Dodd Buffer

ebag4 · « **Reply #200 on:** 18 Apr 2011, 05:11 pm »

Quote from: NeilT on 18 Apr 2011, 04:56 pm

Your faceplate looks very good and thank you for all the pics.
I am thinking external bats are the way to go?

Neil

Neil,
I ran a 5AH gel cell in the buffer for a while. My system is in my home office so it is on for 8-10 hours almost daily. With the 5751 tube Iwas getting a full days playing, when I tried some more current hungry tubes the battery was not getting it done. The battery was not new so it could have been getting weak. If you plan to run the 6H30 for extended periods I don't think the 5AH will cut it. It really depends on your use of the buffer.

Best,
Ed

NeilT · « **Reply #201 on:** 18 Apr 2011, 05:22 pm »

Quote from: ebag4 on 18 Apr 2011, 05:11 pm

Neil,
I ran a 5AH gel cell in the buffer for a while. My system is in my home office so it is on for 8-10 hours almost daily. With the 5751 tube Iwas getting a full days playing, when I tried some more current hungry tubes the battery was not getting it done. The battery was not new so it could have been getting weak. If you plan to run the 6H30 for extended periods I don't think the 5AH will cut it. It really depends on your use of the buffer.

Best,
Ed

Sounds good and thanks for the info.

Neil

TrungT · « **Reply #202 on:** 18 Apr 2011, 05:25 pm »

6H30 tube have 1A draw, so 10AH batter is much better with C-Tek 3300 charger.
Plugged in and forget about it.

And 6H30DR is the way it goes.

NeilT · « **Reply #203 on:** 18 Apr 2011, 05:30 pm »

Quote from: TrungT on 18 Apr 2011, 05:25 pm

6H30 tube have 1A draw, so 10AH batter is much better with C-Tek 3300 charger.
Plugged in and forget about it.
And 6H30DR is the way it goes.

The 6H30DR is better than the stock tube?
Is this what is called the "super tube"?
Where can these be purchased / how much?

Thanks
Neil

NeilT · « **Reply #204 on:** 18 Apr 2011, 06:22 pm »

Just got off the phone with Gary, he sounds great, spirits up.
Pulled the trigger, Kit is in the mail with upgraded RCA's and remote.

Thanks for all the feedback.

Neil

dBe · « **Reply #205 on:** 18 Apr 2011, 07:41 pm »

Quote from: ebag4 on 18 Apr 2011, 05:05 pm

Dave, I am not sure what to tell you because I didn't come up with the value myself. The response above was a quote from the PM Danny sent me, here is a pic of the cap he sent me installed in the buffer.

If you learn it should be something different please let me know. It is difficult for me to hear the difference due to the coax of the V1 being hi-passed at 200 Hz anyway, so the advantage gained with the hi-pass cap in the Dodd is just to relieve the amp from playing the low bass.

Best,
Ed

Gotcha

Thanks.

Dave

gld · « **Reply #206 on:** 18 Apr 2011, 08:08 pm »

.047 uf it is correct!
Gary

dBe · « **Reply #207 on:** 18 Apr 2011, 08:33 pm »

Quote from: gld on 18 Apr 2011, 08:08 pm

.047 uf it is correct!
Gary

Great to see you here

Thanks,

Dave

cujobob · « **Reply #208 on:** 19 Apr 2011, 05:39 pm »

I'm curious.... what would the Dodd Buffer be able to do that passive attenuators could not? (Other than source switching)

I'm picking up a Buffer and just curious as to how it will compare to what I currently use. I had a MAD Line 2A preamp before using the attenuators and loved it though gain was never needed with my Mcalister tube power amp.

Also, I'm putting the battery power together myself though I'm not much of a DIY guy... is there any straightforward info on how to do this or pretty common sensical (if that's even a word

)?

S Clark · « **Reply #209 on:** 19 Apr 2011, 06:03 pm »

Quote from: cujobob on 19 Apr 2011, 05:39 pm

I'm curious.... what would the Dodd Buffer be able to do that passive attenuators could not? (Other than source switching)

I'm picking up a Buffer and just curious as to how it will compare to what I currently use. I had a MAD Line 2A preamp before using the attenuators and loved it though gain was never needed with my Mcalister tube power amp.

