Search found 40 matches

by Thomas_H
04 Sep 2017, 21:41
Forum: Amplifiers
Topic: EF86 AC4 inspired amplifier
Replies: 2
Views: 1918

Re: EF86 AC4 inspired amplifier

Yes, the Ef86 channels sound better, It's not a regular ac4, the extra triode between the EF86 and the El84 gives some extra gain, so the sound is not as weak as in the original. And the all in series configuratin, with the Ef86 in front of the two triodes has a lot of gain on tap, but with that pen...
by Thomas_H
20 Aug 2017, 15:28
Forum: Amplifiers
Topic: EF86 AC4 inspired amplifier
Replies: 2
Views: 1918

EF86 AC4 inspired amplifier

Hi, I finished a small amp based on the AC4 build here> http://www.dougcircuits.com/neon.html Just used one half of the 12ax7 as another preamp stage. https://i.imgur.com/3clwYDSl.png The preamp stages are switched by the jacks, giving the four different configurations. Not an AC4 anymore, but still...
by Thomas_H
28 Jan 2017, 22:51
Forum: Amplifiers
Topic: Fender Mini twin amp mods and some help needed
Replies: 11
Views: 4003

Re: Fender Mini twin amp mods and some help needed

Nice Upgrade! that speaker fits right in there. Just found that someone crazy enough to change the circuit and use normal sized tubes... http://profile.ultimate-guitar.com/Invader+Jim/pictures/gear/1173368/1352390 http://profile.ultimate-guitar.com/profile_mojo_data/1/4/0/0/140027/pics/_c1352390_ima...
by Thomas_H
28 Nov 2016, 21:51
Forum: Boutique Stompboxes dissected...
Topic: EarthQuaker - Tentacle (values and traces)
Replies: 5
Views: 2266

Re: E@rthQue@ker Tentacle (values and traces)

A green ringer in other words, I'm working on the same circuit right now and I found that Ge transistors do sound better. Also tried with a shottky and it was already better than the standard 1n4148. I observed that it gives a nice sound with only one diode too, it sounds fuller, but as a result the...
by Thomas_H
06 Nov 2016, 17:00
Forum: Amplifiers
Topic: Zvex - Nano Head
Replies: 219
Views: 134821

Re: Zvex - Nano Head

no idea about that, i know it is quite common in stereo amplifiers, and has something to do with the fact that the opamp requires a symmetric power supply. As I mostly build things for guitar, it's always mono, and runs on 9v. I once tried a cmoy build, that had something to split the 9v, and instea...
by Thomas_H
05 Nov 2016, 22:26
Forum: Amplifiers
Topic: Zvex - Nano Head
Replies: 219
Views: 134821

Re: Zvex - Nano Head

The phase inverter is used when you have a push-pull output stage, like in the imp amp, it inverts the signal that goes to the second output tube. So, while one tube is amplifying in one phase the signal at the other is perfectly mirrowed . http://www.valvewizard.co.uk/pp.html here you have some bas...
by Thomas_H
04 Nov 2016, 19:13
Forum: Amplifiers
Topic: Zvex - Nano Head
Replies: 219
Views: 134821

Re: Zvex - Nano Head

It would have to be the input driver correct yes, it comes right before the tubes, each output goes to one triode grid. There are two op275, one for each channel, as you can see at the pictures. What I found interesting about this is that the Imp amp uses both opamps in one IC for the Phase Inverte...
by Thomas_H
31 Oct 2016, 18:10
Forum: Amplifiers
Topic: Zvex - Nano Head
Replies: 219
Views: 134821

Re: Zvex - Nano Head

Ok, found the source of the pictures:
http://www.diyaudio.com/forums/tubes-va ... mpamp.html

and a schematic for the PI

Image
by Thomas_H
31 Oct 2016, 10:11
Forum: Amplifiers
Topic: Zvex - Nano Head
Replies: 219
Views: 134821

Re: Zvex - Nano Head

About the japanese one, there are not that much components, and the values are written on the board. I found the original guy or girl that designed it. He, or she, was selling the board in 2009/2010. http://lucythesoloist.blog33.fc2.com/blog-date-200902.html http://blog-imgs-24.fc2.com/l/u/c/lucythe...
by Thomas_H
29 Oct 2016, 17:56
Forum: Amplifiers
Topic: Zvex - Nano Head
Replies: 219
Views: 134821

Re: Zvex - Nano Head

Hi, I saw that project some time ago, don't think there is a layout or schematic available, but in the videos and pictures it's possible to identify that there are two 6021wa in PP. The pictures are from the Zvex photobucket. https://img.photobucket.com/albums/v295/zacharyvex/topviewiMPboard.jpg The...
by Thomas_H
25 Nov 2015, 18:07
Forum: Amplifiers
Topic: Building a kid's tube amp
Replies: 48
Views: 25928

Re: Building a kid's tube amp

Wow, nice build!

