DIY FirstWatt F4 and McIntosh C48? - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs
Home Forums Rules Articles diyAudio Store Gallery Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Pass Labs This forum is dedicated to Pass Labs discussion.

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 21st November 2015, 04:10 PM   #1
Lost in Translation
diyAudio Member
 
Join Date: May 2012
Location: Aarhus, Denmark
Default DIY FirstWatt F4 and McIntosh C48?

I have just picked up a McIntosh C48 and am wondering how best to connect it to a future build of a FirstWatt F4.

Do I need a Pass BA-2 VAS stage included in the f4 build, or can I connect the f4 straight to the C48 with good results?

Thanks!

Kind regards,
Peter
  Reply With Quote
Old 21st November 2015, 06:32 PM   #2
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Give a try and see.

  Reply With Quote
Old 21st November 2015, 06:50 PM   #3
jvhb is offline jvhb  Europe
diyAudio Member
 
Join Date: Nov 2013
Location: Countryside Zealand, DK
Looks like the C48 has 15 dB gain and 8v RMS Max unbalanced, so not quite enough to drive F4 to maximum power. But it may well be just fine, depending on the efficiency of your speakers and size of room etc. Like Mr Pass said, try it..
__________________
www.audioberg.dk
  Reply With Quote
Old 22nd November 2015, 09:47 AM   #4
Lost in Translation
diyAudio Member
 
Join Date: May 2012
Location: Aarhus, Denmark
Thank you Mr Pass! An excellent answer in the true spirit of DIY!

Thanks Jvhb. I would like to have the full power available, so I will stuff the BA-2. I have bought a partially built f4 from a guy who can also supply some of the hard to get parts for the BA-2. I will snap a few photos and a list if missing parts - just to keep track of it myself.
Peter.
  Reply With Quote
Old 22nd November 2015, 10:53 AM   #5
Lost in Translation
diyAudio Member
 
Join Date: May 2012
Location: Aarhus, Denmark
While I wait for another post to vbe approved, I have made the following "What I need to buy or check list for my build of the f4 amp. I will build the "Liberated" type f4 power amp:

What I need:
Case : Front / back / bottom / Top (I have humungous heat sinks)
Soft start module (CL60 or another high quality type)
Front Led
insulators
board mounting standoffs, w/ bolts and washers
Mounting bolts for fets w/washers, high quality keratherm insulators
Speaker Terminals and RCA Jacks
Power Connector
Power switch

BA-2 ”stuffing”
4
10K
R201, R202
4
47,5K
R203, R204
2
1K
R205
2
221R
R206
2
100R
R207
4
750R, 3w
R208, R209
4
47,5R
R210, R211
2
150R
R215
2
5K
P201
4
20pF
C201, C202
2
10uF, 35v
C203
4
1000uF, 35v
C205, C206, C208
(I have SJ109V+2SK170+IRF610)

I also have 2SK1530/2SJ201 for the output stage (missing from the build)
- Need to check 27K values that should be 22.1K on the board(s) (print fault in build diagram used for this)
  Reply With Quote
Old 25th November 2015, 08:39 PM   #6
Lost in Translation
diyAudio Member
 
Join Date: May 2012
Location: Aarhus, Denmark
Here is the McIntosh C48:Click the image to open in full size.
  Reply With Quote
Old 26th November 2015, 12:54 AM   #7
diyAudio Member
 
KevinHeem's Avatar
 
Join Date: Nov 2007
Location: Hudsonville, MI
I might take a step back if I were you. I realize you have the partially built F4, but ask yourself if this is the amp you would build if you were starting with a clean slate.
  Reply With Quote
Old 26th November 2015, 03:00 PM   #8
Lost in Translation
diyAudio Member
 
Join Date: May 2012
Location: Aarhus, Denmark
Kevin.

Why is this?

Originally I considered buying the Pass Int 30 (integrated) but then got a good deal on the McIntosh C48 pre. I had listened to a McIntosh 6600 on what was my speakers then (System Audio Pandion 2) but I did not like its sound. Then the dealer added the McIntosh C48 using the 6600 as power amp. That sounded much better.

But the biggest surprise to me was that at home with my Naim Nap 160 power amp on Rogers LS2 with both PC (ESI Juli@ sound card analogue out) and a moddded Thorens TD160 MKII+Morch UP4+ Denon 103R as souces, my set-up sounded very much better than it had any right to.

The McIntosh C48 has meant a very big leap in sound quality as compared to my 70s/80s Naim set-up. I would say close to Naim Nac 252 territory (another SS pre that I used to have in the house).

Still, I covet a slice of the Mr Pass sound.

My study is quite small, so I don't need that much amplification in here.

Last edited by Rosewind; 26th November 2015 at 03:02 PM.
  Reply With Quote
Old 26th November 2015, 03:55 PM   #9
diyAudio Member
 
KevinHeem's Avatar
 
Join Date: Nov 2007
Location: Hudsonville, MI
I'm sure the BA2 vas and F4 would make nice sounding amp. I just think there might be an easier way to build yourself a NP amp. If you were to build an F6 you could buy the deluxe 4U chassis, F6 kit with board and transformers, jfets, insulators, power supply board, and I believe a hardware kit all from the store. The chassis is all predrilled and taped. You just need to source passive components, transformer, and assemble. So you would have something relatively easy to assemble by following the build guide. It would be consistent with other members builds who will be helping you along the way, especially when it comes to troubleshooting. In my experience there's always troubleshooting.

I understand the F6 kit and 4U deluxe chassis are out of stock so it would take a little patients.

Last edited by KevinHeem; 26th November 2015 at 04:10 PM.
  Reply With Quote
Old 26th November 2015, 05:05 PM   #10
Lost in Translation
diyAudio Member
 
Join Date: May 2012
Location: Aarhus, Denmark
The 4U chassis is available in Italy. I have inquired. I don't know if it is pre-drilled. The Danish DIY from whom I bought the partly stuffed boards and some good parts lives half an hour away from me. He has given me good advice + I have a friend who will help me.
  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
DIY FirstWatt F2 speaker amp zzffnn Swap Meet 16 26th August 2012 03:30 AM
Improving a FirstWatt-built F4 jeffreybehr Pass Labs 9 28th February 2012 09:17 PM
Signs your Firstwatt DIY is unstable? Russellc Pass Labs 20 13th April 2011 06:49 PM
WTB firstwatt f4 clone Ang Swap Meet 4 1st August 2010 10:57 PM
WTB FirstWatt F1 and F4 boards toufu Swap Meet 1 11th August 2009 06:31 PM


New To Site? Need Help?

All times are GMT. The time now is 07:31 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
Copyright 1999-2016 diyAudio

Content Relevant URLs by vBSEO 3.3.2