WTB: the best passive preamp there is.

anubisgrau · « **Reply #80 on:** 7 May 2010, 11:28 pm »

Quote from: Dracule1 on 7 May 2010, 11:08 pm

Just wanted to revive this thread because this attenuator caught my interest. Was this buffered passive pre ever produced?

well, definitely - you should check www.myth.rs

ASi_TEK · « **Reply #81 on:** 7 May 2010, 11:51 pm »

I wonder how that myth would sound with ultra low impedance battery power fully powering the units circuits and remove the ac mains and internal power supply totally (if possible). I tried this on a LDR from DIY Paradise, the Eva, and the results were unbelievably better across the board. LDR seems touchy to ac mains distortions. The Eva was kinda touchy, sometimes it would go nuts and I would have to reset it but maybe that was a bug that needed a fix in the programming that was fixed afterwards but it did sound fabulous. Bettered other TVC's I have used in the past, some costing well over $5K with buffers and special battery supplys. This could also be related to a impedance differential that occurs from component to component that another poster had mentioned. If thats the case, you could get the tvc's primary/secondarys impedance changed to be more suitable by the manufacturer if they willing do that on a custom basis , instead of adding in additional compensation circuitry afterwards into the already very sensitive analog line level domain.

Mariusz · « **Reply #82 on:** 8 May 2010, 12:07 am »

No affiliation - buddy send me this link.
Looks solid and input switching.

clink here to see classified ad

anubisgrau · « **Reply #83 on:** 8 May 2010, 10:26 am »

Quote from: ASi_TEK on 7 May 2010, 11:51 pm

I wonder how that myth would sound with ultra low impedance battery power fully powering the units circuits and remove the ac mains and internal power supply totally (if possible). I tried this on a LDR from DIY Paradise, the Eva, and the results were unbelievably better across the board. LDR seems touchy to ac mains distortions. The Eva was kinda touchy, sometimes it would go nuts and I would have to reset it but maybe that was a bug that needed a fix in the programming that was fixed afterwards but it did sound fabulous. Bettered other TVC's I have used in the past, some costing well over $5K with buffers and special battery supplys. This could also be related to a impedance differential that occurs from component to component that another poster had mentioned. If thats the case, you could get the tvc's primary/secondarys impedance changed to be more suitable by the manufacturer if they willing do that on a custom basis , instead of adding in additional compensation circuitry afterwards into the already very sensitive analog line level domain.

well my technical knowledge is crap but you are on the right track - i have myth LDR and i had it upgraded a few times already by the manufacturer. AFAIK these has always been changes in the PSU and the improvements were not that small at all, even going from panasonic to kendall caps made sound smoother and more dynamic. and i'm sure there's more to go, but i can't get them trying battery power. though, it doesn't have to be - i was recently invited to a demo of their DAC and AC powered version was clearly superior to SLA battery.

Dracule1 · « **Reply #84 on:** 9 May 2010, 07:58 am »

Anubisgrau thanks for the link. I noticed you also use the Bent Tap X which I am seriously considering putting together. What are the differences in sound between the Myth and Tap X?

anubisgrau · « **Reply #85 on:** 9 May 2010, 10:21 am »

well after having it for several months i'm not too happy with my TAP-X and i am even not sure if my piece is technically OK because it sounds very different to a simple, 1 input 1 output passive preamp based on the similar dave slagle autoformers which is probably the best (non bufferred) passive device i've heard. i have no explanation for that except that relays used for selecting inputs are doing something strange there

shortly: myth has a clear edge on transparency, drive, dynamics and bass quality but i think you can hear a sonic stamp of j-fet buffers (though i've just heard they might have a improved version).

TAP-X has a slight edge on tone - it sounds smoother and more polished but more reserved. i also prefer TAP-X looks because i like smaller boxes.

Dracule1 · « **Reply #86 on:** 9 May 2010, 12:08 pm »

Thanks. I know a guy who uses the Tap X and claims you really need to use interconnects 1 meter or less between the preamplifier and amp or you start losing dynamics. This is despite claims by others that autoformers are less sensitive to cable length than resistor based passive. Also if your source impedance is around 50 ohms or less helps too. I do trust his hearing and he knows a lot about electronics. What length cable do you use and do have any idea of the output impedance of your source? Have you talked to John Chapman at Bent Audio about your dissatisfaction? He is a very helpful guy and responds to email quickly.

You can here some transistor sound from the Myth? That's unfortunate. How are they going to fix that?
The only problem I'm having with the Myth is it only has one set of output. I need two preferably three. I emailed the company about it. Also I'm in the US so I need 120v version. The website only indicates 240v european version.

anubisgrau · « **Reply #87 on:** 9 May 2010, 12:12 pm »

my ICs are 1.2m hitachi LCOFC copper - i tried shorter but there's no difference in cruical aspects.

i have three digital source options - 50, 100 and 2800 ohm. the first two sounds good while the last one has a lack of control in the bass. slagle's a-formers can be restacked to suite the source's impedance, however if i remember correctly, it's not recommended to have a source with above 600ohm impedance.

Dracule1 · « **Reply #88 on:** 9 May 2010, 12:23 pm »

Well seems like you have your system set up correctly. Bent Audio does make a single input, single output Tap X that does not use the relays. But my understanding is it does not sound different than their multiple input version. I'm really wondering if your Tap X is functioning correctly.

