Biyang WANG AMPS VT-1H mini guitar amp - diyAudio
Go Back   Home > Forums > Live Sound > Instruments and Amps

Instruments and Amps Everything that makes music, Especially including instrument amps.

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 26th June 2015, 08:26 PM   #1
diyAudio Member
 
Join Date: May 2010
Location: was Chicago IL, now Long Beach CA
Default Biyang WANG AMPS VT-1H mini guitar amp

The first brand new guitar amplifier I've ever bought "new" instead of built or repaired! Also my first Chinese amp...LOL! Hand-wired by a family operation.

Really cute circuit:

Most mini-amps are single-ended in the belief they are simpler, but end up inefficient and require a large power supply, filters, and heavy output transformer. They tend to model after the classic Champ.

This takes a different push/pull route. All tubes are dual triode preamp tubes, which actually work acceptably as output tubes when used in push/pull.

The first stage has both halves of a high-gain dual-triode in parallel.

Then there is a one-knob tone control, with the counter-clockwise "bass" setting shunting the pre-volume (right after the coupling cap from the previous plate) treble to ground via a cap, and the clockwise "treble" shunting the treble across the volume pot, like a variable "bright" switch. Not much gain loss.

Then the first side of the second high-gain preamp tube gives gain. The second half of that tube is a paraphase phase inverter.

Then the two halves of a moderate-gain higher-current dual triode are used as the push and pull output stages. Each stage pushes into a half of a 10K - 0 -10K primary on the small output transformer, with a single secondary labeled "8 to 16 ohms."

This is the smallest 3-tube push/pull I've ever seen. I'm still waiting for it to arrive. Judging from the YouTube clips, this thing is killer.

I guess it also shows that Chinese tubes are cheaper in China than Chinese transformers! Otherwise you could build a nice little 2-tube push/pull amp using an interstage transformer as the phase inverter.
  Reply With Quote
Old 26th June 2015, 08:28 PM   #2
diyAudio Member
 
Join Date: May 2010
Location: was Chicago IL, now Long Beach CA
Yes, I know smaller tubes exist...
  Reply With Quote
Old 26th June 2015, 08:30 PM   #3
diyAudio Member
 
Join Date: May 2010
Location: was Chicago IL, now Long Beach CA
WIMA caps, metal-foil resistors, fiberglass PCB, ceramic tube sockets.
  Reply With Quote
Old 3rd July 2015, 10:53 AM   #4
diyAudio Member
 
Join Date: Jan 2008
Search for Hghes Kettner Tubemeister 5. Push-pull triode output stage 5W, one preamp tube. Definately better than this Chinese amp.
  Reply With Quote
Old 3rd July 2015, 12:57 PM   #5
diyAudio Member
 
Join Date: Sep 2013
Location: Minneapolis, MN
Of course the H&K is better. It's normally three times the price too. The big box retailers right now have $200 off the H&K, otherwise it's $169 for the Wang vs. $499 for the H&K. Not comparing apples to apples.

Last edited by boobtube; 3rd July 2015 at 12:59 PM.
  Reply With Quote
Old 3rd July 2015, 01:53 PM   #6
diyAudio Member
 
Join Date: Dec 2013
Location: Fayetteville, AR
I'm a bit intrigued by Rob Robinette's micro amps that use triode power amps, like the micro-Bassman.

I'm not at home, and I can't remember the tubes, but I got a lot off eBay that included some high current triodes that I think are normally used for triode power amps. At some point (after I complete my 4 or so pending projects) I'd like to do something with those.
  Reply With Quote
Old 3rd July 2015, 02:17 PM   #7
diyAudio Member
 
Join Date: Sep 2013
Location: Minneapolis, MN
Great reference, pdavis. He has a great site for mods and ideas. Got his site in my favorites. This amp you provided the link to is more in the category of the Wang
  Reply With Quote
Old 3rd July 2015, 02:25 PM   #8
diyAudio Member
 
Join Date: Dec 2013
Location: Fayetteville, AR
I just happen to have been perusing his mods last night and I've had the micro-Champ and micro-Bassman in the back of my mind since I got those triodes. It looks like the Wang is OTL. I don't have a good handle on how to do those. I'd love to see a schematic. All the examples I've seen of OTL amps use 500-800ohm speakers.

Sent from my SAMSUNG-SM-G900A using Tapatalk
  Reply With Quote
Old 3rd July 2015, 05:40 PM   #9
Bone is offline Bone  United Kingdom
diyAudio Member
 
Join Date: Jun 2004
Location: Dorset, UK
Output transformer is inside the case mounted on the main PCB.
  Reply With Quote
Old 3rd July 2015, 06:30 PM   #10
diyAudio Member
 
AudioFreak88's Avatar
 
Join Date: May 2014
if its any of those WIMA Box/metalized I would be ripping them out....
  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
Guitar Mini Amp with PAM8610 Module mnesarco Class D 5 14th April 2015 09:24 PM
12 volt /5 amps off mains vs 12 volts/3 amps off battery power for mini-amp? Jaxhouse Power Supplies 3 20th June 2014 11:44 AM
I have a design decision to make - mini guitar amps KFW Instruments and Amps 2 10th October 2012 09:52 PM
Mini guitar amp from a Webcor tape amp, is it possible? StiffHand Tubes / Valves 9 28th July 2006 01:31 PM


New To Site? Need Help?

All times are GMT. The time now is 11:46 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2