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RobsterD
04-05-2012, 22:15
Thought I'd try a SIT amp project,lots of info on DIY Audio forum under the Nelson Pass bit.
Finished them tonight in a prototype form driving some AER MD3's and the big Parasound A21 driving the bass cabs,sounding very sweet,anyone after a nice AN 2A3 amp ;)

http://i886.photobucket.com/albums/ac68/RobsterD/CIMG0532.jpg
Puffin
05-05-2012, 05:48
Rob, Is this configured in the same way as the De-Lite?

I tried to build a De-Lite. For some inexplicable reason (given such a simple circuit) it did not work. I keep meaning to have another crack at it.

Rob.
Marco
05-05-2012, 07:17
Wow - that's what you call valves!! What kind are those, Rob?

Marco.
Mike
05-05-2012, 08:05
Light bulbs! :lol:
Marco
05-05-2012, 08:19
That's exactly what they look like!!

Marco.
Ali Tait
05-05-2012, 08:41
That's what they are dude. :eek:
Reid Malenfant
05-05-2012, 11:06
Yes, light bulbs used as load resistors :)
Mike
05-05-2012, 11:15
Marco, it's a solid state amp! :ner:
Marco
05-05-2012, 14:05
Lol - soz, ah didnae know... :doh:

First time I've seen that! :)

Marco.
RobsterD
05-05-2012, 15:17
Rob, Is this configured in the same way as the De-Lite?

I tried to build a De-Lite. For some inexplicable reason (given such a simple circuit) it did not work. I keep meaning to have another crack at it.

Rob.

yep I beleive it is,but using the 2SK82 instead,surprisingly my effort worked first time,have a digital meter on the fronts to dial in that sweetspot.

Hey Marco the bulbs are branded Sylvania :)
camtwister
10-05-2012, 15:15
For the spiritual benefit of viewers intrigued by 300W light bulbs, sweet spot meters and static induction, here's a very well written and entertaining article by Michael Rothacher, hosted on the diyAudio site:

http://www.diyaudio.com/forums/diyaudio-com-articles/200460-l-amp-simple-sit-amp-part-1-a.html

Courtesy of Nelson Pass himself, scoot here for beguilement over the De-Lite amplifier:

http://www.firstwatt.com/pdf/art_delite.pdf

"Keep your bias high and your feedback low" compradres.
RobsterD
18-05-2012, 22:43
Mike has been a great help.
just trying some foo caps Looking at getting rid of the bulbs,will be trying a 1:1 transformer or some vishay thick film resistors but at £30 a pop dunno,also the CRC PSU will be going CLC

http://i886.photobucket.com/albums/ac68/RobsterD/CIMG0545.jpgQ


http://i886.photobucket.com/albums/ac68/RobsterD/CIMG0548.jpg
jandl100
21-05-2012, 07:50
How are you finding the Parasound A21 power amp, Rob?

I love mine to bits - it seems a perfect match for my MBL speakers. It's not too far off my first anniversary with the A21, now! :eek:
RobsterD
23-05-2012, 16:36
How are you finding the Parasound A21 power amp, Rob?

I love mine to bits - it seems a perfect match for my MBL speakers. It's not too far off my first anniversary with the A21, now! :eek:

Hi Jerry its a very nice amp,I've always had a softspot for Parasound had a long list of the HCA range couple of 1500's bridged was cool still using a 1205A for surround duties.

not sure if I'm taxing the A21,just using it to drive my 15" bass bins up to 220Hz.
jandl100
23-05-2012, 19:39
OMG - what a waste! :doh: :lol:
Reid Malenfant
23-05-2012, 19:49
OMG - what a waste! :doh: :lol:
Damn right, keep the MC² 450 for things like that & use the A21 for stereo duties :D
RobsterD
30-06-2012, 22:30
OK OK ,got the picture :)
A21 replaced by a serviced Crown DC300A
Also the power supply has been changed to a CLC from CRC on the SIT's
Hear from the DIY Audio forum Paul H has been asked to look at a regulated PSU for the amp,should be interesting
Mine tricked out with Kondo SPc power cables,SPc speaker cable and AN Vx interconnect
Some fans installed to bring down the temp just replaced with some 1200 rpm silent fans
The SIT is a funny beast,has a sweet spot dependent on speaker load.

http://i886.photobucket.com/albums/ac68/RobsterD/CIMG0842.jpg
Reid Malenfant
02-07-2012, 19:42
Some fans installed to bring down the temp just replaced with some 1200 rpm silent fans
The SIT is a funny beast,has a sweet spot dependent on speaker load.

