Pictures of your diy Pass amplifier

[timbarnes]

My F4

Just finished over the weekend. Back to enjoying the music...

(Copy of post in the F4 thread: hope that's not breaking the rules...)

 

[carpenter]

Sweet! Are your transistors staying cool?

 

[timbarnes]

Sweet! Are your transistors staying cool?

Not as cool as I'd like: with about 205mV across the .47 ohm resistors, the heatsink is getting pretty hot: I have to be a bit determined to keep my fingers on for 5 seconds . I will do another round of adjustments now everything is wired up and I may take the bias down a fraction.

I used all the heatsink I had...

 

[CanAm Man]

Tim, also keep a close eye on those in-rush limiters (thermistors). Depending on your amps operating condition, they can run very hot--and it looks as though you have them mounted on/near wood.....

Unless you're into the aromatherapy of burnt pine, this might be a problem....

Ken

 

[Nelson Pass]

Not as cool as I'd like: with about 205mV across the .47 ohm resistors, the heatsink is getting pretty hot: I have to be a bit determined to keep my fingers on for 5 seconds

You have 6 devices so the chip temperature is not likely to get too hot.

 

[AudioSan]

one of my Aleph2 monoblocks almost done. it is up and running.
and running some how cool about 18-20C above ambient

 

[Andersonix]

Tim, also keep a close eye on those in-rush limiters (thermistors). Depending on your amps operating condition, they can run very hot--and it looks as though you have them mounted on/near wood.....

Unless you're into the aromatherapy of burnt pine, this might be a problem....

Ken

I agree that this is very naughty!

 

[carpenter]

one of my Aleph2 monoblocks almost done. it is up and running.
and running some how cool about 18-20C above ambient

Very, very nice. Those large heat sinks are performing rather well, it seems.

 

[AudioSan]

thanks yes they are. it takes well over 2 hours to warm up

 

[timbarnes]

Tim, also keep a close eye on those in-rush limiters (thermistors). Depending on your amps operating condition, they can run very hot--and it looks as though you have them mounted on/near wood.....

Unless you're into the aromatherapy of burnt pine, this might be a problem....

Ken

Thanks: there's no sign of heat on the top: I didn't want to put my finger on them seeing as they are part of the power supply...

 

[digits]

Now that I look at it, those sinks don't seem connected to ground.... BAD mmmmkay, all exposed conductive surfaces should be grounded.

 

[timbarnes]

Now that I look at it, those sinks don't seem connected to ground.... BAD mmmmkay, all exposed conductive surfaces should be grounded.

Thanks for your concern. Actually I have run a grounding wire down through the bottom of the case and out to all the metalwork. Ohmmeter says it's all grounded.

Tim

 

[digits]

Awesome, then you can touch it

 

[BigE]

150 mU rail
CRCLRC + same small ones as Papa said

100 mU in the power suply

The 2 mono blocks have their own banks 50 mU rail (total of 40 10 mU caps)

At present I may ad another 50 mU rail if I go By amp or ballanced so each board got its own

And 36mU on the mains DC filter.

May I ask what you used for a soft-start circuit?

 

[Bksabath]

BigE
shure you can.
Simple transistor/relay timer.

once power up capacitor charges and trip a transistor which operate a relay that by pass the NTC

One day I will get it tidy and then post SCH for all.

Same pictures and more on my My F5 tread.

PIC Just a teaser in the corner the Aux suply and controll circuit.
In the back ground the 12mU caps for DC filter

 

[Bksabath]

Actualy found drawing of surmentioned circuit

http://www.diyaudio.com/forums/attachments/pass-labs/224321d1306339526-my-f5-new-controll-sch.doc

 

[GeeVee]

Pass Aleph P1.7 Preamp

Hi all

I would like to share my latest creation, My just completed Pass Aleph P1.7

I was completed this afternoon, and has been running all day with background music

The matching Pass X-Ono, was completed some time ago. (see Post 262 and 263) of this thread.

Now to finish off my 1.2 power amplifiers. Quite a bit of work still required.

Thanks
George

 

[blistard]

@GeeVee,

congratulations on this excellent piece of work. This looks really professional. Wish I had so much craftsmanship.

 

[jacco vermeulen]

Nostalgic look, sorta mix of a Threshold FET-Two MKI and a Spectral DMC preamp.

 

[GeeVee]

Pass Aleph P1.7 Preamp

Hi Blistard and Jacco

Thanks for your kind words. You are correct in the Spectral look. That was exactly what I was trying to achieve.
The only thing remaining is to change the knobs on the x-ono, as shown in post 262 and 263 to match.

I would like to share how I made the front panell.

The case is an off the shelf unit from the VT4C shop in Hong Kong.

The front is a 2 part affair, with a removable sub panell.

I drew up the front lettering in AutoCad (could use any other package for that matter), and printed them on overhead transperency film.

I then got 2mm thick clear acrylic cut to size for me, and then sandwiched the lot together. There are fastening screws from the rear.

It gives the front a really nice depth

Regards

George.