OT Mic pre amp

[Burkeville]

HI,

Sorry this is off topic. Question for people that have used all tube gear.

I bought an old Ampex 4 channel mic pre built in 1960. I can't believe how good this sounds BUT I am finding it has a very wide dynamic range. There seems to be more contrast between the quiet and the loud sounds than when I use my API or my Drawmer 1960. Do other audio engineers notice this? It is to the point where I am using compression to the drive which I rarely do.

Experiences?

Oh BTW SAWSTUDIO sounds fantastic. I did a session (imported SAW files) on another system and really noticed a difference.

[Ian Alexander]

I just did a quick test here. It doesn't match any of your equipment, but pits a modern DW Fearn tube preamp against a solid state RNP preamp. I placed two identical mics in front of me and read a paragraph. After roughly matching the levels, I recorded 30 seconds.

On playback, I adjusted the pan a bit to balance L & R better. I could see very small shifts in the center of the "pan meter" on the Inspector meter, but couldn't hear any shifting.

I would conclude that any difference between left and right was due to response differences, not a difference in dynamic range.

Doubt this helps you much.

[Cary B. Cornett]

I bought an old Ampex 4 channel mic pre built in 1960. I can't believe how good this sounds BUT I am finding it has a very wide dynamic range. There seems to be more contrast between the quiet and the loud sounds than when I use my API or my Drawmer 1960. Do other audio engineers notice this?

I suspect that you are using the wrong words to describe what you are hearing/seeing. First of all, whether tube or solid state, the dynamic range of the signal coming OUT of the preamp is always EXACTLY the same as the dynamic range of the signal going IN. Did you perhaps actually mean to say "the tube preamp has a higher OUTPUT LEVEL"? This is quite possible, as the line amp stages of tube gear were commonly designed to allow peak levels of about +30 dBu before clipping, where most current solid state gear commonly clips at somewhere between +18 and +22 dBu.

It is to the point where I am using compression to the drive which I rarely do.

There is nothing inherently wrong with compressing the signal going in, but it is probably not really necessary. I'm guessing that your real problem is that you feel like you have to "fill the meter" on the Ampex unit while recording. If you really WANT to be compressing the input signal, fine, bit you CAN record without compression. All you have to do is to keep peak output levels within the range that keeps your Saw record level meters "happy".

The simplest answer is to simply IGNORE the meter on the Ampex box and rely strictly on the record meters in SAW. If doing that makes you uncomfortable, you may want to insert a 10 dB pad in the line between the preamp and your converter inputs, which will make the meters of the Ampex and SAW more closely "agree".

Please note that the Ampex meter reads AVERAGE levels while the SAW meters read PEAK levels. The Ampex meter will not register short-term peaks because the meter needle cannot move that fast (this is actually deliberate, BTW), so even if you got the different meters to "agree" on level for a steady tone, on real music they would likely not agree, especially on transient stuff like drums.

The correct way to interpret what you see on a mechanical VU meter is very different from how to interpret what you see on a peak reading meter. Making the best use of VU style metering is actually a skill that must be learned with experience. If you don't want to be bothered with learning it, there is no harm in basically ignoring the mechanical meter and relying on the peak meters in SAW.

As for the different "sound" of the preamp, all preamps are a little bit different from each other. You should be aware, though, that there is a definite difference between the technical idea of "a straight wire with gain" and "a great sound". Some engineers hold to the idea that the BEST preamp actually has no "sound" of its own, but should be completely transparent. It is not very difficult to build a mic preamp that is more transparent than your tube Ampex mixer (I have done this at least once myself). I'm not saying that your Ampex unit is "bad" or that you should not use it, just that you should be aware that you are using it to "color" your sound. The choice between "transparency" and "color" should be a conscious decision on your part, rather than just a "happy accident".

[Burkeville]

Thank you for your feedback.

The Ampex doesn't have any meters, I am just watching the SAW meters. I just notice that the level moves up and down farther than when I am recording with other preamps. I started engineering professionally in 1986 and have not had much tube experience.

Has anyone had this experience? Perry from Dark Horse maybe?

[Ian Alexander]

Thank you for your feedback.

The Ampex doesn't have any meters, I am just watching the SAW meters. I just notice that the level moves up and down farther than when I am recording with other preamps. I started engineering professionally in 1986 and have not had much tube experience.

Has anyone had this experience? Perry from Dark Horse maybe?

Have you tried putting two similar mics on the same source and comparing the levels from the Ampex and another pre?

[studio-c]

This all reminds me. I used to have an Ampex 2 track and a Scully 8 track, where each channel guts was in a 19" rack stack above the reels. Very 60s... Anyway, they all had mic inputs. I wonder if those pres were any good. They sure took up a lot of space. I gave all those decks away to a local tech who LOVED all that old stuff.

I can just see doing a music session using 8 mics going right into those 8 mic pres directly to 1" tape.

And now I'm remembering that it took three hands to do a punch in. You had to turn a knob up in the electronics stack then hit two buttons down below.

Makes me wonder about the pres though.

Hmm.

[DominicPerry]

This all reminds me. I used to have an Ampex 2 track and a Scully 8 track, where each channel guts was in a 19" rack stack above the reels. Very 60s... Anyway, they all had mic inputs. I wonder if those pres were any good. They sure took up a lot of space. I gave all those decks away to a local tech who LOVED all that old stuff.

I can just see doing a music session using 8 mics going right into those 8 mic pres directly to 1" tape.

And now I'm remembering that it took three hands to do a punch in. You had to turn a knob up in the electronics stack then hit two buttons down below.

Makes me wonder about the pres though.

Hmm.

I have a Teac 3340S with four mic pres and I can promise you that they are definitely no good. People managed though.

Dominic

[Bill Park]

This all reminds me. I used to have an Ampex 2 track and a Scully 8 track, where each channel guts was in a 19" rack stack above the reels. Very 60s... Anyway, they all had mic inputs. I wonder if those pres were any good. .

No.

And you can buy them at just about any electronics fleamarket for $25 a piece. I had one thinking that it might have a cool vibe, but in the long run it just sat there taking up two rack spaces.

However... there are some little jems from people like JBL, and even today the plug in transformers alone can fetch a couple of hundred dollars each. I had a JBL mixer I was using as a pre. I had the chance to work with Don Pearson, and -he- told me about them as lost jems... he cracked up when I told him that I had one.

Bill

[Tim Miskimon]

I have a Teac 3340S with four mic pres and I can promise you that they are definitely no good. People managed though.

Dominic

Actually I got some good bass sounds pluging a Fender bass right into the input of the 3340 - no eq - it was a pretty good match impedance wise.
I still am amazed at some of the bass sounds I got on those early recordings I made with that setup.
I guess anything is possible if you keep trying...

[DominicPerry]

Actually I got some good bass sounds pluging a Fender bass right into the input of the 3340 - no eq - it was a pretty good match impedance wise.
I still am amazed at some of the bass sounds I got on those early recordings I made with that setup.
I guess anything is possible if you keep trying...

The bass on everything sounds good on the 3340 - bass on vocals, bass on drums, bass on guitar. It just thickens everything up. Nice. But not real. And the hiss just from the line level circuits, in and out is terrible, even before the tape starts going round. But I do love the way it goes round.

Dominic