Preampless - DIY Kit?

audiocr381ve

Well, I'm in the middle of a move and needed some extra dough, so I was forced to let my new preamp go. It was just enough funds to cover what we needed, but now I'm preampless...again.

I'm wondering if their is a DIY preamp kit out there that sounds excellent and can hold me over until I work up the funds to buy something else. I'd need 2 inputs and don't need a remote. Is their anything out there that can sound good on a budget ($100ish)?

FTGV

If the passive mode in the 750 worked for you you could simply try a 10k Alps or Noble pot http://www.dhgate.com/2x-10k-stereo-pcb-potentiometer-pots-for/r-ff8080812ebde44b012ed74484032d63.html in one of these Hammond cases http://www.hammondmfg.com/1455ptbla.htm and a toggle switch for source selection.

[Deleted User]

Suggestion - I just bought an older (80's maybe) Hafler stereo pre-amp off of Ebay for about 100 clams + shipping. I notice that there also upgrade kits available in case you want to modify it. As I said, only a suggestion. Cheers. :cool:

bikerboy

Thats funny because I bought your preamp making you preampless but now I have 3 including the Adcom. I have a passive LDR preamp I made from a kit called a Lighter note. It is similar to the Lightspeed preamps. I also have a Superphon preamp that has 3 total inputs, one is phono. The Lighter note is an excellent preamp. If you can wait I will compare it to the Adcom. It should sound as good or better. Only one input because it sounds better that way. I do have input switching for it if needed. PM me if you are interested.

zingo

I don't remember exactly how much the Luminous Audio Axiom I, but around $100. It's a basic passive pre, but tuned to your system based on efficiency of your speakers, input impedance of your power amp, input sensitivity of your power amp, and output voltage of your source. That translated into great synergy for my system. I now have the new Axiom II, and it's sexy... :redface:

audiocr381ve

FTGV
If the passive mode in the 750 worked for you you could simply try a 10k Alps or Noble pot http://www.dhgate.com/2x-10k-stereo-...484032d63.html in one of these Hammond cases http://www.hammondmfg.com/1455ptbla.htm and a toggle switch for source selection.

I wouldn't have a clue on how to assemble it. Do you have more info on what it would take? I am interested.

bikerboy
Thats funny because I bought your preamp making you preampless but now I have 3 including the Adcom. I have a passive LDR preamp I made from a kit called a Lighter note. It is similar to the Lightspeed preamps. I also have a Superphon preamp that has 3 total inputs, one is phono. The Lighter note is an excellent preamp. If you can wait I will compare it to the Adcom. It should sound as good or better. Only one input because it sounds better that way. I do have input switching for it if needed. PM me if you are interested.

I'd love to hear a comparison. I just found your thread where you're sharing the build and your thoughts. You really had some great things to say about it. That chassis has to go though! :P I'd love more info.

nap
Suggestion - I just bought an older (80's maybe) Hafler stereo pre-amp off of Ebay for about 100 clams + shipping. I notice that there also upgrade kits available in case you want to modify it. As I said, only a suggestion. Cheers.

Are you thinking about letting it go or suggesting I buy an old Hafler and find an upgrade kit? It doesn't sound like a bad idea. Especially if it has a phono section.

zingo
I don't remember exactly how much the Luminous Audio Axiom I, but around $100. It's a basic passive pre, but tuned to your system based on efficiency of your speakers, input impedance of your power amp, input sensitivity of your power amp, and output voltage of your source. That translated into great synergy for my system. I now have the new Axiom II, and it's sexy...

Just checked out the website. Those look really nice. I don't like the fact that I'd have to send it in to get recalibrated for any system changes, BUT, it is pretty rad that you CAN do that. I've never heard of a preamp that can do that.

Anybody have experience with the Pass B-1 preamp kit? That one looks interesting too.

heiney9

zingo wrote: »

I don't remember exactly how much the Luminous Audio Axiom I, but around $100. It's a basic passive pre, but tuned to your system based on efficiency of your speakers, input impedance of your power amp, input sensitivity of your power amp, and output voltage of your source. That translated into great synergy for my system. I now have the new Axiom II, and it's sexy... :redface:

He could never get one of these because he changes gear like the rest of us change underwear. :cheesygrin:

H9

audiocr381ve

heiney9 wrote: »

He could never get one of these because he changes gear like the rest of us change underwear. :cheesygrin:

H9

You're a ball busting **** ya know that?

