I bought a Audible Ilusions Modulas 2D for $400.
It is a very nice sounding preamp, especially for the money.
I am going to mod it....of course, and I am going to document all the changes and the percieved sonic differences I hear.
Later today I will post pictures of the unit bone stock.
I will perform one mod at a time in a certain order, photograph the mod and document what I hear. I am open to suggestions.
First mod will be the volume controls. The volume controls look like Alps blue, but may be something else. I ordered Dale Vishay stepped attenuators on eBay for $51 for the pair! with resistors!. Shallco 43 stepped attenuators with resistors are $348 from Michael Percy. These I am sure are the cats meow, but at the price of what the preamp almost cost me it seemed too over the top, even though I knew it would be the best volume control. I decided to do this on a budget, try to get great performance without buying the most expensive boutique parts.
Next up in mods will be power supply:
There are two sets of electrolytics that will be replaced. Since the unit was built in 1989 it probably is just good audio hygiene to replace these. I will do this in the 2 steps that are there. I will not use Black Gates which are impossible find and are not caps I like anyway, and I know I am in the minority here. Probably elna or Nichicon, or maybe some oil caps!
Next in the power supply will be the diodes, new diodes are .just faster and quieter, never a bad thing.
After the power supply I will look at some of the coupling caps, there are a lot of them in there and good quality caps can add up quick, I will address the ones I deem important and leave the phono section alone as it is not that great anyway.
Next we will look at hookup wire, this will be replaced with Neotech cabling. I am definetly open to suggestions on this topic.
Again it will be a slow process, and one at a time, allowing the parts to burn in, I usually replace a bunch of stuff at once, and we all know that is the wrong thing to do.
Hopefully it will turn out nice, perhaps it may get ruined, but there is alot to learned along the way.
Here is alink to the volume controls I bought, the first step for great sound in a preamp.
http://www.ebay.com/itm/Dale-23-Step-Ladder-Type-Attenuator-Potentiometer-POT-Log-100K-Ohms-Mono-x-2-/221094036357?pt=US_Home_Audio_Amplifiers_Preamps&hash=item337a3b4385 (http://www.ebay.com/itm/Dale-23-Step-Ladder-Type-Attenuator-Potentiometer-POT-Log-100K-Ohms-Mono-x-2-/221094036357?pt=US_Home_Audio_Amplifiers_Preamps&hash=item337a3b4385)
Final step will be a deep cryogenic treatment of the whole unit :thumb:
Sounds like (pardon the pun) like we're in for a ride! Should be a very interesting "bang for the bu¢k" pre-amp mod/re-build that will allow everyone to learn something along the way. Keep us posted step by step, as you said you will and don't forget the photos.
Good luck and "may the flux be with you!" :thumb:
SN
Cool. The character of the AI is warm and or dark in stock form. A very colored preamp. It will be interesting to hear the sonic differences wrought by each mod.
My suggestions to consider are; Slagle chokes in the power supply, Hexfred diodes, silver hook up wire [ DH labs or Deulund ], Deulund Alexandra coupling caps,
Tubes recommended are Siemens or another brighter side of neutral tubes. Teles would be the cats meow but not cheap.
I owned the IA #A for quite some time used it with SS amps to add some lushness to them. Tubes made a huge difference with that preamp. You may just start there and then see what each mod offers in change.
Have fun a cool thing to do. BTW Penny & Giles are the so called best attenuators around.
charles
Yes. Please definitely keep us posted with all the pics to boot. I enjoy reading threads like this since I can't DIY much.
I've always been curious about refurbing/modifying the older gear.
Is this just a fun project or to prove that with refurbing older gear you can create a giant killer?
Nice preamp. This will be fun!
The attenuator steps are not very even, but the price is right. I wouldn't dip them in nitrogen though because the plastic might not take it well.
These are very nice rectifier diodes, I have used them several times with great results.
http://www.mouser.com/Search/ProductDetail.aspx?R=FFP08S60SNTUvirtualkey51210000virtualkey512-FFP08S60SNTU (http://www.mouser.com/Search/ProductDetail.aspx?R=FFP08S60SNTUvirtualkey51210000virtualkey512-FFP08S60SNTU)
Nichicon KL are good for coupling electrolytics, if electros are needed in the signal.
