BigGuyAtTheBack Posted January 6, 2015 Share Posted January 6, 2015 Hi folks, I'm just about to build the Kreuzer preamp and just wondered if anyone on the forum had done so and what they though of it. I have a BBE BMax preamp and I just can't get on with that passive tone stack! So I thought I'd have a crack at this Kreuzer preamp. Looking at the schematic it looks pretty good. Any thoughts? Cheers Cammie Quote Link to comment Share on other sites More sharing options...
nick Posted January 6, 2015 Share Posted January 6, 2015 I've built clone of the Zeibek Submarine which is based on Albert Kruezer's preamp - more stripped down version, very easy build. I like it, it's great little preamp. I use it a lot. Quote Link to comment Share on other sites More sharing options...
Passinwind Posted January 6, 2015 Share Posted January 6, 2015 (edited) [quote name='BigGuyAtTheBack' timestamp='1420554590' post='2650557'] Hi folks, I'm just about to build the Kreuzer preamp and just wondered if anyone on the forum had done so and what they though of it. I have a BBE BMax preamp and I just can't get on with that passive tone stack! So I thought I'd have a crack at this Kreuzer preamp. Looking at the schematic it looks pretty good. Any thoughts? [/quote] Which one? He did a few different designs. Edited January 6, 2015 by Passinwind Quote Link to comment Share on other sites More sharing options...
BigGuyAtTheBack Posted January 6, 2015 Author Share Posted January 6, 2015 I'll have to look into that one thanks Nick. Passinwind its the Jfet Bass Preamp Ver 2.1 07082002 3 get design with the switchable eq. Quote Link to comment Share on other sites More sharing options...
Passinwind Posted January 6, 2015 Share Posted January 6, 2015 [quote name='BigGuyAtTheBack' timestamp='1420571731' post='2650813'] I'll have to look into that one thanks Nick. Passinwind its the Jfet Bass Preamp Ver 2.1 07082002 3 get design with the switchable eq. [/quote] Cool, I'll be interested to see how it goes for you. Personally, I'd at least swap out the first opamp for something a little more modern. My default choice for BiFETs is usually the OPA2132 or OPA2134, although I've been messing with quite a few others recently too. Quote Link to comment Share on other sites More sharing options...
BigGuyAtTheBack Posted January 7, 2015 Author Share Posted January 7, 2015 Thanks for the suggestions Charlie. I'll socket the IC's and try the 072's and the OPA2134's just to see if I can hear a difference. I've read a few of your posts on Talkbass, always informative! Quote Link to comment Share on other sites More sharing options...
Passinwind Posted January 7, 2015 Share Posted January 7, 2015 [quote name='BigGuyAtTheBack' timestamp='1420624390' post='2651346'] Thanks for the suggestions Charlie. I'll socket the IC's and try the 072's and the OPA2134's just to see if I can hear a difference. I've read a few of your posts on Talkbass, always informative! [/quote] Are you going to use Mr Kreutzer's printed circuit board layout? I had intended to try building that circuit up myself sooner or later, but my plate's a little too full already right now. Quote Link to comment Share on other sites More sharing options...
BigGuyAtTheBack Posted January 17, 2015 Author Share Posted January 17, 2015 Hi Charlie, I'm going to Veroboard it as I don't have the facillities to make PCB's. The last time I made PCB's was back in the early 80's when I was an electronics tech. The 741 was king! Just started building it now but the mancave is a bit cold as the wife has nicked my gas heater, slow progress! Quote Link to comment Share on other sites More sharing options...
