DIY Audio Projects Forum
 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

DIY Audio Projects Forum

Welcome to the DIY Audio Projects Message Forum. Use these forums to discuss Hi-Fi audio and to share your DIY Audio Projects. Registration is free and required to post messages and view the file attachments. Registration will only take a minute and registered users do not see any advertisements. After you have completed the online registration process, check your email (including spam/junk folder) for the verification email to activate your account. New members are under moderation - so your posts will not be visible until approved by a moderator. See the Read Me 1st, Forum RULES and Forum FAQ to get started on the forum.

It is currently 18 Nov 2018, 20:49

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 203 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6, 7, 8 ... 21  Next
Author Message
 Post subject: Re: "Lacewood" Amp V2.0
PostPosted: 02 Apr 2017, 11:09 
Offline

Joined: 03 Jan 2017, 20:59
Posts: 25
I am almost ready to power on my Lacewood for the first time.
Just to be sure, the red/yellow and the green/yellow of the 270FX are connected together to form the circuit ground?
I have a variac and an insulation transformer so i will be careful when i will switch it on for the first time.
Pictures and impressions will follow.


Top
 Profile  
 
 Post subject: Re: "Lacewood" Amp V2.0
PostPosted: 02 Apr 2017, 11:28 
Offline
Project Author
User avatar

Joined: 06 Apr 2009, 10:08
Posts: 1480
Location: US Pacific Northwest
lowhifi wrote:
the red/yellow and the green/yellow of the 270FX are connected together to form the circuit ground?
Short answer: "Yes"

Attachment:
270FX Wiring Diagram.png
For the 270FX, the Red/Yellow is the HV center-tap and forms the basis of the power return / signal ground. The Green/Yellow is the center tap of the filament winding. This should not carry current (at least not much) but it should be tied to the signal ground (i.e. the Red/Yellow) to reference the filaments to ground. This can significantly reduce hum and provide a measure of safety for the tubes.


This post has a file attachment. Please login or register to access it. Only Registered Members may view attached files.


_________________
Matt
It's all about the Glass!
http://www.CascadeTubes.com
Cascade Tubes Blog


Top
 Profile  
 
 Post subject: Re: "Lacewood" Amp V2.0
PostPosted: 04 Apr 2017, 14:08 
Offline

Joined: 03 Jan 2017, 20:59
Posts: 25
It's alive, it's alive!!!

Image


Image

Thanks matt.


Last edited by lowhifi on 04 Apr 2017, 18:14, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: "Lacewood" Amp V2.0
PostPosted: 04 Apr 2017, 17:33 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4977
Location: Australia
Always nice when it all works at switch on.

_________________
Projects: "Grace" - Psvane 6SN7-SE Globe preamp | | "VoXUno" - Single driver MarkAudio 12P speaker | | "Lagoon Take 2" - Single stage tube preamp | Website: retro-thermionic


Top
 Profile  
 
 Post subject: Re: "Lacewood" Amp V2.0
PostPosted: 07 Apr 2017, 04:13 
Offline

Joined: 03 Jan 2017, 20:59
Posts: 25
mwhouston wrote:
Matt, how do you decide what value pot to use? I see some tube amps have 100K pots and others 250K pots.


And what about an L-PAD between the amp and the speakers, with low wattage the L-PAD will not cost much.


Top
 Profile  
 
 Post subject: Re: "Lacewood" Amp V2.0
PostPosted: 14 Apr 2017, 02:37 
Offline

Joined: 13 May 2016, 02:02
Posts: 97
Location: Javea, Spain
I've just sold my Vertical 6EM7 amp to a friend. I didn't want to as it sounds and looks so good, but I needed the cash to build this Lacewood V2.0 amp. Before I start buying can someone advise me on the power transformer. I live in Spain so the Edcor XPWR163 is a no go as they don't supply a 230V primary version. The XPWR139 560V (280-0-280 200mA) looks to be a good substitute. I'm going for all Edcor tranformers and chokes to keep it looking good on top, but these parts cost me a fortune as the transport and import tax add up to another 150 dollars on top of the item prices. Before I order I want to be sure about the power transformer. Any advice is welcome.


Top
 Profile  
 
 Post subject: Re: "Lacewood" Amp V2.0
PostPosted: 14 Apr 2017, 09:12 
Offline
Project Author
User avatar

Joined: 06 Apr 2009, 10:08
Posts: 1480
Location: US Pacific Northwest
John;

Go with the XPWR009 (or the XPWR007). Don't worry that the primary voltage is listed as 240v instead of 230v. Both will work in your situation.You are using a dropping resistor to tune the final B+ voltage in this design anyway, You'll be fine.

_________________
Matt
It's all about the Glass!
http://www.CascadeTubes.com
Cascade Tubes Blog


Top
 Profile  
 
 Post subject: Re: "Lacewood" Amp V2.0
PostPosted: 14 Apr 2017, 09:55 
Offline

Joined: 13 May 2016, 02:02
Posts: 97
Location: Javea, Spain
Okay Matt, I can get on and buy now. Really missing the 6EM7 but looking forward to the Lacewood.


Top
 Profile  
 
 Post subject: Re: "Lacewood" Amp V2.0
PostPosted: 14 Apr 2017, 10:46 
Offline
Project Author
User avatar

Joined: 06 Apr 2009, 10:08
Posts: 1480
Location: US Pacific Northwest
john55 wrote:
Really missing the 6EM7 but looking forward to the Lacewood.
They are different sounding amps. My wife was questioning me last week about differences between the two because she thought that they were different. And I agree with her. UL amps and SET amps have very different strengths and weaknesses. In my opinion, each one is better at different types of music.

_________________
Matt
It's all about the Glass!
http://www.CascadeTubes.com
Cascade Tubes Blog


Top
 Profile  
 
 Post subject: Re: "Lacewood" Amp V2.0
PostPosted: 14 Apr 2017, 20:29 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4977
Location: Australia
Must admit I do miss my last 6EM7 amp - "Abstinance". Just something about the 6EM7, in all of the four 6EM7 amps I built, is just so engaging. The tubes are easy to get and inexpensive. Simple to build and hard to go past.

All sold now with two, I know for a fact, still making lovely music.

_________________
Projects: "Grace" - Psvane 6SN7-SE Globe preamp | | "VoXUno" - Single driver MarkAudio 12P speaker | | "Lagoon Take 2" - Single stage tube preamp | Website: retro-thermionic


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 203 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6, 7, 8 ... 21  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: kitchi and 23 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
DIY Tube Projects :: DIY Tube Amp Kits :: DIY Speaker Projects :: DIY Solid State Projects :: DIY IC / Op-amp Projects :: DIY Phono Projects :: DIY Cable Projects :: Hi-Fi Audio Schematics
© diyAudioProjects.com - Terms of Service - Privacy Policy