Transformer ideas for Ian Thompson bell mic pre

[Thegoldenlockedlamb]

Hello everyone !

I am in the process of having Ian Thompson bell build a 12 channel line mixer and I am going to build his preamps And eqs to accompany it. I plan on building the preamps with zero negative feedback fixed gain with different pads and in his SRPP topology . I am trying to get a nice colored sound out of it and thought I would ask the forum what transformers they would recommend for a vintage colored sound . I am a big fan of
Mid 60s to about 1973 La sound like the mamas and papas, Jefferson airplane ,the beach boys pet sounds album, Crosby , stills , nash , buffalo Springfield ,the carpenters, Todd rundgren , carol king , America ( I’m actually not sure where America recorded but I love their sound ) . All of these seem to be kind of soft /dark in the topend which I find pleasing .obviously there is more at play than just transformers but I would love to hear your opinions ! I have spoke to David geren at cinemag ( a really nice and helpful guy ) and he recommended the cm-75101 , have any of you used it ? And if so do you think it would fit the sound i’m after ? I also have been talking To Chris at oep and he mentioned they have a nice version of a 10468 Like a never style transformer and is open to building custom stuff too and letting me try samples as well .

Also I should mention Ian’s design calls for a 1:10 input transformer and 2.4K:600 ohm output transformer .

Look forward to hearing any all opinions and sorry to write a novel!

Thanks !

Ethan

 

[gyraf]

It's really hard to advice on how to achieve certain undefined subjective properties of transformer sound - and most of what we see on the topic is simply BS unfortunately.

I don't think there is any way around trying and experimenting for yourself, then deciding what you like. These things does simply not generalize into something generically objectively "better", contrary to the narrative and almost desperate desires from the hifi crowd (and parts of the uninformed audio crowd too). Listen to two aspects: How do it overload, and how do it treat very-small signals like natural room reverb tails.

For me, I really like the Lundahl LL5402 wired 2:1 as output transformer for a ECC82 or ECC88 SRPP stage - even though this setup is theoretically flawed. This used in e.g. the G-pultec and G9 projects (and some of my commercial products). For input, what you hear is what you get. I really like the signature of the Lundahl LL1530, ymmw as always

But in the end, I'm not at all sure that I'd enjoy having 12 channels of similar-sounding transformerniceness - there's a fine line where the nicelyness turns into toomuchlyness, and often you will only discover this after using it for some time, at which point it may be too late to recalibrate cognitively (don't ask me how I know)

/Jakob E.

 

[Dylan W]

If you’re after the 60s sound, you should try UTC iron, like the A10. It’s instant “that sound.”

The originals are expensive, but they definitely have the mojo.

TAB AMI makes a repro, as well as Crimson Transformers. I haven’t heard either of them. If you decide to try them and compare to the original UTC, you should report back to the forum and let us know how they are.

PS the UTC ouncers have even more of that sound and can also be used for mic input - they just overload more quickly so you have to have some kind of pad ready to go

 

[Ó Draighnáin]

I also like dealing with Dave at Cinemag.

I use a pair of cm-75101 transformers wired 1:5 on the output of my console's stereo bus (16 channel passive). I have them configured so that they can be switched in and out of the signal path (a bit clumsy, I used a pair of SP4T switches). The post bus gain is adjustable to compensate. I have been very happy with them (in an admittedly different application) and generally leave them "in". I think the 75101s have slightly lower headroom than some of the other Cinemag 1:10 input transformers (like the bigger one than has the primary tap for ribbon mics).

There are so many variables at play in a console that I could not categorically affirm that these transformers will help give you the sound you are after but I suspect they will not take you away from that sound. Amps (and their matching to the transformers) will play a huge part.

I have also spoken to Chris at OEP about output transformers and he sent me two samples (a 1:1 and a 1:2 neither of which are available to purchase at any retailer as far as I am aware) both of which were of high quality. I think that you are looking in good places but I do not know if this will lead you towards the sound you are after. In any event, your console is going to be superb by the sounds of it.

 

[Ike Zimbel]

I have some NOS vintage o/p transformers that are former SSI (Suburban Sound International) stock. They were definitely used as the o/p transformers on the SS-3, 8-channel rack mount mixer, see pics.
These are 1:5 and have about 7dB of gain in them. I will try and get the other specs measured in the next day or so.

 

[Thegoldenlockedlamb]

It's really hard to advice on how to achieve certain undefined subjective properties of transformer sound - and most of what we see on the topic is simply BS unfortunately.

