That would work beautifully! But it doesn’t need to be autoformer… Easiest would be 1:2 transformer, and if you ever wanted to wire it as balanced XLR in the future, that would be very easy.
Lots of choice. Also, adding a transformer does something magical to the sound. Hard to describe, but it’s absolutely there. I love it, very beautiful.
Lots of choice. Also, adding a transformer does something magical to the sound. Hard to describe, but it’s absolutely there. I love it, very beautiful.
thanks for reminding me of this autoformer, subs ZM thread long time ago but still never purchased any maybe due to the cost hahaha. another 30% for customs fee will end around 650 eur which is alot for me
anyway i find this local made LoT which will cost me around 140usd per pair, stated it can be configured from 1:2 up to 1:5
any input which gain should I choose? will 1:5 become too much gain or just keep 1:2?
anyway i find this local made LoT which will cost me around 140usd per pair, stated it can be configured from 1:2 up to 1:5
any input which gain should I choose? will 1:5 become too much gain or just keep 1:2?
The impedance reflected back to the buffer by the load will be the load impedance divided the square of the turns ratio. So if your load is 10k ohms and you use the 1:5 ratio, the load on the B1 will be 400 ohms. At 1:2 it will be 2500 ohms. The output Z of a B1 buffer is about 150 ohms if memory serves, but the standard schematic shows a 1k resistor between the output cap and the output. ZM once suggested removing or jumpering that output resistor when presenting the B1 with a heavier than normal load like from an line transformer.
more info about inductances of thingie?
from numbers and winding arrangement, configurable ( in pure transformer mode) as 10K: 300 (which is 5.77:1 voltage vise) and 10K:1200 (which is 2.88:1 voltage wise)
late in my head, so I can't fathom proper ratios for autoformer config now
from numbers and winding arrangement, configurable ( in pure transformer mode) as 10K: 300 (which is 5.77:1 voltage vise) and 10K:1200 (which is 2.88:1 voltage wise)
late in my head, so I can't fathom proper ratios for autoformer config now
ZM, ranshdow
i'm totally noob about this transformer configuration, but i can show the seller notes about his product on attached picture. please enlight me on what i should mention to the seller
to make it easier, i make configuration of B1 - LIT - B1
i'm totally noob about this transformer configuration, but i can show the seller notes about his product on attached picture. please enlight me on what i should mention to the seller
to make it easier, i make configuration of B1 - LIT - B1
ok no info about inductance
anyhow - confirm what exactly you bought, so we can go slightly deeper in options and - clarify what you mean by "B1-LIT-B1"?
so, to be sure - you bought exactly xformers shown on picture in post #522?
why using B1- xformer - B1?
talk more about rest of amplification, so we can deduce what's best scenario ............ it's hardly that you need B1 after xformer
why using B1- xformer - B1?
talk more about rest of amplification, so we can deduce what's best scenario ............ it's hardly that you need B1 after xformer
I'm thinking about SIT L'Amp, because it has no input buffer. for FW clone should be no issue due to B1 built in amplifier
Seems to me if you want a really good B1 type pre with gain then just get the Iron Pre. It does everything and does it very well. I have one.
But I also wanted more gain in my home brew B1 Rev 2 so just added a top quality op-amp (LM4562) gain stage in front of the buffer stage. It works and sounds great plus allows fine control of the gain amount and input Z and there are no reactance concerns. .... and its costs much less than transformers. That's just my 2 cents. You have options available and they are all good.
But I also wanted more gain in my home brew B1 Rev 2 so just added a top quality op-amp (LM4562) gain stage in front of the buffer stage. It works and sounds great plus allows fine control of the gain amount and input Z and there are no reactance concerns. .... and its costs much less than transformers. That's just my 2 cents. You have options available and they are all good.
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it's really useful if you respond to questions ....... I'm still not sure that you bought exact xformers shown in post #522, and list shown in post #525 is general one .....
when you confirm xformers you're having in your hands, I can go in simple calc exercise, to see what you have with (my preferred) autoformer arrangement
ZM
#522 : picture of the product
#525 : description of the product
no i haven't bought it yet.
what i experience now, with M2 i should turn 25k potentio in 13.00-14.00 position, for SIT should be full open. while for J2 in 10.00-11.00 position
#522 : picture of the product
#525 : description of the product
no i haven't bought it yet.
what i experience now, with M2 i should turn 25k potentio in 13.00-14.00 position, for SIT should be full open. while for J2 in 10.00-11.00 position
ok, to paraphrase my self - above written what you get with regular xformer arrangement
if you connect it as autoformer, you'll get 6.77V/V or 3.88V/V gain
say that B1 is having Rout in range of 40R, so here is what you have with B1 followed with autoformer (without second B1 in cascade, after autoformer)
in first case Rout should be 6.77^2*40R
in second case 3.88^2*40R
that, if you buy xformer shown on pic in #522
Hello. I started searching simple cheap hi-quality buffer design, and found B1 but hesitated to spend not a small budget for condensers. Then reached here, being excited by the most simple beautiful circuit. Later I also found DCB1, and am wondering which to build. If there is anybody tried both already and can provide any comment about the difference, it would be appreciated. I don't want to call "comparison" as I respect all circuit designers (I can't do more than connecting existing schematics), both appear very nice design and there are many DIYer who enjoy them. To me, B1 Rev.2 appears more "symmetric". That's really attractive. DCB1's lower K170 works only as CCS not amplification, am I wrong? However that pureness of DCB1 relying on single K170 looks more reliable. My fear in B1 Rev.2 is, the two JFET, K170 and J74 can hardly be really symmetric. We can match IDSS easily, even matching Vgs also possible when there are enough stock, but there can remaining difference I'm afraid. I know my ears won't hear the asymmetricity of them, and I'm sure I would be happy when I could build any of these two, though...
Single supply PSU Vs. bipolar supply PSU.
Coupling caps vs. complimentary transistors.
Your choice, both sound wonderful.
Coupling caps vs. complimentary transistors.
Your choice, both sound wonderful.
I've built both. Main difference is B1 is single ended/Single Supply. Rev2 is push pull/dual supply. The caps aren't really a concern to me. Rev2 sounded more decisive and harder. Original B1 was more romantic and organic. But both probably sound pretty different from an active preamp if you are used to that. Personally, I am not a fan of no gain passive preamps...currently using the Korg B1.
@ibuski , Allow we to sing the praises of the B1R2, i.e. the bipolar supply version with complimentary matched JFETs. I've built more than a few pre-amps based on this buffer, with and without gain and with and without power supplies and they all sound very, very good. This little buffer gift from Papa is worth its weight in gold. I'm working on another variant as I write this. Build it and I am sure you will be very happy with what you hear.