diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Acoustic Fun (http://www.diyaudio.com/forums/acoustic-fun/)
-   -   (new internal photo added)AcF's new tube amp projects (http://www.diyaudio.com/forums/acoustic-fun/156287-new-internal-photo-added-acfs-new-tube-amp-projects.html)

Maniac 6th December 2009 06:44 PM

(new internal photo added)AcF's new tube amp projects
 
Hello everyone,

Here's some of the stuff that we are working on at the moment, just wondering what's everyone's take on these stuff?

http://img69.imageshack.us/img69/7677/img3295w.jpg

This is an integrated amp based on the Russian OTK grade 6P1P in PP config (Similar to 6AQ5, but using B9A pinout, instead of B7A.) and 6N2P as drivers (similar to 12AX7 but lower gain, we have tried it with 6922 as well and it worked quite nicely here too.)

The output power is about 10W, and drives my rather power hungry Acoustic Energy AE-120SE surprisingly well. The transformer that you see in the picture is the power transformer, while the two output transformer is hidden inside the chassis. The smaller output transformer not only performs well, but actually provided some very strong bass performance that wasn't expected when I first plugged it in.

I have taken some time tuning this amp so that it sounds rather enjoyable for everyday listening. When we started to work on this amp, we tried to use what parts we have on hand for the high voltage caps... now that sucked rather badly. The high freq sounded a bit on the harsh side and kinda sharp, after more or less an overhaul of the caps inside, and replacing them with quality caps like that BHC 100uF/400V that I have mentioned in the other post. The amp now sounds positively engaging.


The other aspect of the amp is being considered carefully as well, the volume control for example, will be using a 21 step series stepped attenuator, and the input selector is done via precision telecom grade signal relays. I personally hate running a pile of signal wires to the a manual selector switch, as it in my view is doing more work for less result. I much prefer to use the selector switch as a controller to control the relays for input selection. Less mess, less wiring.



Estimated price is around $300~$330 USD, shipping is about $45~50USD to North America and Europe Regions. Lower for Asia regions and higher for South America and Africa regions.

Here's a short recap of the features of this amp.
Power: 10W output, 8Ohm taps only (Something's gotta give for an amp this small)
Power tube: Russian OTK 6P1P-EV (Similar to 6AQ5 but in B9A form)
Signal tube: Russian OTK 6N2P-EV (Similar to 12AX7, but this amp had been tested to work with 6922 as well)
Inputs: 3 input, relay switched. (Front panel LED will indicate the input currently used.)
Volume control: Precision 21 step series attenuator.
Construction Method: High quality PCB with minimal external wiring for highest reliability.
Weight: appox 3.5KG net.
Voltage compatibility: 115V at the moment, will see about building a 115V-230V capable transformer in the mean time.
Dimention: appox 280 x 215 x 150mm


What do everyone think about this amp? Should we jump the gun and go ahead on producing it? Knowing that there will always be people wanting to mod their equipments, the wirings inside will be marked in a way that makes it easy for modder to take apart and put together. For example, transformer wiring will be numerically labeled, so that you can put them back together quickly and easily. Just solder back the wire in sequence!


I'm also in the process of building B7A to B9A adapter for these amps, so that you will be able to use 6AQ5 tubes with this amp as well. I just need to wait for the slow setting epoxy to arrive before I can start to build the adapter plugs. :D


Of course tho, warranty will be voided once modding had been done on the unit (for the record, swapping tubes is not considered as modding. ;) ), but we will however, continue to provide service and support on helping you to find the problem if you have encountered trouble during the mod-quest. :D





Also showing this time is a EL34 SE amp, this time it is populated with Chinese Shuguang tube.

Please note, if this unit enters production, the output transformer will not be capped with chromed cover, but black like the power transformer. Also the output transformer will not be as huge, as these two output transformer are just way overkill, and it just something that I got years ago. Actual production unit will be using new production output transformer.

http://img704.imageshack.us/img704/2056/img3293w.jpg
This is the view from the front, same 21 step attenuator, relay input select and LED input indicator. Of course, single-ended class A output of appox 12W, and also drives my AE120SE well with smooth flowing music and still able to provide a strong bass performance.


http://img704.imageshack.us/img704/9955/img3294w.jpg
The rear view, 3 sets of input as usual, but this time due to the much larger chassis and transformer, 4 ohm tap is also available.


Basically, due to the massive weight of this unit, the shipping will shot right up to around $80USD, while the unit will be priced around $450USD. I'm not THAT keen of putting this unit on production, as it weights a little much for express international shipping (we all know that we want our toys to arrive fast, aren't we? ;) ). Still, it can't hurt to throw the idea around and see how everyone like this one. :)


Here's the basic spec of the EL34-SE
Power: 12W output, 8 and 4 Ohm taps
Power tube: Shuguang EL34
Signal tube: Shuguang 6SN7
Rectifier tube: Shuguang 5Z3P
Inputs: 3 input, relay switched. (Front panel LED will indicate the input currently used.)
Volume control: Precision 21 step series attenuator.
Construction Method: High quality PCB with minimal external wiring for highest reliability.
Weight: appox 13KG net.
Voltage compatibility: 115V at the moment, will see about building a 115V-230V capable transformer in the mean time.
Dimention: appox 350 x 260 x 190mm


Please let me know what do you guys/gals think of these two amps. :D any comments, suggestions and opinions are much appreciated! No, messengers won't be shot on sight when bearing bad new... :headshot:

Maniac 9th December 2009 01:02 AM

Well, here's what I have promised to those who have asked. ;)

The innards of the 6P1P PP Amp


http://img706.imageshack.us/img706/4565/img3732w.jpg
The "bottom end" before the tool is applied...




http://img27.imageshack.us/img27/3100/img3733w.jpg
The actual innards of the 6P1P, the small caps and wires are there to power the input selector relays, and will be fully integrated onto the PCB for the production version. The rosen on the board are due to experiments done on the board, the actual production board will be looking a lot like the photo for EL34 SE, as it hasn't been through as much modding as this one had. The 4 coupling caps will be replaced by Bennic PP caps in the production unit.



http://img30.imageshack.us/img30/20/img3730w.jpg
The "bottom end" of the EL34 SE amp.


http://img10.imageshack.us/img10/3756/img3731wi.jpg
This is done to the neatness and quality of production unit, as you can see, it is quite a bit cleaner than the test mule above, and that's how we like to ship our products. The yellow coupling cap will be replaced with quality Bennic PP caps if it is put into production. We will also study if the 100uF/400V BHC cap that we have here is enough for this amp or not.


There are people who prefer direct wiring for tube amps, and we respect that. However, our preference for PCB is rooted in a few reasons. It standardize the production of the unit, there will not be as much variation from unit to unit. Thus once an unit is fine tuned and more or less "perfected", the next units and all the units after that will not vary much from the standard. The same could not be said for the unit built via direct wiring method, as there are more variables and more places to watch out for. Tho I have to agree that well crafted direct wiring unit is an art in itself, but the price will be priced like a piece of art too.


Thanks

David

lordearl 17th January 2011 11:39 PM

Looks good, well made, good specs. I use a 6SN7/6V6 PP that cost three times as much, but would certainly be willing to compare it!


All times are GMT. The time now is 10:31 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2