best results are with a separate JLH for each Channel's front end, too.

If I understand right - I could made this amp first with only one PSU including one JLH pair (for + and -) - and with good results.

If I use only one PSU but two JLH pairs (each channel have her own JLH's) - whats with the influence from the grounding path?

I know the ultimate step is to use two separate PSU path, one for each channel.

Friedrich
I used a single PSU and a single JLH until recently, when I was spurred on by the further improvements that Will obtained.
I wouldn't use 2 JLHs with a single PSU PCB due to the much heavier startup current demands on a single PSU. The recommended KC5418 PSU kits (Jaycar) are only about AU$20 each.
Alex

[Will]

Whats the difference between a stepping attenuator and a good potentiometer (ALPS blue or black). First I will use a ALPS, later I could mod ....

I went from an ALPS Blue to a 'eBay' stepped attenuator, and found the sound to be that little cleaner (like looking through a window that's just been cleaned, I think I said at the time ;D)

I use a £10 ebay stepped smd in my Class A, looks similar to the one in Alex's last posted Class A HA. I think he uses a DACT in his pre-amp, which are becoming slightly more affordable, as I've seen them for around £80.

I'll be trying the LDR/Lightspeed at some point with the class A, as it's had some good reception.