Also, I'm putting the battery power together myself though I'm not much of a DIY guy... is there any straightforward info on how to do this or pretty common sensical (if that's even a word )?

The photo instructions on Gary's site are really quite easy to follow. As far as the batteries are concerned, I think that the only thing you can do wrong is to connect the battey backward- which will blow a diode (don't ask how I know

). The key thing is that anything that you can screw up the good folks here or Gary himself can help you correct.
Besides, if you get a kit and aren't happy, several of us would probably take it off your hands just to have a second buffer for a second system- though Trung may not need a 5th one.
Scott

HAL · « **Reply #210 on:** 19 Apr 2011, 06:09 pm »

Scott,
Trung and I have rewired our protection diode circuit in a way that I think will pervent that from happening. It is very simple.

If it is ok with Gary, I will post the mod.

HAL · « **Reply #211 on:** 19 Apr 2011, 06:18 pm »

Quote from: cujobob on 19 Apr 2011, 05:39 pm

I'm curious.... what would the Dodd Buffer be able to do that passive attenuators could not? (Other than source switching)

I'm picking up a Buffer and just curious as to how it will compare to what I currently use. I had a MAD Line 2A preamp before using the attenuators and loved it though gain was never needed with my Mcalister tube power amp.

Also, I'm putting the battery power together myself though I'm not much of a DIY guy... is there any straightforward info on how to do this or pretty common sensical (if that's even a word )?

The advantage of using a buffered volume control over just a passive attenuator is having high input impedance and low output impedance. This is what the buffer adds.

A typical passive attenuator should have very little cable capacitance loading the device to prevent HF rolloff. Some folks make their passive attenuators so they plug directly into the amp to fully minimize any loading capacitance. This is not an issue with a buffer after your attenuator. The output impedance is low and can drive normal cable lengths.

S Clark · « **Reply #212 on:** 19 Apr 2011, 06:21 pm »

Quote from: HAL on 19 Apr 2011, 06:09 pm

Scott,
Trung and I have rewired our protection diode circuit in a way that I think will pervent that from happening. It is very simple.

If it is ok with Gary, I will post the mod.

Thanks, Rich. I'll be watching for it, or send me a PM.

Scott

HAL · « **Reply #213 on:** 19 Apr 2011, 06:29 pm »

Scott,
Will do.

gld · « **Reply #214 on:** 19 Apr 2011, 07:25 pm »

go ahead Rich it is fine with me.
gary

HAL · « **Reply #215 on:** 19 Apr 2011, 07:39 pm »

Ok, here is my idea for the diode protection circuit.

The diode is the 6 amp unit and the fuse is the 2 amp fast blow that Gary uses in the kit. From what I have read the fuse should blow first in this circuit.

It was pretty easy to wire my buffer with this setup.

The left side of the schematic is the battery input and the right is the output to the buffer.

NeilT · « **Reply #216 on:** 20 Apr 2011, 03:30 am »

Quote from: HAL on 19 Apr 2011, 07:39 pm

Ok, here is my idea for the diode protection circuit.

The diode is the 6 amp unit and the fuse is the 2 amp fast blow that Gary uses in the kit. From what I have read the fuse should blow first in this circuit.

It was pretty easy to wire my buffer with this setup.

The left side of the schematic is the battery input and the right is the output to the buffer.

Smart, putting the 2 amp fuse in front of the 6 amp diode. Now the short circuit current has to go thru the fuse, no matter what.
Before, the fuse would never see a reversed lead condition.

Thanks for the tip Hal,

Neil

TrungT · « **Reply #217 on:** 20 Apr 2011, 04:17 am »

Thanks Hal

I just finished mod the diode on my first Dodd buffer.

Jerrin · « **Reply #218 on:** 21 Apr 2011, 04:07 pm »

Trung, have you tried any caps other than Sonicaps in your buffers?

jtwrace · « **Reply #219 on:** 21 Apr 2011, 04:13 pm »

Quote from: Jerrin on 21 Apr 2011, 04:07 pm

Trung, have you tried any caps other than Sonicaps in your buffers?

Great question. I've been curious but it sounds so darn good with the Sonic Caps bypassed with the platinums.