What voltage and capacitance are the original storage caps?
Transformer output? aa not cheap...
Some AI preamp mod ideas:
http://www.chimeralabs.com/audIllusmod.html (http://www.chimeralabs.com/audIllusmod.html)
Hey, we are moving along parallel paths Mike, I started mods on my CAT pre about a month ago. First mod was to eliminate the balance control and replace the stereo stepped pot with Khozmo mono pots, have to say it was a big jump in performance with just that one mod.
Since this CAT is circa 1990, I was also looking at the electrolytic caps as the next step. Hope we can compare notes on parts selections etc.
I will post some pics when I get back late January.
Good to know Rich, about the Nichicons. :thumb:
This is a project, a logical, laid out plan to improve a design.
Will it be a giant killer? I doubt it. Can it be improved? I think so.
This is a project just for fun, since it did not cost much it has become sacrificial, besides the preamp I really want is the Dude, which i can't afford right now(new car and braces for the kids).
Martin, we are moving in parallel lines although I might zig zag about freely with this, with your Cat i would stay within the lines, don't ruin it! Besides Ken Stevens is kind of a prima donna and thinks you should not mess with his superior designs.
Volume control is key in a preamp, most manufacturers skimp here because the really good stuff is expensive and labor intensive,but the killer volume controls are stock equipment for the DIY crowd.
Pictures coming soon, volume pots are on there way and this preamp just might become a DHT tube version, if we decide to go crazy!
(http://)
(//)
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I was looking at those Khozmo attenuators, they look very nice, and I was tempted , especially with 48 steps! but they were too expensive for this project, but I would like to try them in the future :thumb: especially since Martin is having good results with them.
Electrolytics are next on the mod list
(3) 100 uf 350 v
(3) 10,000 uf 10 v
(1) 470 uf 16 v
I am open to suggestions, what would you guys like to try?
This is what I would try
http://www.mouser.com/ProductDetail/Nichicon/UKL1C471KPD/?qs=sGAEpiMZZMtZ1n0r9vR22U0HJIc3SC%252bohOY9JOxTyFo%3d (http://www.mouser.com/ProductDetail/Nichicon/UKL1C471KPD/?qs=sGAEpiMZZMtZ1n0r9vR22U0HJIc3SC%252bohOY9JOxTyFo%3d)
http://www.mouser.com/ProductDetail/Panasonic-Electronic-Components/EEU-HD1A103/?qs=sGAEpiMZZMtZ1n0r9vR22QGha91sM8wWq6d5e4Jz2wY%3d (http://www.mouser.com/ProductDetail/Panasonic-Electronic-Components/EEU-HD1A103/?qs=sGAEpiMZZMtZ1n0r9vR22QGha91sM8wWq6d5e4Jz2wY%3d)
http://www.mouser.com/ProductDetail/Nichicon/UPW2G101MRD/?qs=sGAEpiMZZMtZ1n0r9vR22RxOeB5kHP9B6%252blgtsUaExA%3d (http://www.mouser.com/ProductDetail/Nichicon/UPW2G101MRD/?qs=sGAEpiMZZMtZ1n0r9vR22RxOeB5kHP9B6%252blgtsUaExA%3d)
Check the sizes of the cans and lead spacing.
Rich,
I will order these parts tomorrow.
BTW I like Panasonic Electrolytics :thumb:
I will post fotos of the volume controls going out and the new ones in and I will burn the steps that i like in the volume control with a cd player.
Rollo mentioned Deuland Alexander caps for the coupling caps in the signal path, these are very nice sounding caps but too expensive for this project, besides if I was to use Deuland it would be CAST as that is what they are famous for, the Alexanders are just an attempt to get more market share from the boutique market, they are rebranded Jensens, which make Deuland.
