Dodd Preamp - Capacitor Upgrade Question

jtwrace · « **Reply #20 on:** 12 Feb 2010, 02:37 pm »

Any updates on this?

GregC · « **Reply #21 on:** 12 Feb 2010, 08:20 pm »

Quote from: jtwrace on 12 Feb 2010, 02:37 pm

Any updates on this?

I decided that the risk of coloring the sound (or creating a "house" sound) is not worth the time and expense. Also, I will have to wait several hundred hours before I can render final judgement. I love the preamp "as-is" so I would hate to have it just sound different but not better. I read every capacitor thread I could find but that does not tell the final story "in my system."

jtwrace · « **Reply #22 on:** 12 Feb 2010, 08:24 pm »

Ok.

I'm going with the platinum bypass on my Dodd Buffer. We'll see...

GregC · « **Reply #23 on:** 12 Feb 2010, 08:27 pm »

Quote from: jtwrace on 12 Feb 2010, 08:24 pm

Ok.

I'm going with the platinum bypass on my Dodd Buffer. We'll see...

The Sonicap Platinum? My preamp has Sonicaps with low value Sonicap Platinums for the bypass.

jtwrace · « **Reply #24 on:** 12 Feb 2010, 08:28 pm »

Quote from: GregC on 12 Feb 2010, 08:27 pm

The Sonicap Platinum? My preamp has Sonicaps with low value Sonicap Platinums for the bypass.

Yes, the buffer doesn't come with any bypass caps...so we're going to do it! It will use 3.3uf like yours.

Danny Richie · « **Reply #25 on:** 12 Feb 2010, 08:29 pm »

There is no coloration or house sound created by adding Sonicap Platinums. A bit the opposite actually. The faster discharge rate Platinum eliminates coloration. It adds a little more space between notes as it discharges the stored energy of the larger cap faster. Think of it as a greater sense of low level details.

HAL · « **Reply #26 on:** 12 Feb 2010, 08:30 pm »

The Sonicap Platinum Bypass sound wonderful in the Dodd Battery Preamp and N2X here!

jtwrace · « **Reply #27 on:** 12 Feb 2010, 08:31 pm »

Quote from: HAL on 12 Feb 2010, 08:30 pm

The Sonicap Platinum Bypass sound wonderful in the Dodd Battery Preamp and N2X here!

I'm looking forward to it

GregC · « **Reply #28 on:** 12 Feb 2010, 08:32 pm »

So if I swapped out my Sonicap/Sonicap Platinums for just Platinums I would get more of the goodness?

Danny Richie · « **Reply #29 on:** 12 Feb 2010, 08:43 pm »

Quote

So if I swapped out my Sonicap/Sonicap Platinums for just Platinums I would get more of the goodness?

That would be nice. Anything bigger than a 1.0uF in a Sonicap Platinum is a custom order. And the 1.0's are $98 each. I think Jeff had some 3.0's made up at one time. I can get a price on them if you like.

jtwrace · « **Reply #30 on:** 12 Feb 2010, 08:45 pm »

Quote from: Danny on 12 Feb 2010, 08:43 pm

That would be nice. Anything bigger than a 1.0uF in a Sonicap Platinum is a custom order. And the 1.0's are $98 each. I think Jeff had some 3.0's made up at one time. I can get a price on them if you like.

Ooooh. Think that's what I'm doing! Sending Gary an email now.

GregC · « **Reply #31 on:** 12 Feb 2010, 08:47 pm »

Quote from: jtwrace on 12 Feb 2010, 08:45 pm

That's what I'm doing! Sending Gary an email now.

Could they be made as 3.3 for a direct replacement for my existing caps? Would they be better than V-Caps?

jtwrace · « **Reply #32 on:** 12 Feb 2010, 08:49 pm »

Quote from: GregC on 12 Feb 2010, 08:47 pm

Could they be made as 3.3 for a direct replacement for my existing caps? Would they be better than V-Caps?

dunno. Let's see what Gary / Danny say.

jtwrace · « **Reply #33 on:** 12 Feb 2010, 08:55 pm »

I hate waiting....

Danny Richie · « **Reply #34 on:** 12 Feb 2010, 09:04 pm »

Okay, I just spoke with Jeff at Sonic Craft about it and the application.

What will sound the best is using as small of a cap as possible without being too small and limiting bandwidth.

Gary has to put a cap in there that will work well for most all applications, and he does.

The real question is, what is the input impedance of your amp? Or if you drive more than one amp (like a main amp and a sub amp) then what is the input impedance of each one?

The higher the input impedance, the smaller the cap that can be used. You might can even use a 1.0uF value. If your amp has a lower input impedance then a larger value will need to be used.

So what do have?

Quote

Would they be better than V-Caps?

Simple answer, Yes!

jtwrace · « **Reply #35 on:** 12 Feb 2010, 09:24 pm »

My mono blocks are 100k imput impedance. I also use two Rythmik sub amps. All of this comes out of an Ashly 3.24CL active crossover.

My active crossover is 18k input. Specs shown here: http://www.ashly.com/324clspecs.html

GregC · « **Reply #36 on:** 12 Feb 2010, 09:28 pm »

Quote from: Danny on 12 Feb 2010, 09:04 pm

Okay, I just spoke with Jeff at Sonic Craft about it and the application.

What will sound the best is using as small of a cap as possible without being too small and limiting bandwidth.

Gary has to put a cap in there that will work well for most all applications, and he does.

The real question is, what is the input impedance of your amp? Or if you drive more than one amp (like a main amp and a sub amp) then what is the input impedance of each one?

The higher the input impedance, the smaller the cap that can be used. You might can even use a 1.0uF value. If your amp has a lower input impedance then a larger value will need to be used.

So what do have?

Simple answer, Yes!

Thanks for the update Danny. I am sorry I missed you and Gary at RMAF this year. I used to live 15 minutes from the venue but I moved back to CA to work for my former employer. I am a CA native so I am used to the higher cost of living.

I already have the Sonicaps and Platinums for the bypass. I am not sure of the value of the Platinum (I think it is something like 0.1UF) or the input impedence since that is Gary’s domain. I would like to have the largest possible value (up to 3.3UF) that is possible. I have one of the original 20 preamps from Gary.

GregC · « **Reply #37 on:** 12 Feb 2010, 09:42 pm »

Danny,

I re-read your posting and I did not answer your question. I have a Behringer DCX 2496 active crossover and I read the manual and it says the input impedence is 20K Ohms.

Greg

jtwrace · « **Reply #38 on:** 12 Feb 2010, 11:09 pm »

I added my crossover info as well.

Danny Richie · « **Reply #39 on:** 12 Feb 2010, 11:39 pm »

Bummer for you guys.

If all you needed was to drive 100k ohms then a 1uF cap would do it.

Adding the Rythmik plate amp is adding a 30k ohm device. That makes 23k ohms. So now you need a 3uF value.

If your electronic crossover is as low as 18k ohms then you could even go to a 4uF value.

Greg, your 20k ohm crossover also needs at least a 3uF.

Sonic Craft is out of 3uF Platinum's but he does have a 4uF value on hand, and that will work fine for both of you if they are not so big as to not have room to mount them.

The 4uF Platinum's are $230 each.

Gary said that he'd stick with by-pass the regular Sonicaps with the smaller Platinum and try rolling in some different tubes. The tubes can make more difference than the caps.

There is also no one tube that is the best. Each type can sound a little one way or another and each person my like one over the other for their application.