http://i886.photobucket.com/albums/ac68/RobsterD/CIMG0842.jpg
Well for starters the heatsinks don't have the fins vertical, so they won't be anywhere near as efficient at getting rid of heat... Think of a chimney & how it draws air upwards, vertical fins have the same kind of effect ;)

I haven't seen the circuit but I'd lay a bet that there is no overall feedback what so ever & it has a high output impedance, so yes, it'll be very dependent on the speaker load :eyebrows:

No idea why the designer didn't substitute the bulbs for a choke as it'd be far more efficient, price maybe & ease of assembly as well as that glowing bottle effect :D
slate
07-07-2012, 11:46
I always get nervous when my amps starts to glow.

Hmm didn't the EU ban the use of big bulbs
RobbieGong
07-07-2012, 13:48
I always get nervous when my amps starts to glow.

Hmm didn't the EU ban the use of big bulbs

Would be the least of my worries - Talk about exposed and vulnerable !:stalks: :eek:
RobsterD
08-07-2012, 00:23
Well for starters the heatsinks don't have the fins vertical, so they won't be anywhere near as efficient at getting rid of heat... Think of a chimney & how it draws air upwards, vertical fins have the same kind of effect ;)

I have vertical and horizontal fins ;)

To Robbiegong and slate

They're in prototype form for testing and easy component changes,the bulbs will at some point be going,replaced by some thick film resistors,so please don't report me to the EU for running banned bulbs :)
RobsterD
22-06-2013, 20:09
Finished amps
http://i886.photobucket.com/albums/ac68/RobsterD/CIMG1210_zpsc4ce8e80.jpg
http://i886.photobucket.com/albums/ac68/RobsterD/CIMG1214_zps02b44f17.jpg
RobsterD
06-02-2015, 20:43
Updated pic - couple of tapped horns and a Lenco PTP turntable added,
MC2 T1000 powering the subs,BD Design BD30 chip amp on the bass drivers and the SIT's on the Voxativ Field Coils

http://i886.photobucket.com/albums/ac68/RobsterD/CIMG1901_zps38c96c67.jpg (http://s886.photobucket.com/user/RobsterD/media/CIMG1901_zps38c96c67.jpg.html)
walpurgis
06-02-2015, 20:51
That's certainly a funky looking and imaginatively designed system. I really like it, bet it sounds most impressive.
Si74
06-02-2015, 20:55
Looks brilliant Rob, is that spalted maple facing the amps?
Table & amps look anything but d.i.y. , well impressive looking.
RobsterD
06-02-2015, 21:08
cheers ,
The amp fronts are spalted beech - running out of things to do DIY
Doing the Lenco 2 speed controller at the mo in black valchromat - mock up of dials etc ,hope to get speedytsteve to get some nice bright ally knobs done soon....

http://i886.photobucket.com/albums/ac68/RobsterD/CIMG1895_zpse1f9e3b5.jpg
Ali Tait
06-02-2015, 21:20
Very nice!
RobsterD
20-02-2015, 00:15
some field coil porn

http://i886.photobucket.com/albums/ac68/RobsterD/CIMG0635_zps8a0d5a39.jpg

and if you like big caps

http://i886.photobucket.com/albums/ac68/RobsterD/CIMG1242_zps71798a32.jpg
http://i886.photobucket.com/albums/ac68/RobsterD/CIMG1237_zps2d217813.jpg
agk
20-02-2015, 17:00
Just gorgeous.
Idlewithnodrive
20-02-2015, 17:17
Absolutely bonkers, the whole rig.

Love it :thumbsup:
Riislingen
20-02-2015, 17:32
Love it !

It looks smashing across the board.
Sovereign
20-02-2015, 19:03
What are the amps rob?
Ali Tait
20-02-2015, 19:19
Mundorf caps?
RobsterD
05-03-2015, 22:45
amps are DIY SITs and the caps are these
http://www.hificollective.co.uk/components/mundorf_mlytic_hcplus.html

stacked Lenco platters,arm lead from J7 for the FR24 and turned ebony arm riser from Steve @ Magna

http://i886.photobucket.com/albums/ac68/RobsterD/CIMG1991_zps4anxvmaq.jpg
Marco
05-03-2015, 23:52
Very nice indeed, Rob. What’s the cartridge? :)

Marco.
RobsterD
06-03-2015, 00:30
Well its an AT OC9 ML2 in to an early EAR 834P and thats when it gets a bit unorthodox connects to a Trinnov ST2 so its all in the digital domain upsampled to 96K - sounds better/comparable to AIFF rips from my MacMini-Amarra rig through the same Trinnov DAC.
RobsterD
04-04-2015, 19:25
Well thats the turntable completed ,just finished the speed controller.