I was thinking more along the lines of the new Auricaps or maybe Dynamicaps. I am pretty familiar with the Dynamicap sound and it feels to me like it would be a good match for the AI circuit. I like Auricaps as well but I have never heard the new ones, but it seems they adressed the areas where the Auricap needed a little help(in the extremes), hopefully not at the expense of the Auricaps strength(midrange)
But coupling caps are a way off..much to do before that.
Mike
Also consider Jensen or Mundorf for the power supply.
For common parts like this digikey can ship 1st class mail, which is cheaper than mouser UPS.
For coupling I like the Jantzen Superior Z and Silver Z. They sound good and not too expensive. I avoid bypass caps.
For cheap coupling caps Vishay MKT1813 are pretty good for the money. http://www.vishay.com/docs/26013/mkt1813.pdf (http://www.vishay.com/docs/26013/mkt1813.pdf)
Quote from: richidoo on December 18, 2012, 10:21:15 PM
For common parts like this digikey can ship 1st class mail, which is cheaper than mouser UPS.
For coupling I like the Jantzen Superior Z and Silver Z. They sound good and not too expensive. I avoid bypass caps.
For cheap coupling caps Vishay MKT1813 are pretty good for the money. http://www.vishay.com/docs/26013/mkt1813.pdf (http://www.vishay.com/docs/26013/mkt1813.pdf)
Wow Rich, making 2 AM posts? :shock:
Looks like you are trying to take over my vampire shifts. 8)
We replaced Auricaps in two amps so far with the Alexandras. Only $90 for the pair [ .1 ]. Not even a contest. Just ordered Cast versions for preamp and Amps. BTW they are not re branded Jensens. Confirmed that with the distributor.
You may consider ESC caps. Lower ESR than Panasonic or Muse. When the Cyber 211 was redone Scot from S&G Custom Sound who did the work suggested them over the others. Dynamics out the ying yang.
One bit of advice if I may. When choosing tube coupling caps take in consideration what tube brand is used. You do not want to use a cap that fights the sonics of the tube. Meaning if the tubes character is say bright do not use a V-Cap. If dark do not use PIO.
Learned that lesson during the Cyber mod. If we used the NOS RCA 211 then the V-cap was a great match. Not with NOS GE 211 though. Russian PIO were a better match.
You may also consider Audio note Silver RCAs at $18 a pair. Silver over pure copper. Have fun.
charles
Quote from: rollo on December 19, 2012, 06:54:49 AM
We replaced Auricaps in two amps so far with the Alexandras. Only $90 for the pair [ .1 ]. Not even a contest. Just ordered Cast versions for preamp and Amps. BTW they are not re branded Jensens. Confirmed that with the distributor.
You may also consider Audio note Silver RCAs at $18 a pair. Silver over pure copper. Have fun.
I agree that Auricaps are nothing special. My current favorite coupling cap are Claritycap MRs, although Duelund isn't bad either. ;)
As for the RCAs mentioned above, I don't believe they're copper based...especiall at that price. Take a look at every other gold plated brass jack and they all look exactly like those mentioned, but a different color. For a copper based jack that won't break the bank, check out Vampire. http://www.soniccraft.com/products/connections/rca/chassis/vampire_cm1fcb.htm (http://www.soniccraft.com/products/connections/rca/chassis/vampire_cm1fcb.htm)
Another RCA choice to consider is CNC if you desire all copper. Me, it would be all silver with the AI.
When I purchased them parts Connection said they were silver over copper. Maybe I was misinformed. Now I have to know. :duh
charles
You might also try Jupiter HTs for coupling caps. I've used them in 2 DACS and really like them. In one they replaced Auricaps (original). Huge difference. The Jupiters are far more resolving and tonally accurate but also convey more harmonics.
They're of course much more expensive than Auricaps but much less than Dueland Alexanders.
I put these in the final stage of my Aikido's PS and they make a HUGE difference!
http://www.partsconnexion.com/capacitor_film_clarity_tc.html (http://www.partsconnexion.com/capacitor_film_clarity_tc.html)
With the larger electrolytics, maybe bypass them with some film caps, especially if they are cathode bypass caps, this makes a big difference. I used Clarity ESA caps for this in my SET amp at 1.5 uF. They make ESA caps in 250V, which are much smaller and less expensive than most film caps, good for 'lytic bypass...
