ESP Project 23 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 30th January 2002, 10:10 PM   #1
tiroth is offline tiroth  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Pittsburgh, PA, USA
Default ESP Project 23

For ESP Project 23 would MJE2955/3055 be appropriate input devices? I happen to have a lot of these lying around.

Thanks.
  Reply With Quote
Old 30th January 2002, 10:24 PM   #2
paulb is offline paulb  Canada
diyAudio Member
 
Join Date: Jun 2001
Location: Calgary
I think they would if the voltage ratings are okay (I haven't looked). I don't think you need much gain, which is good because the 2955/3055 don't have much.
If you really want to be sure, you can email Rod - he's pretty good at answering inquiries.
  Reply With Quote
Old 30th January 2002, 11:27 PM   #3
lohk is offline lohk  Europe
diyAudio Member
 
lohk's Avatar
 
Join Date: Apr 2001
Location: Northern Noricum, near the Limes
No, I think this is no good choice.
Power transistors rarely are good input transistors.

Why don't you make lots of good sounding amplifiers with this devices?

Klaus
  Reply With Quote
Old 31st January 2002, 05:28 PM   #4
tiroth is offline tiroth  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Pittsburgh, PA, USA
Quote:
Originally posted by lohk
No, I think this is no good choice.
Really? This is not a circuit in the signal path, so "quality" is not really an issue as long as the circuit is still operational. Do you think it would not work correctly?

I should have mentioned that my rails are 42, so the max "normal" voltage the transistors should see is 39v, with a worst case (output shorted to unloaded rail) of 50v. I believe this is well within the 60v safe region. [output shorted to rail means I have bigger fish to fry, but I'd like to avoid secondary explosions in a fault state]

I would email Rod, but because he is so helpful to so many people I like to avoid bothering him where possible.

Thanks for your responses.
  Reply With Quote
Old 31st January 2002, 10:52 PM   #5
lohk is offline lohk  Europe
diyAudio Member
 
lohk's Avatar
 
Join Date: Apr 2001
Location: Northern Noricum, near the Limes
No, it is not a question of "quality".
MJE3055/2955s are designated output high current transistors, they need to be driven properly to function in an apropriate way. You can use them for input devices in sensing circuits for example, when high currents have to pass through. They have only low gain, and are quite non-linear at low currents, which can also be a problem here. And they are much bigger and more difficult to implement, and...
I think that they will not work the way you want. But if you insist, you can try it nevertheless ! It is up to you.
You can use - as Rod suggests - any transistor which meets the voltage specs. Current will be low, so possibly BC546/BC556 will work as an alternative. Boy, I have lots of these lying around ! (A zip-loc bag full of them actually...)

best wishes
Klaus
  Reply With Quote
Old 1st February 2002, 02:22 PM   #6
tiroth is offline tiroth  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Pittsburgh, PA, USA
Thanks for the suggestion lohk. I think I'll pick up some BC546/BC556 on my next order to be safe. :)
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
CDPRO2 Group Project (open source project) BrianGT Digital Source 147 8th August 2008 12:37 PM
My OLD Project....... cheap tube audio project!!! tube-lover Tubes / Valves 4 8th May 2008 10:26 PM
first project ceebmoj Full Range 5 23rd January 2008 08:51 AM
My first project, cool project. sorinsistem Solid State 3 19th January 2006 06:08 PM


New To Site? Need Help?

All times are GMT. The time now is 03:38 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2