DIY Dodd Buffer

ebag4 · « **Reply #280 on:** 26 Apr 2010, 08:15 pm »

Quote from: TrungT on 26 Apr 2010, 07:26 pm

ED

Dodd buffer rules
Good ideal to keep the battery inside the chassis.

Thanks Trung. If I can get 10 hrs out of the 5ah batt that should be all I need. If I decide that I need more than the 5ah can give then it is a simple matter of removing two wires and connecting to the Neutrik with the batt instead of the charger.

Best,
Ed

Mariusz · « **Reply #281 on:** 26 Apr 2010, 09:54 pm »

Quote from: ebag4 on 26 Apr 2010, 07:20 pm

Mariusz, I considered this as well. The solution I came up with although I decided not to implement was to mount a bracket to the lid that would bend down and under the tube block then back up to the lid. You could probably do this from the bottom of the case as well, that may work better. I was going to use some 1" wide aluminum bar stock that I have. Of couse only about half the tube would penetrate the top but that should be enough to make changing tubes without rmoving the lid doable.

Best,
Ed

Came to the same conclusion as you Ed except, I am a bit more in favor of a bottom "riser" mounting solution.

Mariusz · « **Reply #282 on:** 27 Apr 2010, 04:20 am »

OK,........ It took me half an hour to do it but it's a success.....almost.

Gary my friend
I have to ask you for another 10 pin header.

But good news is - no need to fix my screw ups.
It would also make sense to get those by-pass caps and extra Cardas solder.
Please let me know the total via PM Gary.

And one less request for all those who opt to go with the ugly boxes -
is it possible to get some logo sticker for those DIY enclousures ?
I have this cheap wood burning tool with letter set which might work but if you have something more original....... it would be just lovely!

Regards and
thanks for everything
in advence

Mariusz

TrungT · « **Reply #283 on:** 27 Apr 2010, 04:29 am »

Mariusz
Another option for the panel logo:
Ask Gary nicely he may send you a DODD AUDIO logo ( stick on) may be in a thin wood .. some sort.
I think Gary is setting up his engraving machine.

Mariusz · « **Reply #284 on:** 27 Apr 2010, 04:46 am »

That would be really nice.
PLEASE!!!!

PS
to make it easier for others I finished a wooden box with clear 1/4" plexiglass top.
It should make nice addition to Gary's "Ghost" enclosure.
I will also do my best to rise the tube pot so it is accessible from the top.
It will be small enclosure tho - 8"x8"x5".

Cheers
Mariusz

TrungT · « **Reply #285 on:** 27 Apr 2010, 05:06 am »

Mariusz
Can you rise the tube by adding a block (wood??) the height needed?
Look at the way the tube holder build, you can not rise too high up though, maybe 1/2 of the tube showing.

Mariusz · « **Reply #286 on:** 27 Apr 2010, 05:21 am »

Quote from: TrungT on 27 Apr 2010, 05:06 am

Mariusz
Can you rise the tube by adding a block (wood??) the height needed?
Look at the way the tube holder build, you can not rise too high up though, maybe 1/2 of the tube showing.

Yupp, you could use wood block riser or other
similar. 1/2 tube showing might not be enough tho ..... we will see.
Clear cover will be removable and •no screws whatsoever• but I would like to try to show some possibilities for fellow audiophiles wondering about easy tube access.

I'll dry fit everything tomorrow and report back the results.

TrungT · « **Reply #287 on:** 27 Apr 2010, 05:32 am »

Double check with the ruler, you can get 2/3 of the tube out, which made possible to remove the tube.
If you use a block of wood, cut little long and cut to fit.
(easy said than doing it

)

Mariusz · « **Reply #288 on:** 27 Apr 2010, 05:54 am »

Wires on both sides of the tube socket will have to be banded a bit tho.... but it shouldn't be an issue.

TrungT · « **Reply #289 on:** 27 Apr 2010, 06:01 am »

Stand on the tube socket, the wires should be nicely flat

Don't forget to shot some photo.

Mariusz · « **Reply #290 on:** 27 Apr 2010, 06:04 am »

Quote from: TrungT on 27 Apr 2010, 06:01 am

Stand on the tube socket, the wires should be nicely flat
Don't forget to shot some photo.

I'll try

ebag4 · « **Reply #291 on:** 27 Apr 2010, 06:51 pm »

Alright guys, I need to share what I am hearing. First, let me cover what I am hearing it on. I have been listening to the V-1 coax for about a year now (couldn't believe it had been that long so I verified via Paypal). I listened to them with my Augies until about a month ago when I sold the Augies, I am in the process of building the V-1s. Because of this I can only address what I am hearing from 200Hz and up.

For the last two months I have been listening to the coaxs fed by my ClassD amp (connected directly to my Havana DAC, volume control by MPD). I work from home so I have music going much of the time.