Also, the AI RCAs are silver over brass, no way are they copper at that price. I've heard others say they sound good though. I went with DH labs copper RCA jacks when they were 1/2 price at partsconnexion. Unfortunately, copper RCA jacks aren't cheap.
Well I was misinformed non magnetic I guess means brass. :duh.
Mike you got me off my chair with this topic. have been thinking about eliminating the selector switch as only one input is needed. To make a long story short whoopee do do. Bypassed switch directly to board and no going back. Less noise, more clarity a bit more slam.
Next up the attenuators.The Loesh & Weisner Pre uses Elna pots. Could use a bit more flexibility in control. Those 48 step babies sound attractive. I would love to get the Penny and Giles however my bank robbing skills need work.
Interesting note in discovering silver hook up wire in the preamp. I thought I did not like silver. WRONG!!
Mike you started this thread for the AI now I'm the journey. Thanks I never would have found out the BIG difference had by removing the selector switch. Duelund hook up wire ? Penny & Giles ?? Coupling caps ??? I'm forked !! Thanks a lot. :rofl:
charles
I don't know how much room you have in your preamp but the Shallco switches with resistors for $340 from Percy sounds like the way to go for me if I have the preamp I was taking to my grave.
I have used Vampire RCA's and like them, they sound good and don't cost a lot and are high quality as well.
Pure copper....does anyone make pure copper RCA's?
Remember this is going to be a project on a budget, no Vcaps, no pure copper RCA's no, Shallco stepped attenuators and certainly no Black Gates. I want to take a decent budget preamp and see what it can become with better parts, and Charlie if I can get some Chokes in there I will because chokes are cheap, at least the Hammond ones!
Remember when I cryo this thing it just may go bye bye!! :duh
Coupling caps....that is always a good way to start a fight.
Regarding Duland...if I was to use deuland it would have to be the CAST other wise there are so many other great sounding caps to choose from.
I like Auricaps, they don't do everything but what they do well they do very well, I was wondering about the new AuricapXO's, though about giving them a try.
Modding....its back in style :thumb:
For reasonably priced coupling caps also check out Feastrex's new Urushi caps. I won a pair at RMAF and for $60 they sound really good, very neutral and clear. My RelCap PCU copper foil caps were a bit better, but for 2x the price. I'd get the Urushis over any other coupling cap near it's price range.
On a budget I think it is hard to beat Sonicaps. They are transparent and do not color the music, but they are not the choice if you are looking for something to beautify things.
Here are a few of my "personal opinions".
Coupling caps - my favorites are Clarity MR, V-Caps and Duelund. By the way, Duelund caps are made by Jensen to Frederick's specs. That's why they even say Jensen on the caps. No secrets being revealed.
I have always liked AuriCaps but now find their prices put them in competition with some other very good options. they use to be a great value.
SoniCaps are the cleanest capacitors available for the money. It you want a "no capacitor" sound at a great price, SoniCap is the one. The Gen 2 sounds very much like AuriCaps for a fraction of the cost.
Wiring- I personally like and prefer solid core Silver. Silver has gotten a bad rap over the years and my conclusion is because it wasnt given a fair shake. Like anything else in audio, the application and whole picture is more important than any one piece. A puzzle is worthless if you are missing a few pieces.
RCA jacks- Cardas is among the best in my opinion. CMC also makes some very nice pieces. Audio Note is nice but over priced. WBT.... Way over priced but another great product.
Power supply caps- prefer poly whenever possible. The Panasonic ED is my preferred electrolytic.
When changing capacitors in the power supply, an all too often overlooked but critical aspect is that your B+ will very likely change and sometimes well out of its tolorable limits. Changes in DCR and/or capacitance WILL change the final B+ output. This must be taken into consideration whenever making any changes in the power supply. The best thing to do, if you don't have a schematic with voltage listed, it to take measurements before making any changes so you know where you need to be when your done. Don't forget the power supply wiring.
Tube sockets - use Teglon whenever possible. Again, my opinion. Parts Connexion has some economy Teflon units that are very good.
