Millett PP or Allen Wright's PP-2c or? - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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 25th March 2012, 12:02 PM   #1
diyAudio Member
 
nanchangbob's Avatar
 
Join Date: May 2009
Location: China
Default Millett PP or Allen Wright's PP-2c or?

Ok guys I don't post much here but I do a lot of reading and I would like some advice. I have done some preamp builds and various other products and done a lot of mods but this will be my first amp build.

What I have now are a pair of 5k James 50 watt output transformers. I found some nice aluminum cases that are 15.75 inches by 11.6 by 3 inches.

I am looking at 3 different amps and would like to know your opinions.

The first is the Millett Uniamp.

UNIAMP2_sch.pdf

This amp look fairly easy and I have some 5U4's waiting for a home. Pete said my James would be fine. I like the fact that it has the PCB to work from..

I also like Pete's PP-driver board. I like the fact it has the CCS and uses FET's for loads. I would need to build the power supply but the board does most of the rest. I don't know much about the tubes he uses in this build?

ppdrv.8.gif

The last one I was considering at this time. That doesn't mean I'm closed to suggestions. It is Allen Wright's PP-2c. I would use Salas SSHV2 regulators if I did this build. This would be a little more work for me.

PP-2C_map.pdf

I would really like to get your thought and if possible personal experience with these designs. I will be back in the U.S. visiting family in June and I want to gather my supplies when I'm there.

The iron to finish these builds would be more or less the same cost. I contacted James for the Power transformers and Choke. I also contacted K @ K audio for the price of the Lundahl's in case I go with the PP-2. The PP-2 would cost more than the others but that isn't my biggest concern. I really want to build the nicest amps I can.

I will be using the amps with my Vandersteen 2 sig II and Aikido preamp. My room is not very big but I think 25 watts and above would be best. I would appreciate your thoughts.
__________________
A great day to listen to music.
  Reply With Quote
Old 25th March 2012, 12:32 PM   #2
John C is offline John C  United Kingdom
diyAudio Member
 
John C's Avatar
 
Join Date: Jan 2004
Location: UK
Hello,
I had quite a few discussions with Allen before he sadly passed... I have accumulated most of the bits for the PP2 amp. I will be starting soon to build this. Allen was very adamant that this amp if built to exactly his design would be very, very good. I have his pre-amp cookbook too... This is a very entertaining read. One of the sweetest amps I played with was the Puresound A30. I replaced most of the parts in it with much better one's and it was superb. Hardwired it in triode mode. To my ears the imaging was far more stable.
I have all Shinko resistors, Mundorf SGO caps, Mundorf Tubecaps for the build of the PP2. Just waiting for the Transformers now.
Best of luck with your choice.

Regards

J
__________________
L8TER... JC
  Reply With Quote
Old 25th March 2012, 04:25 PM   #3
diyAudio Member
 
Join Date: Sep 2009
Location: Aarhus, Denmark
I vote for the PP2c.
I've built the PP1cs and now an extreme version using Tentlabs autobias e-chokes, 6CA7 and shuntregs for the driver stage.
Don't forget to build the matching RTP3 preamp... ;-)
__________________
"People can't do what they should: room acoustics and speaker design - so they do what they can: new amps, cables etc." (Lidia)
  Reply With Quote
Old 25th March 2012, 05:05 PM   #4
diyAudio Member
 
neonthecat's Avatar
 
Join Date: Jan 2010
Location: Left Coast
Bob...
I'm very happy with my Millett Uniamps driving the same Vandersteen speakers as you mention. I've found the 25w (?) they put out are more than enough for my average-size room. Actually, they sound much more powerful than they are. Easy to build and trouble free.
__________________
"We provide the music, you provide the silence." - Charles Mingus
  Reply With Quote
Old 25th March 2012, 06:51 PM   #5
diyAudio Member
 
nanchangbob's Avatar
 
Join Date: May 2009
Location: China
Nelson the autobias is very is very interesting. Never seen that one before. I think that will be part of the upgrade. I don't want to overwhelm myself on my first amp build.

I haven't seen any builds for the PP-2c yet .