And thanks for all the pictures! You used a lot of recicled material, that is very nice! I always look for cheap/free stuff to use in my builds.

Most of the wood I use comes from old furniture, sometimes you find a good piece of solid wood!
by Thomas_H
23 Nov 2015, 21:10
Forum: Amplifiers
Topic: Building a kid's tube amp
Replies: 48
Views: 25928

Re: Building a kid's tube amp

Hi, I think a couple of hours of battery life would be plenty for a kid. Roughly speaking, how many Amp hours should it be to run a hybrid amp with a single tube, for 2 hours? Well, Greg stated somewhere he could play during 3 hours or so... For one tube, let's say a 12au7 the heaters would be consu...
by Thomas_H
22 Nov 2015, 11:35
Forum: Amplifiers
Topic: Building a kid's tube amp
Replies: 48
Views: 25928

Re: Building a kid's tube amp

Hi guys, This is a very Interesting thread, I start thinking about this and had some ideas... I also had a MS2 and the difference between clean and overdrive was really a problem, but if you look at the schematic the clean circuit goes directly into the power IC, while the overdrive has a fet before...
by Thomas_H
23 Sep 2015, 01:08
Forum: DIY Stompbox designs
Topic: 6N16B True tube overdrive with SMPS supply
Replies: 53
Views: 33816

Re: 6N16B True tube overdrive with SMPS supply

Hi,
I have a pdf file with some information here:
https://dl.dropboxusercontent.com/u/104 ... ianJTM.pdf

and made some videos:



Cheers
by Thomas_H
20 Sep 2015, 20:58
Forum: Amplifiers
Topic: "Superfly" - submini tube version of Doug H's Firefly
Replies: 69
Views: 47453

Re: "Superfly" - submini tube version of Doug H's Firefly

Image

here is my parallelse schematic
by Thomas_H
20 Sep 2015, 02:01
Forum: Amplifiers
Topic: "Superfly" - submini tube version of Doug H's Firefly
Replies: 69
Views: 47453

Re: "Superfly" - submini tube version of Doug H's Firefly

Hi, I tried the same thing with Rssian tubes. Put both triodes in parallel. Both plates go to the transformar, while both grids receive the signal from the previous tube. The cathodes are also in parallel. The main changes are: Since you're running the tube in parallel SE you need to reduce b+ to so...
by Thomas_H
27 Aug 2015, 12:22
Forum: DIY Stompbox designs
Topic: THE SFA - 1W all tube guitar amplifier
Replies: 6
Views: 4645

Re: THE SFA - 1W all tube guitar amplifier

Nice project! is this the same amplifier you were experiencing in an older thread? I guess I posted a lot in that thread... I have some questions...that sound more like some suggestions... as you're using the preamp triodes in parallel or only one triode, you could make it switchable to series too, ...
by Thomas_H
05 Aug 2015, 00:00
Forum: Amplifiers
Topic: Little Lanilei 1/4 watt Tube Recording Amplifier
Replies: 23
Views: 13865

Re: Little Lanilei 1/4 watt Tube Recording Amplifier

Hi, I would start adding high value cathode bypass capacitors, first at the output stage, around 100uF. If it's still not good enough I would add the others, but it could get a little muddy. I'm not sure, but the 12au7 is not the best tube for a good bottom end, I read somewhere the ecc99 works bett...
by Thomas_H
23 Jul 2015, 12:34
Forum: Amplifiers
Topic: Supro 1616t Layout with and without mods, build it!
Replies: 14
Views: 14260

Re: Supro 1616t Layout with and without mods, build it!

Hi!, finished my supro clone yesterday! Thanks for the layout by the way, it was really helpful! I changed some things, with diode rectification, an extra RC filter stage, bigger capacitors, and changed the tone cap position to block the HV (I saw this somewhere, now it is between HV and the tone po...
by Thomas_H
19 Jun 2015, 01:22
Forum: DIY Stompbox designs
Topic: 6N16B True tube overdrive with SMPS supply
Replies: 53
Views: 33816

Re: 6N16B True tube overdrive with SMPS supply

Hi guys, after some time a finnaly finished the head version, hope you like it https://i1303.photobucket.com/albums/ag159/Thomas_Eduardt_Hafemann/DSC_0389_zpssotzt1wg.jpg https://i1303.photobucket.com/albums/ag159/Thomas_Eduardt_Hafemann/DSC_0378_zpsfyxqnkn8.jpg https://i1303.photobucket.com/albums/...