Well, I guess that's enough for now. Play it smart and you can have a very good upgrade for a reasonable outlay of cash and when your done, you have the pride of doing it yourself.
Good info there, Thanks Bill!
OK then. Installed solid silver hook up wire in phono section. So far no complaints. Not thin or bright.
The new solder joints and wire now have some playing time to evaluate. Removing that selector switch has brought more to the table then expected. The improvement in clarity and detail is quite impressive. I thought it might be an improvement of some sort. Just did not expect such obvious results.
Next up are Deulund Cast .1 coupling caps [ two pairs ]. Then get rid of the Cornell Dubier caps with Solen as per the original design.
The Genrad power supplies need some loving care from John Weisner. So before any money is spent on caps the power supplies need some love as they are very old.
charles
Volume controls have arrived :thumb:
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We have lift off.
charles
Quote from: topround on December 18, 2012, 03:02:49 PM
(http://)
(http://)
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I was looking at this preamp not long ago on Agon or USAudiomart
I believe. Thought is was a good deal. Almost beat you to it.
Congrats.
This was sold from a private sale it was never listed so i did not beat anyone to it.
It is silly good for the money, even bone stock.
Just wait till i get my hands on it and mod it ..
and ruin it :duh
Good luck, Mike. I had that preamp and it was modded when I bought it. It tended to burn through tubes a bit quick, though.. I think whoever modded it might have done something to make the voltage too high on the tubes. So, maybe that B+ think Bill was talking about is worth understanding. I don't know, I don't mod preamps.
AllenZachary who frequents this board uses this preamp also.. and his was why I bought one. It is a good destination in hifi equipment. I could see someone being satisfied and stopping with this pre.
Unfortunately for me, there is no remote and 2 (that's two!) volume knobs... So much work! I had to sell it. ;)
-C
QuoteVolume controls have arrived
Ii think you will really like that volume control. For the money and with the Dale RN resistors, it's worth every penny. I have used them in the past and never had any problems with them except for those who wanted remote :?
Quote from: Carlman on January 05, 2013, 07:22:16 PM
It tended to burn through tubes a bit quick, though. I think whoever modded it might have done something to make the voltage too high on the tubes. So, maybe that B+ think Bill was talking about is worth understanding. I don't know, I don't mod preamps.
We are running an AI pre in my son's Mini-mancave system and one of the things I noticed was that even when you shut down the unit with the front panel power switch the tubes remain hot. Seemed like an awful waste of tube hours , especially if you only use the system a couple of times a week. I suspect this may be why it has been known to eat tubes. I plug the unit into a power strip the has a switch on and use that switch to cut off power from the unit and thereby shut down the tubes when it is not in use. We have been running the unit on a set of tubes I pulled out of one of my ARC units after a year and it has been going for over 18 months now with no problem.
I realize that the results with one unit and one set of tubes certainly doesn't prove anything on a general basis, but if you pull the plug to power down the tubes when the pre is not in use you may very well significantly extend the tube life on an AI pre. All I can say is it works for me. YMMV
Thanks Tom, very useful info. :thumb:
I noticed that the unit is sort of always on, with the orange light that turns green, I had no idea the tubes were still warm.
Kind of a dopey design.
I have used a RM 200 amp that had cap forming switches that kept the power running thru the caps at very low voltage, so they were always ready for play, but the tubes were cold.
Seems a much smarter design for tube gear.
Mike that AI pre has to be the biggest steal I ever made in this hobby. found it on the shelf at the Crack House with a price tag of $112 hanging from it. My son and I were planning to put together a second system for him to experiment with and I couldn't get my wallet out fast enough when I saw this. I figured at that price even if I had to put some repairs into it it would be a great deal. Well I took it home powered it up and it has played perfectly from day one.
See, the Crack House isn't just good for records...... 8)
Tom,
I have a AudioNote kit preamp here as well, it is the L2 with phono, another very nice design and pretty reasonable.
This is another design that I think alot of people would like.