:P

heiney9

audiocr381ve wrote: »

You're a ball busting **** ya know that?

:P

You make it soooooooooo easy:cheesygrin::twisted:

audiocr381ve

heiney9 wrote: »

You make it soooooooooo easy:cheesygrin::twisted:

hahahaha

heiney9

DIY like Fred suggested is probably the cheaper way to go. No all passives are NOT created equal, so be sure to do your research. Also realize once you do that, everything you listen to will be passive. Only speaking from my experience and preference's, I wouldn't want to be that pigeon holed. I listen to all sorts of music styles and recordings and 100% Passive doesn't cut it for me.

Plus, I really agree with this quote, NP being my favorite designer Nelson Pass (the entire interview can be read here):

AR: What's your position on passive versus active preamps?

NP: You'd think that a minimalist switch and variable resistor in a box would be as good or better than active stages, but often it is not.

Some of the issues are well understood; for instance if the resistance value of the potentiometer is low, the source can have bass issues due to the output coupling capacitance and higher distortion due to greater load current. At the other extreme, if the resistance is too high it can create distortion and high frequency issues by presenting a high source impedance to the power amp.

Then there are things that don't show up in the usual measurements and we simply observe that the active circuit sounds better than the passive.

I file these under "How About That".

audiocr381ve

heiney9 wrote: »

DIY like Fred suggested is probably the cheaper way to go. No all passives are NOT created equal, so be sure to do your research. Also realize once you do that, everything you listen to will be passive. Only speaking from my experience and preference's, I wouldn't want to be that pigeon holed. I listen to all sorts of music styles and recordings and 100% Passive doesn't cut it for me.

Plus, I really agree with this quote, NP being my favorite designer Nelson Pass (the entire interview can be read here):

AR: What's your position on passive versus active preamps?

NP: You'd think that a minimalist switch and variable resistor in a box would be as good or better than active stages, but often it is not.

Some of the issues are well understood; for instance if the resistance value of the potentiometer is low, the source can have bass issues due to the output coupling capacitance and higher distortion due to greater load current. At the other extreme, if the resistance is too high it can create distortion and high frequency issues by presenting a high source impedance to the power amp.

Then there are things that don't show up in the usual measurements and we simply observe that the active circuit sounds better than the passive.

I file these under "How About That".

That's the kind of stuff I was looking to learn through this whole process. Great quote. I was going to ask what the advantages of passive or active would be, but that pretty much laid it out. With the GFP-750 I enjoyed both passive and active modes equally. Passive sounded like it had a touch more transparency with a blacker background, but active had a great sound to it too.

For now, I just want to be able to play some records and use my CDP, so I'm sure one of these inexpensive DIY builds would do it for me.

heiney9

The flexibility of the 750 is what I like. I admit I use the Dared more than the 750 in passive or active, but I like the choice, because in the end you are at the mercy of the recording and the ability to use all 3 allows me to get the sound I want/like.

Over the weekend I did have a chance to listen to the 750 on it's own. Didn't feel like messing with the tubes, and it still sounds great.

H9

FTGV

audiocr381ve wrote: »

I wouldn't have a clue on how to assemble it. Do you have more info on what it would take? I am interested.

Not much to it really.Simply drill a few holes to mount int /out RCA con's,pot and toggle switch then solder a few wires. Using one of the Alps pot previously linked to or better yet find a Noble.The 10K value I suggested is a good compromise value as to input /output impedances.

Anybody have experience with the Pass B-1 preamp kit?

I have a blank PC board for an improved version that I've been threatening to build for over 2yrs.Maybe someday.

heiney9

The Pass B-1 is supposed to be fantastic. Plus there is lots and lots of info at DIY if you are apprehensive.

H9

audiocr381ve

heiney9 wrote: »

The Pass B-1 is supposed to be fantastic. Plus there is lots and lots of info at DIY if you are apprehensive.

H9

Maybe I'll try Freds AND the B-1. It's hard finding solid information on what I'd need for it. Is their a kit for purchase out there?

heiney9

It seems like someone like Peter Daniels made some boards and I know at one time you could buy them direct from Pass DIY

For $40 I might get the boards and J-fet kit and build one for the heck of it.

H9

FTGV

audiocr381ve wrote: »

It's hard finding solid information on what I'd need for it. Is their a kit for purchase out there?