Dracule1 · « **Reply #89 on:** 9 May 2010, 12:28 pm »

Are you in Serbia where the company is located? You seem to have good access to latest revisions of the Myth. How are they going to get rid of the Jfet transistor sound? I am very sensitive any hint of transistor sound.

anubisgrau · « **Reply #90 on:** 9 May 2010, 12:43 pm »

yes i am - that's why it was so easy for me to get a few upgrades from them. i also tried to help them with my comments because i changed so many preamps in my room before i settled with the passives and i think i know what are the usual mistakes (soundwise). i've had promitheus TVC, bent 102 TVC, music first copper TVC and now TAP-X, DIY-ed slagle AVC and myth.

AFAIK the latest mods include using some new JFETs instead of usual suspects, simplified schematics and better PS. i should hear this soon as they invited me for a demo of their new DAC. i will report.

of course it would be the best to avoid buffers but i'm afraid it just doesn't make sense to run LDRs unbufferred. the output impedance is so variable depending on attenuation and anyway so high that it makes it really difficult for matching.

i'm also a tube guy (i run horns with 10Y sets) however i have more and more evidence that tubes are not necessary everywhere. i'm totally fine with my two non tubed DACs (altmann and twinDAC+) and with my RIAA (pass pearl/ono - very surprising after living with a number of tube phono preamps with SUTs). that said i would love to hear a proper tube buffer (a la allan wright's super linear cathode follower), i think this may be the winning card. but i can't get myth people to build something along that.

Dracule1 · « **Reply #91 on:** 9 May 2010, 04:11 pm »

We have very similar taste in DACs. I like NOS DACs using the old Philips TDA 1543 and 1541 chips. Please let me know how the latest revision of the Myth preamp sounds. I will get the TAP X, and will try out the Myth if you feel that the latest revision gets rid of the slight transistor sound you mentioned. Thanks for your input.

doug s. · « **Reply #92 on:** 9 May 2010, 04:34 pm »

i am getting excellent results using my diy paridise eva-2 (eva is nla) as a remote wolume control between my tube preamp and amps. i am actually enjoying the sound more than w/o it; perhaps this is cuz the preamp likes operating w/its pots ~85% wide open? i have no issues w/noise/etc., from the eva-2; it is plugged into a balanced power conditioner...

doug s.

rajacat · « **Reply #93 on:** 9 May 2010, 04:41 pm »

How about battery powered tube passive pre.?
http://doddaudio.com/BatteryPoweredTubeBufferPreamp.aspx
-Roy

Dracule1 · « **Reply #94 on:** 10 May 2010, 02:06 pm »

anubisgrau, can you tell why you are not so happy with the TapX? You say it sounds different than your single input DIY Slagleformer preamp. In what way? Thanks.

anubisgrau · « **Reply #95 on:** 10 May 2010, 02:37 pm »

it doesn't have the sound like the same device as it should, considering the same a-formers inside. less transparency, less extension in bass, more reserved sound.

truth to be told i don't know what stacking is in both units - and that may affect the sound in a very big way

i have no time to investigate tap-x in more depth, but i'd also love to resolve a mystery why a simple 1 input 1 output AVC in a wooden box sounds so superior - and i found that only when i got used to a remote control of tap-x

shep · « **Reply #96 on:** 10 May 2010, 03:00 pm »

" No affiliation - buddy send me this link.
Looks solid and input switching. clink here to see classified ad " That's a lovely piece of kit. I wish I needed it

I would buy it anyway if... I have a buffered, stepped passive stage in my amp. Couldn't be happier.
Pretty much the same topology and parts as in the one in the ad.

Dracule1 · « **Reply #97 on:** 10 May 2010, 05:06 pm »

Anubisgrau, that's very interesting that you can hear such significant difference in sound between the DIY and Tap X. I was wondering if you have the buffered version of the Tap X. Some Tap X came with built in buffer that could be switch in or out of the passive circuit. Some say the buffer increases the noise level of the passive circuit, and the buffer when activated does sound much inferior to the pure passive mode. Anyway, thanks for your input.

Sonny · « **Reply #98 on:** 10 May 2010, 06:27 pm »

Quote from: anubisgrau on 10 May 2010, 02:37 pm

it doesn't have the sound like the same device as it should, considering the same a-formers inside. less transparency, less extension in bass, more reserved sound.

truth to be told i don't know what stacking is in both units - and that may affect the sound in a very big way

i have no time to investigate tap-x in more depth, but i'd also love to resolve a mystery why a simple 1 input 1 output AVC in a wooden box sounds so superior - and i found that only when i got used to a remote control of tap-x

Are you saying your 1 to 1 DIY Passive is better than the autoformer tap x?

anubisgrau · « **Reply #99 on:** 10 May 2010, 09:03 pm »

Quote from: Sonny on 10 May 2010, 06:27 pm

Are you saying your 1 to 1 DIY Passive is better than the autoformer tap x?

yes - bear in mind that the passive pre is also based on slagle´s autoformers just as tap x. can´t say if they are the same but both are slagle´s for sure. that´s what confuses me. i guess it would be far too complicated to exchange a-formers between the units to see what would happen then. it could also be some mismatch i´m not aware of at the moment.