The AI is a bit better than the AN and build quality is a bit higher on the AI than the AudioNote. But the AudiuoNote is a kit and the chassis are crap and cheap
I paid $400 for the AI,and that is the going rate, the phono section is not that good on the AI, the phono in the AN is much better, but the linestage in the AI is better than the AN.
I use a separate phono anyway, so what is built in is not really necessary for me. But fro $400 the Linestage of the AI is quite good. Not world class mind you but very good for no money in this hobby.
I will put the volume controls in this weekend and see what happens.
Mike
Mike, here are 3 PS caps in stock at Mouser. It's a long link so I will put it in this link:
LINK (http://www.mouser.com/Passive-Components/Capacitors/Aluminum-Electrolytic-Capacitors/Aluminum-Electrolytic-Capacitors-Leaded/_/N-75hqwZscv7?P=1z0wrkmZ1z0z819Z1z0x6pw&FS=True)
The Vishays are 26 x 67mm axial leads, bipolar $16.53 each :shock:
The Nichicons are 22x40mm axial bipolar $7.04 each 8)
Based on smaller physical size that you need and lower price I think the Nichicons are the wtg. They're not in stock at Digikey.
Here is a photo of the volume knob connected to the volume pot
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Here is a photo of the volume pot inside the chassis
(http://)
and here
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as you can see, they don't fit, so i am off to find some new electrlytic caps that are smaller, to replace the big blue mallory caps from the past.
New caps are smaller and better, and will give me wiggle room to fit the volume pots.
So the story takes a break until the caps arrive
This might help with your hookups Mike:
http://www.beavishifi.com/articles/Volume_Control/ (http://www.beavishifi.com/articles/Volume_Control/)
Quote from: richidoo on January 17, 2013, 09:33:17 PM
This might help with your hookups Mike:
http://www.beavishifi.com/articles/Volume_Control/ (http://www.beavishifi.com/articles/Volume_Control/)
Excellent read and info. The professor strikes gain.
charles
Here is a shot of the Khozmos in my CAT...was worth all of its 200.$
(http://images2.snapfish.com/232323232%7Ffp5438%3A%3Enu%3D4568%3E549%3E534%3EWSNRCG%3D35%3C%3A47567%3B348nu0mrj)
Looks good :thumb:
I wanted to try those but they were too expensive for this project, especially since I will probably sell the Audible after the project.
Doesn't CAT use a ladder attenuator?
Quote
Doesn't CAT use a ladder attenuator
Yeap, 23 step. I wanted 'finer' steps since I listen mostly late at night and this CAT is 1990 vintage. My next updating would be the electrolytic caps...
Here is a pic of the old vol/balance..
(http://images2.snapfish.com/232323232%7Ffp543%3A6%3Enu%3D4568%3E549%3E534%3EWSNRCG%3D35%3C%3A47567%3A348nu0mrj)
I think the original CAT's were notorious for having rather large steps, so you were either too loud or too soft and usually never quite right.
I think there is an easy way to solve for that though (engineers, please correct me if I am wrong) by installing a switch with a second grounding resistor with a value that would allow a half step.
Quote from: AcidJazz on February 04, 2013, 01:56:04 PM
Here is a shot of the Khozmos in my CAT...was worth all of its 200.$
(http://images2.snapfish.com/232323232%7Ffp5438%3A%3Enu%3D4568%3E549%3E534%3EWSNRCG%3D35%3C%3A47567%3B348nu0mrj)
As a former CAT owner. Curious as to the difference had from the Khozmos. I'm considering them for the Loesch & Weisner preamp. What did you gain ?
charles
Aside from smaller steps of volume...a seemingly deeper more expansive soundstage, a 'softening' of a hardness I thought was there at higher volumes (I sorta convinced myself I was hearing the hardness of the metal film resistors lol).
THe expanded soundstage thing might just be having the right and left channel pots separate. Then there is the elimination of the balance control straddling the right and left channel together.
Rollo, your old CAT says Hi... :thumb:
Cool thanks. The CAT was a dear friend. Glad to hear it has a new good home. They are special in the preamp arena. Revealing as all heck. ENJOY !!!
charles