Another MoFo

What people are working on at the moment
User avatar
Ray P
No idea why I do this anymore
Posts: 6294
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

#166 Re: Another MoFo

Post by Ray P »

Good stuff Phil - looks like the project is working out well.
Sorry, I couldn't resist!
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#167 Re: Another MoFo

Post by pre65 »

Ray P wrote: Thu Jul 09, 2020 6:49 pm Good stuff Phil - looks like the project is working out well.
Thanks Ray.

I drilled and tapped the mosfet and PCB mounting holes and populated the second PCB a while ago, but that's it for tonight.

The MOT spade terminals were smaller than I realised, so I've "bodged" them until the proper 4.8mm ones turn up

I'd like to think I'll have stereo MoFo's this weekend. :D
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#168 Re: Another MoFo

Post by pre65 »

I've just fired up the second unit, and I'll leave it playing on the test bench for an hour before tweaking the bias to its final value.

I don't anticipate getting them set up in the main system tonight, but something to look forward to in the morning. :)
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#169 Re: Another MoFo

Post by pre65 »

Well, of course, I couldn't wait till the morning. :)

I'm playing a Carpenters CD, and the sound quality is different from what I'm familiar with.

Seems clearer, and more expansive. Bass is clearer, and a bit more of it, but it's not prominent. Karens voice is even more delightful than I remember. Can't find any disadvantages at the moment.

Obviously need more listening time with different types of music to really get a handle on things.
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
steve s
Shed dweller
Posts: 2829
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#170 Re: Another MoFo

Post by steve s »

I found it's a nice mix .. I think mine combines all the advantages of no output transformer valve amp and what solid state aspires to be.. . If that makes sense
No colour/ greyness/ lack of detail
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#171 Re: Another MoFo

Post by pre65 »

Stereo MoFo's. :D

After a bit of thought I went for the BIG 6800uf capacitors, and mounted them as close to the PCB as possible.

Image
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#172 Re: Another MoFo

Post by pre65 »

I've switched off now, 'cos I'm going for a walk soon.

I've tried a varying selection of my musical tastes, but as I'm liking what I hear I'll play some more when I return.

I'm considering getting a pair of Hammond 193V chokes, 150mH @ 3A, now that the amp is worth refining.

What chokes did you use Steve ?
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
steve s
Shed dweller
Posts: 2829
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#173 Re: Another MoFo

Post by steve s »

I used 193t, I cant imagine a bigger choke will make it sound any better unless you need more power
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
User avatar
Ray P
No idea why I do this anymore
Posts: 6294
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

#174 Re: Another MoFo

Post by Ray P »

pre65 wrote: Sat Jul 11, 2020 11:30 am Stereo MoFo's. :D
:thumbup:
Sorry, I couldn't resist!
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#175 Re: Another MoFo

Post by pre65 »

steve s wrote: Sat Jul 11, 2020 3:24 pm I used 193t, I can't imagine a bigger choke will make it sound any better unless you need more power
You may be right Steve. :)
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
ed
retired
Posts: 5384
Joined: Thu Jun 21, 2007 4:01 pm
Location: yorkshire
Contact:

#176 Re: Another MoFo

Post by ed »

if you really must tinker with it why not try a couple of exicons. I'm willing to bet it will be more enlightening than a couple of expensive chokes. They might cost you £4 each but well worth the experience.
There's nowhere you can be that isn't where you're meant to be
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#177 Re: Another MoFo

Post by pre65 »

Thanks Ed, but I don't have the skills to select one that would work, and then it's a gamble.

I'll stay with what I've got for now.
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
steve s
Shed dweller
Posts: 2829
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#178 Re: Another MoFo

Post by steve s »

ed wrote: Sun Jul 12, 2020 5:21 pm if you really must tinker with it why not try a couple of exicons. I'm willing to bet it will be more enlightening than a couple of expensive chokes. They might cost you £4 each but well worth the experience.
Reading up, my impression is there are advantages to having the choke there, it works similar to choke loading a valve ?
Also reading DIY audio, mosfets can start to sound a little grey when used as a voltage gain amplifying device...thats only what I've read so dont shoot me down... but this thing does not sound grey, just very open.
The amp sounds different.. I think it's good,
But what to I know..
If i messed with a suitable exicon or any other mosfet (unless I was sure otherwise) I'd probably still put a choke with it.. I like what it does
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
User avatar
Nick
Site Admin
Posts: 15706
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#179 Re: Another MoFo

Post by Nick »

Unless I am missing something, that circuit wont work without a choke. I think ed means use a different mosfet as the power device.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
steve s
Shed dweller
Posts: 2829
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#180 Re: Another MoFo

Post by steve s »

Nick wrote: Sun Jul 12, 2020 7:18 pm Unless I am missing something, that circuit wont work without a choke. I think ed means use a different mosfet as the power device.
One of my many skills is misreading nick, my apologies Ed.. 😃
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
Post Reply