Passinwind Posted January 17, 2015 Share Posted January 17, 2015 (edited) [quote name='BigGuyAtTheBack' timestamp='1421489084' post='2661783'] Hi Charlie, I'm going to Veroboard it as I don't have the facillities to make PCB's. The last time I made PCB's was back in the early 80's when I was an electronics tech. The 741 was king! Just started building it now but the mancave is a bit cold as the wife has nicked my gas heater, slow progress! [/quote] Ah, 741s...can't say I miss 'em much. Getting circuit boards done in small quantities is trivially easy these days, but the learning curve on doing your own board layouts can be a bit steep IME. I'm just finishing up my latest preamp build. I'll post some pics and fluff once I get it all together. It's quite similar to the one Chienmortbb is using in the Amp Build Diary thread and there are pics of my boards in that thread. Edited January 17, 2015 by Passinwind Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted January 17, 2015 Share Posted January 17, 2015 [quote name='Passinwind' timestamp='1421513771' post='2662157'] Ah, 741s...can't say I miss 'em much. Getting circuit boards done in small quantities is trivially easy these days, [b]but the learning curve on doing your own board layouts can be a bit steep IME.[/b] [/quote] what's the hard bit? what makes it steep? Quote Link to comment Share on other sites More sharing options...
Passinwind Posted January 18, 2015 Share Posted January 18, 2015 [quote name='LukeFRC' timestamp='1421537771' post='2662590'] what's the hard bit? what makes it steep?[/quote] Many of the freeware layout programs have pretty arcane and/or limited component library formats, so I find that I spend a lot of time building my own component footprints. Things like ground plane layouts often still feel like black art to me too. And even for someone like me who has always been pretty used to winging things and "fixing it in the mix" later (rework and mods), I've found little mistakes on almost every original revision board I've done so far. I do find putting in the effort very worthwhile though. Quote Link to comment Share on other sites More sharing options...
UglyDog Posted February 24, 2015 Share Posted February 24, 2015 Looks like an interesting project. I priced the components up and without PCBs or case it all works out at roughly 26 quid. At that sort of price it's almost worth a try for the hell of it. Anybody built one or seen/used one? [url="http://www.albertkreuzer.com/preamp.htm"]http://www.albertkreuzer.com/preamp.htm[/url] Quote Link to comment Share on other sites More sharing options...
Passinwind Posted February 24, 2015 Share Posted February 24, 2015 I've not built one, but it looks pretty worthwhile and people I trust have told me it sounds good. Someone else posted about this last month: http://basschat.co.uk/topic/252766-kreuzer-bass-preamp/ Please keep us posted on how it goes. I always enjoy seeing how other people manage their DIY builds, and I'm just finishing up a [url="http://www.talkbass.com/threads/a-diy-1-2-rack-bass-preamp.1135423/"]new one of my own design[/url] at the moment, FWIW. Quote Link to comment Share on other sites More sharing options...
UglyDog Posted February 24, 2015 Share Posted February 24, 2015 [quote name='Passinwind' timestamp='1424793350' post='2700536'] I've not built one, but it looks pretty worthwhile and people I trust have told me it sounds good. Someone else posted about this last month: [url="http://basschat.co.uk/topic/252766-kreuzer-bass-preamp/"]http://basschat.co.u...er-bass-preamp/[/url][/quote] Oh bum, I missed that Feel a bit of a twit for starting this thread now! That ½ rack pre of yours is gorgeous. Quote Link to comment Share on other sites More sharing options...
Passinwind Posted February 24, 2015 Share Posted February 24, 2015 (edited) [quote name='UglyDog' timestamp='1424794760' post='2700544'] Oh bum, I missed that Feel a bit of a twit for starting this thread now! That ½ rack pre of yours is gorgeous. [/quote] Thank you! Mr. Kreuzer passed away a few years ago, so I wonder if anyone is doing anything with the board layout he published, or has done an updated one? I'll look into that a bit. Edited February 24, 2015 by Passinwind Quote Link to comment Share on other sites More sharing options...
