Hammond Chokes w/ Quickie - Cheap and Worthwhile!

[Koda]

Thanks Paul! Now why didn't I think of that... an easy fix is sometime the least obvious to me.

It did just what you thought it would, now I just need to shuffle some gear around!
 

[Dr. Toobz]

To answer some earlier questions, the chokes are Hammond 156C. I bought them from Angela Instruments for $14 each.

Also, I'm not getting even a trace of hum. Right now, the chokes are just "hanging out" underneath the Quickie in the temporary cardboard box I've been using as a base while I finish the wooden one. I don't have them near (or aligned with) the OPT's to avoid coupling any noise into the signal. I also don't have the Quickie near any power transformers or the like.

I've been playing some Eric Dolphy and Sonny Rollins this evening and it sounds great! I should have a photo or two to post in the next few days.

[Grainger49]

Be bold, post the cardboard box first!

[booangler]

To answer some earlier questions, the chokes are Hammond 156C. I bought them from Angela Instruments for $14 each.

Dr T,

Thanks, I ordered mine today from RadioDaze. Can not wait to try them out.

Cheers,

Alan

[booangler]

Hi all,

My Hammond 156C chokes arrived on Tuesday, installed them about 5 minutes ago. I took my time with the modification. I wanted the chokes to look like they belonged where I placed them. As stated earlier in the post they fit perfectly on the mounting screws for the D cells.

This made a number of changes to my system. Usually my first test materiel is Dire Straits LP "Brothers in Arms" however today I picked The Derek Trucks Band CD "Songlines" The first thing I noticed was a dramatic increase in the base response in Crow Jane. I was not prepared for the biggest change! When the first Derek Trucks guitar solo on Crow Jane I was blown away at the increased depth of his guitar.  All I can say is, WOW. This modification is the best $26 I have spent in a while. Do it you will not be disappointed!

Three cheers to Dr. Toobz for this brilliant modification. 

Cheers,

Alan

[Len]

Hi all,

My Hammond 156C chokes ... fit perfectly on the mounting screws for the D cells.

This made a ... dramatic increase in the base response ...
Alan

Thanks for the info! Since my first Quickie is being used for a low pass filter, bass is important! I'll be ordering a pair today.

Thanks also for the mounting tip.

[Dr. Toobz]

Three cheers to Dr. Toobz for this brilliant modification. 

Cheers,

Alan

I can't take any credit for this mod - at least one other member thought of it first on the old forum (I can't remember who, though). I actually was looking to build CCS's for the Quickie and stumbled upon a mention of the Hammond chokes and the possibility of using them to load the plates. In any case, they definitely are worth the money and bring the Quickie to another level!

[booangler]

Dr. Toobz,

Thanks for the update, I'll try and find the original post and give proper credit.

Alan

[Len]

I can't take any credit for this mod - at least one other member thought of it first on the old forum (I can't remember who, though). I actually was looking to build CCS's for the Quickie and stumbled upon a mention of the Hammond chokes and the possibility of using them to load the plates. In any case, they definitely are worth the money and bring the Quickie to another level!

I'm pretty sure it was DynaSaur (hey, that rhymes).

I'm glad you guys like the mod. I ordered them today. Then I got the Quickie running tonight as a low pass. It is stunning. I was starting to regret ordering the chokes, because I figured the low end couldn't get any better. I hope to post results of the choke upgrade next weekend.

[booangler]

I can't take any credit for this mod - at least one other member thought of it first on the old forum (I can't remember who, though). I actually was looking to build CCS's for the Quickie and stumbled upon a mention of the Hammond chokes and the possibility of using them to load the plates. In any case, they definitely are worth the money and bring the Quickie to another level!

Since I found different post author suggesting the Hammond Chokes, I will simply say this. Who every suggested the idea, it is a great upgrade. I thank you!

Sincerely,

Alan

[induna]

I'm another happy user of this mod. It is incredibly easy to do (you don't even have to drill any holes!), and it increases gain, bass authority, and increases the amps overall resolution (at least to my ears).