There is periodic group buys at DIYaudio for the direct coupled(no coupling caps)shunt regulated versions.You can buy just the the PC board or it and most of the hard to source parts like the fet's etc.As Brock mentioned Pass also sells the PC board and fet's for the original basic capacitively coupled ,single supply version.

FTGV

Here is one I built (originally) with this Alps pot(first pic) http://www.partsconnexion.com/controls_pot_alps.html and this Hammond case.http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=ca&KeyWords=hm973-nd&x=23&y=14


It is just a straight in/out attenuator but if you need to switch between two sources you can add a good DPDT toggle switch and another pair of RCA inputs.




I see this guy is still around and has the Noble AP25 in 10k (see page 14).http://www.pearl-hifi.com/04_Links_Dealers/Dealers_Catalogues/M_Percy_Catalogue.pdf

I have found these Nobles to have tighter tracking than the Alps between sections.

audiocr381ve

Thanks for the links Fred, although I made the decision to get a little more involved and try the Pass B1 Buffer. It looks like it would be a more rewarding project. Have you done one of these Fred?

FTGV

audiocr381ve wrote: »

Have you done one of these Fred?

No,as I mention in post#14 I have a PC board just have not bothered to build it yet.The pre I have been using the last few years is also pulled from a Pass article and I'm in no hurry to replace it.

Good luck in your endevour.

audiocr381ve

FTGV wrote: »

No,as I mention in post#14 I have a PC board just have not bothered to build it yet.The pre I have been using the last few years is also pulled from a Pass article and I'm in no hurry to replace it.

Good luck in your endevour.

Don't check out to soon!

FTGV

audiocr381ve wrote: »

Don't check out to soon!

I'll be lurking.

audiocr381ve

FTGV wrote: »

I'll be lurking.

Hehe

lanchile

Read here about it.
http://www.google.com/url?sa=t&rct=j&q=passive%20preamp&source=web&cd=1&sqi=2&ved=0CFUQFjAA&url=http%3A%2F%2Fwww.dact.com%2Fhtml%2Fpassive_preamp.html&ei=u6FFT6eSOOHV0QHBzJjqAw&usg=AFQjCNEYMusyICI_9K7VX0s0yiyV7Ng3Jw

strider

The Store at diyaudio.com sells boards for the B1 now. I thought the Jfets were getting difficult to source for some reason, though I may be mistaken. There's a guy that goes by the screen name Blue at that forum that has had parts available in the past, may want to look him up.

The LDR based passive pre iterations seem to be popular as well, plenty of different versions. Couple of threads on Audio Circle and enough info at diyaudio to really set your mind spinning.

I bought my B1 clone from Tim Rawston when he was still building Pass clones, even built for me it was under $200. Now I've got an Aikido that I built from a kit, but it'd blow away your budget on iron alone.

maximillian

Strider, how would you compare the B1 to the Aikido? Is it the LV Aikido? I am thinking of building the LV Aikido or the B1 buffer and trying to decide between the two. They will be fed with a DACmagic to an Adcom SS amp to LSi9's.

Thinking of also getting one of those Chinese/Ebay selector boards with Alps remote controlled pots. I would need a HT passthrough that can be selected with the selector PCB.

strider

I built the Aikido Octal All in One kit, has the power supply on the same board as the gain stages.


http://glass-ware.stores.yahoo.net/ocalcukit.html

It's out of my system at the moment so I can redo the volume pot and some wiring. Set it up to run 6SN7 tubes, I'd like to re-do it to run 12SN7 tubes as they're less expensive and there are more available.

The Aikido build was much more complicated and expensive then a B1. Voltages are way higher so you'd need to take that into account as well. Far as sound goes, I don't know if I should make a comment. Reason being is that I think that there are improvements to be made with the way I built the thing that could effect the way it performs. I do prefer the B1 in my system, but I've also got a Pass DIY amp behind it, so there's something to be said for the synergy of the combination.

In your system I'd be willing to bet the tubes may be a nice way to go...

maximillian wrote: »

Strider, how would you compare the B1 to the Aikido? Is it the LV Aikido? I am thinking of building the LV Aikido or the B1 buffer and trying to decide between the two. They will be fed with a DACmagic to an Adcom SS amp to LSi9's.

Thinking of also getting one of those Chinese/Ebay selector boards with Alps remote controlled pots. I would need a HT passthrough that can be selected with the selector PCB.