jensenmann Posted February 28, 2015 Share Posted February 28, 2015 I just stumbled across this DIY project which has similarities with what I built a few month ago. It´s basically a Bassman 135 converted to FET transistors. My version had the original tonestack - EQ with switchable frequencies for every filterband. The sonic quality of my build reminded me on my Bassman. Success! That´s what I was looking for. The EQ behaved similar, only the fequency switching mod didn´t turn out as exiting as I expected. It seems that Mr Kreuzer was on the right track with buffering the EQ, though he used a different topology. I think I´ll go the same route. My DIY background is studio gear, that´s where I´m coming from. I´d say +1 to passinwind´s comments about TL072s and OPA2134s from that point of view. But in my expierience with MI gear I´d propose to use TL072s because their artefacts make a certain sound which might help a signal to cut through on stage. HiFi sounds are not the easiest to handle thing for me on stage. Quote Link to comment Share on other sites More sharing options...
Passinwind Posted February 28, 2015 Share Posted February 28, 2015 [quote name='jensenmann' timestamp='1425153375' post='2704614'] . I´d say +1 to passinwind´s comments about TL072s and OPA2134s from that point of view. But in my experience with MI gear I´d propose to use TL072s because their artefacts make a certain sound which might help a signal to cut through on stage. HiFi sounds are not the easiest to handle thing for me on stage. [/quote] The Fender tone stack can get a bit lost due to all that inherent mid-scoop, for sure. I built up Rod Elliot's Project 27, which is a lot like how you've described yours. You might give the LT1169 a try if OPA 2134/2132 is too "gooey" for your taste, but you still want lower noise than the TL072 affords. I used Rod's bright switch circuit in mine, which cuts like crazy if desired. The Keutzer preamp's tone stack is a pretty standard Baxandall variant, which can be pretty hi-fi, but can also boost mids pretty effectively. In my own designs I sometimes like to mix the two, with active bass and mids in one section and a lossy passive treble control in another, later stage. All of this stuff depends a lot on playing context. I don't play fretted bass, ever, and rarely play much rock these days either. DIY builds can be great for really nailing things down for your own wants and needs, if you don't go crazy first! Quote Link to comment Share on other sites More sharing options...
jensenmann Posted March 1, 2015 Share Posted March 1, 2015 After a second look at the Kreutzer pre I´d strongly vote for a chip with better output drive capability than a TL072. The first amp sees a load <2k which is the minimum rated load for a TL072. It will distort depending on the setting of the pots. Besides that I´d lower R12+R13 to reduce thermal noise and then use a BJT input chip for better noise performance. Inside an EQ circuit it will make a difference. Thanks for the LT1169 info. I´ll give it a try. Some parameters do look promising. Quote Link to comment Share on other sites More sharing options...
Passinwind Posted March 1, 2015 Share Posted March 1, 2015 [quote name='jensenmann' timestamp='1425212546' post='2705058'] Thanks for the LT1169 info. I´ll give it a try. Some parameters do look promising. [/quote] It's a pretty nice sounding DIP-8 chip, LT1113 is decent too. Not the fastest or latest-greatest, but sometimes that can be a good thing. Quote Link to comment Share on other sites More sharing options...
alambike Posted December 20, 2015 Share Posted December 20, 2015 Does anyone know what are the BF245 JFETs ? Because I found three types of those: BF245A, BF245B and BF245C. Thank you Quote Link to comment Share on other sites More sharing options...
jensenmann Posted December 20, 2015 Share Posted December 20, 2015 If there is no reference to A, B or C then it doesn´t matter which one you are using. Quote Link to comment Share on other sites More sharing options...
billyboyUnicorn guitars Posted October 7, 2023 Share Posted October 7, 2023 I built the Kreutzer preamp in its original form, and found it was less noisy than at first expected. I reckon all the rest of your gear makes enough noise to mask any noise made by a TL072, but change it if you must... The LT1169 is a good coice. I have also built a cut n' shut version of the preamp and put it in a 100W 'Lead' guitar amp: I am quite impressed with results but would make the observation that a bit more gain would be useful providing the first amplifier isn't swamped. BillyboyUnicorn guitars 1 Quote Link to comment Share on other sites More sharing options...
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