I mounted them as follows:

1. Replace the four #4-3/8" screws holding the D cell battery holders with #4-3/4" screws. Use the existing nut and tighten according the manual.

2. Place 1 small rubber grommet on each screw (poor man's standoff).

3. Place the chokes on the screws on top of the grommets.

4. Place #4 washers on top of the choke tabs and snug down with 4 #4 nuts.

5. Remove the existing 4K plate load resistors.

6. Solder the choke leads exactly the same way the resistors were soldered.

It took about 20 minutes total including the soldering.

[Dr. Toobz]

Sort of an update here - since moving my Quickie to use as a linestage in my main system (between the DAC/Seduction and S.E.X. amp), the Hammonds are picking up some hum when the pots are turned all the way up. Now granted, I never turn the pots up very high, as there's plenty of gain, but I don't like the idea of any added noise to my signal, however small. (When used as a headphone amp with my iMac, the Quickie was dead quiet - but this was likely due to it being the only electronic device on the desk). Since I want my chain to have the same inky-black background as the S.E.X. amp when used alone, I ordered the PJCSS and will be swapping that in once it arrives. That should take out all of the "iron" between my components and the S.E.X. amp, as I already did surgery to remove the Specos and accompanying headphone circuitry some time ago.

If anybody is interested in buying my chokes, I'd sell them for a decent price (perhaps $20, including shipping, for the pair?).

[Len]

Those are nice chokes for other projects. You can throw them in a preamp instead of plate resistors to check out the sound.

[Dr. Toobz]

I had thought of that, actually. I already have a box of tube-related parts (in addition to my ongoing junk boxes of assorted resistors, caps, etc). from my various Bottlehead projects and upgrades, so maybe a homemade amp is the next place to go. I may eventually try out designing something simple on my own, though I'm a psychologist, not an electrical engineer.....

[Dyna Saur]

I'm probably not the only one who thought of this mod, but here is my posting "lifted" from the old forum:

The Hammond C156C chokes are readily available from AES, Angela, etc.  Same size as the Dynaco C354 and Hammond 156R.   I measured one of my 156Cs and it has a DCR of 3460 ohms.(They're still not yet in my  "modder" Quickie)

Posted by Dyna Saur (A ) on September 25, 2009 at 18:48:32
In Reply to: RE: Transformers posted by Paul Joppa on September 25, 2009 at 13:45:03:


Hammond has a couple of high inductance, low current chokes which may be usable as suitable plate loads for the Quickie's 3S4s.

155C, 60H, 8 mA, DCR = 2750 ohms, about $14 each.

156C, 150H, 8 mA, DCR = 3700 ohms, about $15 each.

Since these are both below the nominal 4.02K plate resistor value, one could insert an LED in series between the B+ line and the choke's "hot" side, for a pilot light, or tube activity indicator. Depending on the LED color, it will introduce between 1.6 and 3.6VDC voltage drop, which is pretty much minimal. Don't connect the LED on the plate side, it could introduce some unwanted noise into the equation.

Now, these inductors aren't going to be of Magnequest quality, but at the cheap prices, they may be a good deal for this application, along with the SPECO matching trannies. I'd SWAG that 2.2 to 3.3 uF would be a good coupling cap value , into the reflected 4K ohms. Voltage rating could be as low as 100V, but I'd probably go with 250V (basically because I have lots of such caps in my stockpile).

This topic alone has intrigues me to the point that I put in an order for not just one, but two, Quickies ;-)

Being one who can never leave "well enough" alone, these Quickies are a very interesting and readily modifiable project, which I just can't resist.. A little research indicates that 1S4s can be used with a simple re-conenction of the filament leads (use pins 1 and 7, leave 5 open). Just becuzz....

All of this talk of "quickies" reminds me of a very old, rude joke involving a pastor and a nun, but since this is a polite family-oriented site, I won't post it here ;-)

/ed B in NC