http://i886.photobucket.com/albums/ac68/RobsterD/IMG_05001_zpsjelfotzt.jpg
struth
04-04-2015, 21:49
Very smart Rob...VERY smart...:eek:
Firebottle
05-04-2015, 06:02
That is a piece of art, never mind kit :drool:
Spectral Morn
05-04-2015, 09:19
Well thats the turntable completed ,just finished the speed controller.

http://i886.photobucket.com/albums/ac68/RobsterD/IMG_05001_zpsjelfotzt.jpg

Wow !


Regards Neil
ReggieB
05-04-2015, 09:30
That is a piece of art, never mind kit :drool:

Agree with that!
Gordon Steadman
05-04-2015, 09:46
That is a piece of art, never mind kit :drool:

Absolutely. Ronnie just asked my why I would like to copy it for my Dual. "Just because I could and it looks wonderful" Practical woman my wife. The idea of record players as art doesn't really do it for her, she just wants them to sound great. WAF doesn't apply in our household its more HAF.
RobsterD
31-05-2015, 18:59
Great comments many thanks :)
Think I may of now finished the turntable and I'm really happy with it upgraded the bearing,installed an on/off switch and built a dustcover .

http://i886.photobucket.com/albums/ac68/RobsterD/IMG_0539_zpspmc2xzfh.jpg
http://i886.photobucket.com/albums/ac68/RobsterD/IMG_0538_zps9cvttrzk.jpg
http://i886.photobucket.com/albums/ac68/RobsterD/IMG_0542_zps73xepicg.jpg
Ali Tait
31-05-2015, 19:43
What design are the subs Rob?
RobsterD
31-05-2015, 20:24
Built from http://www.volvotreter.de/th.htm
Ali Tait
31-05-2015, 20:33
Cheers.
Jimbo
31-05-2015, 20:35
Great comments many thanks :)
Think I may of now finished the turntable and I'm really happy with it upgraded the bearing,installed an on/off switch and built a dustcover .

http://i886.photobucket.com/albums/ac68/RobsterD/IMG_0539_zpspmc2xzfh.jpg
http://i886.photobucket.com/albums/ac68/RobsterD/IMG_0538_zps9cvttrzk.jpg
http://i886.photobucket.com/albums/ac68/RobsterD/IMG_0542_zps73xepicg.jpg

What are those massive beasts next to your turntable:eek:
Ali Tait
31-05-2015, 20:37
That's the tapped horns. :-)
RobsterD
31-05-2015, 20:43
yes they are a little big,2 man lift and they scrape the ceiling :D
RobsterD
31-05-2015, 21:41
sorry had to post this as only discovered it with the lights on,my surname is dear hence the logo - cool reflection:cool:

http://i886.photobucket.com/albums/ac68/RobsterD/IMG_05431_zps6dmjzjku.jpg (http://s886.photobucket.com/user/RobsterD/media/IMG_05431_zps6dmjzjku.jpg.html)
tiguan
01-06-2015, 04:20
Great comments many thanks :)
Think I may of now finished the turntable and I'm really happy with it upgraded the bearing,installed an on/off switch and built a dustcover .

http://i886.photobucket.com/albums/ac68/RobsterD/IMG_0539_zpspmc2xzfh.jpg
http://i886.photobucket.com/albums/ac68/RobsterD/IMG_0538_zps9cvttrzk.jpg
http://i886.photobucket.com/albums/ac68/RobsterD/IMG_0542_zps73xepicg.jpg
Looks beautiful congrats...
İ have to make a dust cover to. Will look like similar most probably as my corners are curved as well.
RobsterD
09-09-2018, 17:54
updated pic now with a Lenco G88 platter .


https://imagizer.imageshack.com/v2/xq90/924/ALyZDq.jpg (https://imageshack.com/i/poALyZDqj)
paulf-2007
09-09-2018, 19:00
HI Rob, am I right in thinking you have the voxativ field coils?
karma67
10-09-2018, 08:47
That is one beautiful stand and turntable!
RobsterD
10-09-2018, 19:23
Cheers Jamie [emoji106]
Yep Paul I still have the Voxativ field coils , got Paul Hynes to build me a bespoke PSU for them sounding excellent.
Changed the platter to a G88 variant as I had one doing nothing ,supposedly better balance and finish -the stacking of Lenco platters doesn’t really have any benefit sound wise


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