As far as the Uniamp goes. I have a question. Sorry I'm always trying to tweak or improve things. Is there any reason why R9 couldn't be changed to a CCS? Also what about removing R4 and R5 and replacing them with some MOSFETs?
__________________
A great day to listen to music.
  Reply With Quote
Old 26th March 2012, 01:29 AM   #6
rhone is offline rhone  Australia
diyAudio Member
 
Join Date: Dec 2005
Location: Melbourne
I built the PP2C a while ago, using the Salas reg on the input stage and EH 6CA7s. Sounded good. Allen once ended a post with the something like "I want speed and I want definition" which gives you a good idea of the sound. I've recently changed the output tubes to 6B4Gs for even more dynamics. It's a clean, powerful sounding amp.
  Reply With Quote
Old 1st April 2012, 09:34 PM   #7
lordoff is offline lordoff  Bulgaria
diyAudio Member
 
Join Date: Oct 2006
Hi,
I'm in similar route.
Almost ready with parts to build PP2-C ( I'm convinced that this design is from best PP designs)
So sadly that is not possible to ask directly Mr. Allen Wright for some details. Very, very sadly. Respect to him! Rest In Peace!
I read several times his Preamp Cook book, still have a ton of questions

But from long time ago I have a big affinity for transformer coupling.
I like a lot Linn Olson's designs, Mr. Kevin Carter's front-end design. Exelent!
So I start wounder why not possible to use this topology:
input transformer - diff. cascoded (by Allen Wright) driver - interstage transformer - output diff.stage
(pentode or not, CCSed or not, harmonic equalised or not (by WE), whatever you like)
Yes, I know Mr.Wright, that is against your religion.... :-)
Please, forgive me
  Reply With Quote
Old 1st April 2012, 10:03 PM   #8
diyAudio Member
 
Shoog's Avatar
 
Join Date: Aug 2002
Location: Eire
If you don't have a balanced preamp then placing an input transformer at the front is a really good idea as it allows for you to drive the input balanced from a single ended.

Shoog
  Reply With Quote
Old 1st April 2012, 11:43 PM   #9
lordoff is offline lordoff  Bulgaria
diyAudio Member
 
Join Date: Oct 2006
Shoog,
for me no doubt that input transformer will make things better.
I have LL1544 and LL1676 and 74 all ready for experimentation.
I will use even with balanced preamp. ( my plan is to build Raven or Parafeed by Mr.Davenport design)
RTP3 by Allen, is excellent design but... "little" complicated for me, by now.

Anyway, main question to decide: possible to make cascoded diff. stage to be transformer loaded.
I read a lot diyaudio, lot of books - old and not so, still no answer.
Nowhere dont see this. May be I try to make things unnecessarily complex?
Who knows...
If this topology works - we will have a project called Wright/Olson driver stage :-)
OK guys, I just trying to get good things from two worlds.
Unfortunately, for me is impossible task то make some simulation.
Must try on breadboard, but want to be prepared... don't be OUCH, right
  Reply With Quote
Old 2nd April 2012, 09:24 AM   #10
diyAudio Member
 
Shoog's Avatar
 
Join Date: Aug 2002
Location: Eire
Quote:
Originally Posted by lordoff View Post
Shoog,
for me no doubt that input transformer will make things better.
I have LL1544 and LL1676 and 74 all ready for experimentation.
I will use even with balanced preamp. ( my plan is to build Raven or Parafeed by Mr.Davenport design)
RTP3 by Allen, is excellent design but... "little" complicated for me, by now.

Anyway, main question to decide: possible to make cascoded diff. stage to be transformer loaded.
I read a lot diyaudio, lot of books - old and not so, still no answer.
Nowhere dont see this. May be I try to make things unnecessarily complex?
Who knows...
If this topology works - we will have a project called Wright/Olson driver stage :-)
OK guys, I just trying to get good things from two worlds.
Unfortunately, for me is impossible task то make some simulation.
Must try on breadboard, but want to be prepared... don't be OUCH, right
I think it theoretically possible, but probably not worth the effort. The obvious way still requires cap coupling to the IT - which to my mind is just adding complexity without any technical gain.
Personally I would just stick with the input transformer. If I was going to try anything it would be DC coupled.

Shoog
  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
Question re Allen Wright PP-1cs lilolee Tubes / Valves 19 17th December 2014 09:44 AM
Don Allen CakePan PP tube amp using 12V6 tubes xecluded Swap Meet 3 29th September 2010 08:28 PM
EL84 PP output transformer for 6L6 PP class A engels Tubes / Valves 8 30th May 2007 10:45 AM
PP-Triode , PP-UL , PP-Pentode-strapped-as-Triode percy Tubes / Valves 23 22nd January 2007 01:36 AM


New To Site? Need Help?

All times are GMT. The time now is 06:49 PM.


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