I started listening to the buffer yesterday and now have about 13 hrs on it, so it has not fully broken in. What I am hearing is no self noise, the buffer does not add any noise that I can detect (on 97dB speakers), this has always been a concern of mine and one of the reasons I have always been a minimalist when it comes to equipment, less has always equaled better to me, not any more! I feel the buffer is alowing me to hear more of what is on the recording although for me this seems counter-intuitive. I hesitate to write the following because it is said in nearly all audio equipment reviews, I am hearing things I have not heard before in tracks I am very familiar with, subtle things that I should have heard long ago, for instance a quietly struck bell near the end of Madman Across the Water, I have heard this track hundreds of times over the past 30+ years, but I have never noticed this before. I am hearing better separation, definition and tonality of individual instruments, the piano sounds more like a piano than any other system I have ever heard (not that I get to hear many different systems). I have not heard much difference in the male voice but some female voices have taken on a more sultry presentation.

This is what I have heard so far. Of course I hoped to hear improvements but I did not know where/if they would show themselves, I am excited to hear what further changes occur as this unit breaks in, I know the platinum bypass caps can really smooth out over time as they did in the V-1 crossover.

Yes, I am gushing about my new project/aquisition, but I am very pleased with the outcome and can't wait to hear the system once the V-1s are complete.

Great job Gary, thanks for offering this great kit!

Best,
Ed

edit: I should mention for others that may want to use this buffer with the ClassD amps that when stacked on top of my unshielded ClassD amp I picked up a hum, moving the buffer next to the amp solved this issue.

ebag4 · « **Reply #292 on:** 27 Apr 2010, 08:06 pm »

Gary,
It appears I am getting about 7.5 hrs out of a 5ah battery using the stock tube (6H1N-EB). Can you tell me where this tubes falls in efficiency as compared to other typical tubes? Also, will a 12V tube last longer since we aren't dissipating energy as heat in the voltage regulator?

Thanks,
Ed

gld · « **Reply #293 on:** 27 Apr 2010, 09:21 pm »

Hey Ed That 6N1P is the highest filament current out of all the tubes coming in at close to 1 amp. A 12AX7 uses 150 milliamps and I use a 6DJ8 that uses about 360 ma. 12 volt tubes will have a lesser filament current than most 6 volt tubes, and yes when you use a 12 volt tube the reg is doing nothing.
Gary

dmatt · « **Reply #294 on:** 27 Apr 2010, 11:08 pm »

This may come across as a silly question:

If all I will use are one set of inputs and both outputs, is there any sonic benefit to leaving the add'l RCA connectors (inputs and record out) off the board and skipping the input selector switch?

I would have to redo the bullet-proof common ground for the RCAs since I am using fewer RCAs, but I can manage that.

Just wondering ...

Thanks,

David

dnewcomer · « **Reply #295 on:** 27 Apr 2010, 11:37 pm »

Gary,
Can you recommend a pre-startup test plan? Things that can be checked using a mmeter.

gld · « **Reply #296 on:** 28 Apr 2010, 12:18 am »

It's doable. IMO I cannot see any sonic differences. While the unit is being used there is only 1 input selected at a time, all others are not there. The traces going to the jacks and to the relays are pure copper and very large and short so I really cannot see any differences there. You need the turn on delay/mute circuit for normal operation. The selector only carries 12 volts so there is no concern of audio on those wires.
gary

gld · « **Reply #297 on:** 28 Apr 2010, 12:24 am »

dnewcomer I have tested all of the potted modules before shipping them. The only thing I can really recommend is to be sure of the polarity of all the power and grounds are correct and check the wiring to be sure it's correct. Make sure to check the boards for solder bridges and any other problem. Be sure all components are in correctly, (diodes and such).
You can turn it on and it WILL work!

Gary

dmatt · « **Reply #298 on:** 28 Apr 2010, 02:39 am »

Thanks for the response, Gary.

Quote

It's doable. IMO I cannot see any sonic differences. While the unit is being used there is only 1 input selected at a time, all others are not there. The traces going to the jacks and to the relays are pure copper and very large and short so I really cannot see any differences there. You need the turn on delay/mute circuit for normal operation. The selector only carries 12 volts so there is no concern of audio on those wires.
gary

Given that you probably have better ears than I do (and certainly more experience), I will build the buffer the way it came. Less chance of screwing it up too.

David

Mariusz · « **Reply #299 on:** 28 Apr 2010, 03:16 am »

Sorry for late reply. (Family emergency)
Did not have too much free time on my hands today.
I did however, some dry fitting today and tried to discover possibility of "tube through top cover" approach.
Without further ado, here are some pictures (from iphone

):

First - use larger bit for ins/outs. Do not drill right through. Leave 1/8 thickness of the material.

Use smaller bit (RCA size) and continue drilling through. Use the center mark from previous bit as guide.

Dry fit, make sure it goes in and out smoothly. Use long-nose pliers to tightening the nuts. (that did not sound too good)

Now, do the same for both switches and volume pot - next 3 pics. (single hole with counter sink for remote receiver next to the volume pot)

And few shots of the tube pot riser clear-bridge, overall view (not finished yet), tube cutout.......

Now, I need few more parts and try to connect all boards, pots and switches, hook up the battery and hopefully listen to some fine music.