• Please note that Audiokarma will be offline briefly for updates early on Monday morning, September 28th.

My Winter Project

hey Brick',
I was thinking of you; I saw a set of MO120 iron on ebay. Do you know if its output TX's are similar?
cheers,
Douglas
 
PakProtector said:
hey Brick',
I was thinking of you; I saw a set of MO120 iron on ebay. Do you know if its output TX's are similar?
cheers,
Douglas
Click to expand...

I'm not sure. I couldn't find any info on the MO120, did you mean M120? Those used 4x 8417, but I couldn't make out any transformer P/N for comparison.

If I could I would send you one for your tx measurements, just to see how much of a difference there is between hi-fi ones and this PA one. Seems heretical now that the amp is all together.:dunno:
 
Just found this thread. That amp is incredible. The layout of the internal parts and wireing is even more impressive then the external apperance.

You've just cause to be proud man. Wish I could do half as well.

Shelly_D
 
Beautiful job! Thanks for all the pics! I don't understand a great deal, yet, but everytime the uber-talented post thier builds, a little more starts making sense. :)
 
Thanks for the kind words everybody. I wish y'all could hear it too...a fest trip is up in the air this year but I'll make it a certainty for next year.:thmbsp:
 
whew! What's that smell? It must be this moldy old thread I just dug up :D

I did some changes to this amp a little while ago, and I finally got around to documenting them. I added e-linear feedback to the driver stage via the 70VCT on the output transformer. I was able to get this amp down to hush-quiet levels on the 96dB speakers then finally. :banana:
 

Attachments

  • e-linear_driver.JPG
    e-linear_driver.JPG
    125.4 KB · Views: 261
Micah brought this amp over to my place the other day, and we hooked it up in a system with Redgum CD player, Dared preamp, and ACI Sapphire IIILe speakers (see pic). It looks as good in person as it does in the pics, and it sounds great! I'm especially impressed with the power and definition in the bass - it puts my little ST-35 to shame in that respect - and it is also very smooth, sweet, and detailed. He has generously loaned it to me for a few weeks, so if the weather doesn't get too hot (this thing puts out a lot of heat!), there will be some happy listening hours here. :thmbsp:
 

Attachments

  • Micah's amp1.jpg
    Micah's amp1.jpg
    125.6 KB · Views: 321
Glad you enjoy it Rich! I gotta say I really liked them ACI speakers. My eyes are peeled :para: Good luck with the electric bill these few weeks :thmbsp::D
 
Had a listening session at Rich's house again. I brought the amp back this time, and did some measurements, which I haven't done since I modified the circuit. At 1 KHz, there is 0.05% THD at 1 watt; 0.5% THD at 10 watts. Sounds pretty sweet on the Advents, which I just got fixed up. Like Rich mentioned, this thing puts off a helluva lotta heat!
 
Micah, that amp doesn't have a power supply choke, does it?

Was wondering... as I'm thinking of building up my AP60s here (that I got from Tinkerbelle), with plate-plate feedback, like you were attempting to use earlier in the thread. I have a good pair of 300ma chokes... and there's room to put them on top of the chassis, one in each amp.

That might get rid of enough power supply noise, to make plate-plate feedback plausible, no?

Mine will be interesting- I, too am dealing with 600+ volts of B+... I'm thinking of using 6146 tubes, ala early model Ampegs and the original Acrosound Ultralinear amp. There's actually tertiary windings (approximately 25%) that would allow me to use these tubes in ultralinear, apparently... as I posted in my other thread about this...

Thanks!

Regards,
Gordon.
 
Not surprised that you got good distortion measurements - that amp sounded very clean to me!
 
You must log in or register to reply here.
Back
Top Bottom