Premier Rock Forum

>>I didn't know there was a transformer coupled version.

i asked around to make sure i'm not crazy

i may be crazy, but he did make one w/an output transformer option, i guess

>>I'm interested in your comment about the Syteks not having enough low end to record your bass. It's my understanding that transformers limit bandwidth, and the Syteks being transformerless, it would seem that they would work nicely with low freqs.

from makin' records etc., i recall preamps w/input transformers having 'better' low end than those with electronic inputs, and talking to steve about it a bit confirms my recollection.

don't know why, exactly. technically, transformers limit bandwidth, but i don't think they don't need to cause problems if they are good ones. it could be that the LF distortion of the transformers is actually enhancing the low end somehow. or that they just present a better impedance match to some random input than an electronic front end does. or that their ltd. bandwidth whacks out subaudio stuff and therefore the electronics doesn't have to deal with it and is left free to work on useful frequencies. don't know! but iif i find anything more out, i'll post again.

tmidgett wrote:technically, transformers limit bandwidth, but i don't think they don't need to cause problems if they are good ones. it could be that the LF distortion of the transformers is actually enhancing the low end somehow. or that they just present a better impedance match to some random input than an electronic front end does. or that their ltd. bandwidth whacks out subaudio stuff and therefore the electronics doesn't have to deal with it and is left free to work on useful frequencies. don't know! but iif i find anything more out, i'll post again.

No, I'm fairly certain it's not a bandwidth issue as most of the Jensen transformer spec's show them as utterly _FLAT_ down to 2Hz. I believe it's due to the core of the transformer becoming "saturated". Lower frequencies move more current through the transformer and the core can only handle so much current so it "saturates". I'm making a big leap here but I believe that saturation of the core is similar to the natural compression/limiting that happens in overdriven tubes or "saturated" tape. Now that my explanation probably violated all sorts of rules of physics I'd better let an Electrical staff-dude handle it...

number of times any of the sytek mute buttons were used during last session: zero.

StevenMallory wrote:No, I'm fairly certain it's not a bandwidth issue as most of the Jensen transformer spec's show them as utterly _FLAT_ down to 2Hz. I believe it's due to the core of the transformer becoming "saturated". Lower frequencies move more current through the transformer and the core can only handle so much current so it "saturates".

There's a difference between the pass band of the transformer (which is a design function, but can vary with source and load impedances and capacitances) and the power bandwidth (also distortion-limited bandwidth). These vary with core material, core mass and lamination type, thermal performance, core gap (if any), DC vs AC current, etc., and the results will be application specific.

The same transformer might perform acceptably in one application (low power, no DC, good thermal dissipation, non-critical distortion criteria) and have "limited" bandwidth in another application (more critical distortion criteria, DC offset, higher power handling, poor ventilation or heatsinking).

Microphone or phono preamp transformers can have very wide bandwidth and low distortion at the millivolt level, but would distort (momentarily), limit bandwidth and catch fire if used as power amp output transformers.

Properly implemented, transformer cores shouldn't saturate in normal use, but could in extreme circumstances.

A transformer (like anything else) can be "good" or "bad" depending on implementation. Transformerless design can be more easily half-assed, but excellent performance can be had in either paradigm.

Cases in point:

Transformer-input/output mic preamp (John Hardy M1/ M2): Exceptional bass performance.
Transformerless mic preamp (GML): Exceptional bass performance.
Transformer-input/output mic preamp (Ampex 351): Exceptional bass performance.
Transformer-input/output mic preamp (Ampex MX35): Not so much with the bass.
Transformerless mic preamp (Sytek): Not so much with the bass.

best,

.

justinc wrote:number of times any of the sytek mute buttons were used during last session: zero.

the mute buttons are used in every session I do. It's a nice feature when firing up phantom power (especially on the Earthworks which make moster pops when turned on or off), or turning it off. Also when changing out microphones.