I don't think there is any way around trying and experimenting for yourself, then deciding what you like. These things does simply not generalize into something generically objectively "better", contrary to the narrative and almost desperate desires from the hifi crowd (and parts of the uninformed audio crowd too). Listen to two aspects: How do it overload, and how do it treat very-small signals like natural room reverb tails.

For me, I really like the Lundahl LL5402 wired 2:1 as output transformer for a ECC82 or ECC88 SRPP stage - even though this setup is theoretically flawed. This used in e.g. the G-pultec and G9 projects (and some of my commercial products). For input, what you hear is what you get. I really like the signature of the Lundahl LL1530, ymmw as always

But in the end, I'm not at all sure that I'd enjoy having 12 channels of similar-sounding transformerniceness - there's a fine line where the nicelyness turns into toomuchlyness, and often you will only discover this after using it for some time, at which point it may be too late to recalibrate cognitively (don't ask me how I know)

/Jakob E.

Hey Jakob,
Thank you for replying ,I always enjoy your posts on here and got try one of your eqs a few years ago and thought it sounded great .

Yes sound is very subjective and hard to pin down sometimes . I will say I have used a few different utc transformers , mainly the original used in the La2a I had a couple he built of and compared to others with new transformers in blind listening test the one with utc’s were a little smoother and colored the sound more , but this is just one instance and maybe could be recreated with other variables ?

Very interesting , excuse my ignorance but what does the 2:1 do differently than the 4:1 sound wise ?


You are probably right about this, but I’m probably on a weird minority where everything I record has sort of a vintage vibe to it where this color is useful and all the people wanting to record with me are after this same sound . I’m not a big outfit and I’m Not into anything sounding at all , and not really looking to make it big or anything so I guess I’m my kind of weird case it might work out okay haha. Thank you for your help My friend .

Best,

Ethan

 

[gyraf]

aah, if you're sure of your taste, that's something entirely different - and not in risk of suffocating in too-much'yness.

2K4:600 is 2:1 (impedance ratio is turns ratio squared) - is this why you ask about 2:1 / 4:1?

/Jakob E.

 

[jensenmann]

If you´re looking for 1960-70s sound then get a tape deck to record on. That makes more of a difference than the console.

 

[Thegoldenlockedlamb]

If you’re after the 60s sound, you should try UTC iron, like the A10. It’s instant “that sound.”

The originals are expensive, but they definitely have the mojo.

TAB AMI makes a repro, as well as Crimson Transformers. I haven’t heard either of them. If you decide to try them and compare to the original UTC, you should report back to the forum and let us know how they are.

PS the UTC ouncers have even more of that sound and can also be used for mic input - they just overload more quickly so you have to have some kind of pad ready to go

Hey Dylan,

Thanks for the reply . I think you are right and matches up to what I said in my post above . I still have an old A26 left that is supposedly what was used as then input transformer to the Fairchild 660 , I think I got it for like $50 by accident a few years ago when I was trying to get the iron to build the la2a haha.

Yes I’ve noticed the tab and crimson versions of an A10 . I sent crimson a message also yesterday .

The 0-1 ouncer was my first thought actually ! I sent an mail to oep last night asking if I sent them one to dissect if they could build one, though I hate to destroy a vintage transformer , but maybe it would help others And myself get these old things reproduced somewhat .

I wonder if there is a file on here in the technical documents that could be used for specs and materials ? I’m kind of New here still so I sometimes have a hard time finding these things ( I think it’s the operator (me!) this case and not the machine though! Haha)


Of course if I end up using your me of those A10 or some other utc style custom clone I will definitely report back!

I very much appreciate this community and all the help and ideas it has given me over the years . I’m nowhere near the technical level of most of you guys but I’m slowly learning ! Thank you !

 

[Thegoldenlockedlamb]

I also like dealing with Dave at Cinemag.

I use a pair of cm-75101 transformers wired 1:5 on the output of my console's stereo bus (16 channel passive). I have them configured so that they can be switched in and out of the signal path (a bit clumsy, I used a pair of SP4T switches). The post bus gain is adjustable to compensate. I have been very happy with them (in an admittedly different application) and generally leave them "in". I think the 75101s have slightly lower headroom than some of the other Cinemag 1:10 input transformers (like the bigger one than has the primary tap for ribbon mics).

There are so many variables at play in a console that I could not categorically affirm that these transformers will help give you the sound you are after but I suspect they will not take you away from that sound. Amps (and their matching to the transformers) will play a huge part.

I have also spoken to Chris at OEP about output transformers and he sent me two samples (a 1:1 and a 1:2 neither of which are available to purchase at any retailer as far as I am aware) both of which were of high quality. I think that you are looking in good places but I do not know if this will lead you towards the sound you are after. In any event, your console is going to be superb by the sounds of i

I also like dealing with Dave at Cinemag.

I use a pair of cm-75101 transformers wired 1:5 on the output of my console's stereo bus (16 channel passive). I have them configured so that they can be switched in and out of the signal path (a bit clumsy, I used a pair of SP4T switches). The post bus gain is adjustable to compensate. I have been very happy with them (in an admittedly different application) and generally leave them "in". I think the 75101s have slightly lower headroom than some of the other Cinemag 1:10 input transformers (like the bigger one than has the primary tap for ribbon mics).

There are so many variables at play in a console that I could not categorically affirm that these transformers will help give you the sound you are after but I suspect they will not take you away from that sound. Amps (and their matching to the transformers) will play a huge part.

I have also spoken to Chris at OEP about output transformers and he sent me two samples (a 1:1 and a 1:2 neither of which are available to purchase at any retailer as far as I am aware) both of which were of high quality. I think that you are looking in good places but I do not know if this will lead you towards the sound you are after. In any event, your console is going to be superb by the sounds of it.

Hey my friend ,

Thank you for the reply . Oh yes Dave is great! He’s answered a lot of questions and been very helpful when it really hasn’t made him any money so far , so I would love to buy some stuff from him .

That’s good to hear the cm-75101 at least won’t keep me from getting to the sound I’m after and the lower headroom I imagine would be a plus .

You are right there are a lot of variable going on in boards and all other gear in the chain , even On the old records I’m sure al other bounces through tape and tape machine electronics , the mics , compressors , and room all influence the sound ( plus’s the source musician and instruments etc ) so I may be overthinking this a bit , but I try to get as close as I can to the sound in my head .

That’s great to hear about oep ! Chris told me a similar thing , that they have a lot more stuff available it’s just not on the more “ off the shelf product “ vendors .

Another company I have heard good things about is electromag( correct me if I’m wrong on the name of this one ) in the UK . I think Ian and Holger have used them for custom work . Have any of you dealt with them or have an email or contact info on them? I tried googling but didn’t have much luck .

I think you are right , we are really lucky with all the options for transformers these days . I think you are right, Ian is a great guy and has been a huge help to me . His work is also great .

Thanks again!

 

[Thegoldenlockedlamb]

I have some NOS vintage o/p transformers that are former SSI (Suburban Sound International) stock. They were definitely used as the o/p transformers on the SS-3, 8-channel rack mount mixer, see pics.
These are 1:5 and have about 7dB of gain in them. I will try and get the other specs measured in the next day or so.

Hey Ike,

Thanks for the reply , it’s funny I saw one of those mixers a year or so ago and thought it looked cool! Man I very much appreciate your help!

 

[Ike Zimbel]

I've had a few clients who have relied on those mixers, they all love them!

 

[Thegoldenlockedlamb]

aah, if you're sure of your taste, that's something entirely different - and not in risk of suffocating in too-much'yness.

2K4:600 is 2:1 (impedance ratio is turns ratio squared) - is this why you ask about 2:1 / 4:1?

/Jakob E.

Hey Jacon, thanks again for your reply . I hope my last reply didn’t come off snarky ( that wasn’t my intent at all haha) , I appreciate you trying to help me , as you are right sometimes too much color can choke things off a bit . I guess my reasoning for going for a more colored product is most things I’ve tried haven’t gotten me all the way there , it’s like they get about half way but are afraid to design it too vintage , which Makes sense as I know most people do mostly modern or a mix of vintage and modern in their studio so they Have to apeal to a bigger market for obvious financial reasons .

Ah yes sorry that was my mistake on that, I thought 2.4K:600 was 4:1 all this time! As up I can see I’m still kind of green on a lot of this, thank you for explaining this to me . I very much appreciate it .

 

[Thegoldenlockedlamb]

If you´re looking for 660-70s sound then get a tape deck to record on. That makes more of a difference than the console.

Hey Jensenmann,

Thanks for your reply. You aren’t wrong about tape and especially certain formulas of it . About 8 years ago I had a studio made up of a 1979 mci jh536C , Sony apr24 2” machine , and an ampex 440b 2 track. I could get pretty good mid mid to late 70s sounds , the mci was somewhat colored and the 440 was more colored as well , but the Sony was really transparent . I have a feeling if I had used a more colored console or more colored tracking deck with lower headroom tape formula I could have gotten closer to the late 60s early 70s thing. I was going for. It did sound great non the less though ! I unfortunately had to sell all of it after I lost a good paying job and went back to work for my family’s business that doesn’t pay that great with two young kids haha . But money is a little better so I have been trying to rebuild the studio again . I am using an old otari( iz) radar 2 with their classic converters and though it is digital , they somehow made it have a topend and midrange they sound very tape like in my opinion , not as nice on the low end as a 2” 16 track or 1” 8 track running at 15 ips. But I thought if I used the tube console , the radar for tracking since it’s highs and mids are similar to tape and then maybe get a 2 track recorder ( more than likely an ampex 440 again but open of suggestions !) that I would get close to the sound I’m after. I’ve even thought of building some like level devices to go in front of the radar to mimic the electronics of a tape machine . I have tried to avoid getting a multi track tape machine as they are expensive right now still and can be hard to maintain as some use proprietary electronics and parts ( Sony was bad about this ). Though I have considered a scully or ampex 1” 8 track if I run across a deal since they are fairly simple and easy to work on compared to more complicated machines .

Sorry to write a book by the way! And thank you again for your response .

 

[Thegoldenlockedlamb]

I've had a few clients who have relied on those mixers, they all love them!

That’s really cool! Are you using them as summing mixers or do they have preamps also? I assume the former , very cool! How would you describe the sound of them? ( I know this is subjective but always interesting to me non the less!) . Does your studio have a website I could check out ? I always enjoy checking out peoples studios and feting ideas etc , I might like gear a bit too much haha . Thank you again my friend .

 

[Ike Zimbel]

I just service them...I've been into about 6 or 8 of them as my late friend and mentor, Neil Muncy, was the guy that designed them. He ended up with a few of them and I serviced those, in some cases adding direct outputs. Yes, they have pre-amps, featuring a custom Beyer "peanut" transformer. I haven't been in touch with any of the owners for several years so I need to see if they're still around before I say "hey, listen to this!" I checked one of their web sites just now, and there was some great music on it, but it hasn't been updated since 2013. I'm pretty sure the most recent album on that site was done entirely on the pair of SS-3's that he had at the time, but I'd like to confirm.

 

[My3gger]

"Not in risk of suffocating in too-much'yness" is good advice by Jakob. If you go for Cinemag try CM David suggested, CMMI is nice too without adding much sound. Tab Funkenwerk UTC like model is also worth a try if importing isn't expensive like as it is to Europe.

 

[Thegoldenlockedlamb]

"Not in risk of suffocating in too-much'yness" is good advice by Jakob. If you go for Cinemag try CM David suggested, CMMI is nice too without adding much sound. Tab Funkenwerk UTC like model is also worth a try if importing isn't expensive like as it is to Europe.

Hey my3gger,

Yes I think if the utc style stuff doesn’t pan out I will go with the cm75101.

Are tab funkenwerk in the U.S. ? I’ve always heard of them and Oliver but I never was sure as dumb as that sounds .

Thanks!

 

[Thegoldenlockedlamb]

I just service them...I've been into about 6 or 8 of them as my late friend and mentor, Neil Muncy, was the guy that designed them. He ended up with a few of them and I serviced those, in some cases adding direct outputs. Yes, they have pre-amps, featuring a custom Beyer "peanut" transformer. I haven't been in touch with any of the owners for several years so I need to see if they're still around before I say "hey, listen to this!" I checked one of their web sites just now, and there was some great music on it, but it hasn't been updated since 2013. I'm pretty sure the most recent album on that site was done entirely on the pair of SS-3's that he had at the time, but I'd like to confirm.

Oh wow that’s really cool that you knew the designer . That’s neat you added direct outs on some . I’ve always been curious about those beyer peanut transformers , how do you like the sound of those ?

I very much appreciate that ! Don’t work too hard trying to check on my account
Though. I very much appreciate your help so far .

 

[Thegoldenlockedlamb]

I also thought i would mention to you guys I like Ed Anderson’s versjon of the 2622 he makes for capi , to me it seems fairly colored and sort of reminds me a bit of the utc I had in try La2a build . I used them in pier Paola’s ma-1 preamp builds . I would love to have Ed build some kind of utc Style input or maybe if that’s not possible some kind of 1:10 version of his 2622 . I don’t know if Ed would be interested in small quantities though . Have any of you had him build you anything ?