Recording SVT output transformer comparo...stock vs. Heyboer

Apr 11, 2005
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So yesterday I got a second Heritage SVT rig:

IMG_0936_zpseebyxzoe.jpg


Yeah, I know.

The new one is bone stock while the old one from 2013 has a Heyboer output transformer spec'd on an original Blue Line transformer. I got the Heyboer after a couple discussions on here and some consultations with Ampeg employees who were very big on it. Been a great tranny and the price was right so I'm glad I got it. But since this new one is going to be a house amp at a couple venues we play regularly and available to other acts when we're not playing, I skipped the Heyboer. Of course, I AB'd them rigorously by ear for an hour when I first got the new one yesterday. I'm not so sure I hear any differences between the stock OT and the Heyboer (both have the stock JJ tubes all around), but then with the lag time between switching them out, sometimes I think I do hear slight differences but then I forget what the other one sounded like. All I can tell is they're very very close in tones and the stocker is no slouch at all.

So tomorrow I'm going to record them to try and get a better fix, but I have a couple questions about the best way to do it.

1. I'm going to record them with a Type 85 DI between the heads' speaker out and cab, but I'm wondering if I should also mic the cab. Seems to me to be rather pointless when the goal is hearing the amp as plainly as you can, no? I'm going to record samples both clean and with power tube distortion, but even for them, I think I'm better off recording them straight into my DAW. What do you all think?

B. Of course I'll let each amp warm up fully, but is it better to let them warm up for a couple hours vs doing it after about 15 minutes of warmup? Does it make much of a difference? We've pretty much decided that an amp is going to get about as warmed up as it's ever going to be after about 15 minutes, right?

Thx in advance for answering questions I should have known the answers to already :D But it never hurts to double check yourself when doing something this important.
 
I'd say if you want to be semi-scientific here you're going to have to do some work. Record a pass with a looper or direct into your DAW and use a reamp box. Track a pass with the countryman and a mic on one cab with one amp. Swap all the tubes from that amp into the other amp and set the bias, run again with the same cab, same mic/placement, and use the looped/reamped sample into amp two.

Or set them both up and just A/B between them for fun.
 
I'd say if you want to be semi-scientific here you're going to have to do some work. Record a pass with a looper or direct into your DAW and use a reamp box. Track a pass with the countryman and a mic on one cab with one amp. Swap all the tubes from that amp into the other amp and set the bias, run again with the same cab, same mic/placement, and use the looped/reamped sample into amp two
Oh, intercourse the penguin!

20fbdf116e7a5c798bbe86357675363f7f268468_full.jpg


Or set them both up and just A/B between them for fun.
Somewhere in the middle is the answer.
 
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So yesterday I got a second Heritage SVT rig:

IMG_0936_zpseebyxzoe.jpg


Yeah, I know.

The new one is bone stock while the old one from 2013 has a Heyboer output transformer spec'd on an original Blue Line transformer. I got the Heyboer after a couple discussions on here and some consultations with Ampeg employees who were very big on it. Been a great tranny and the price was right so I'm glad I got it. But since this new one is going to be a house amp at a couple venues we play regularly and available to other acts when we're not playing, I skipped the Heyboer. Of course, I AB'd them rigorously by ear for an hour when I first got the new one yesterday. I'm not so sure I hear any differences between the stock OT and the Heyboer (both have the stock JJ tubes all around), but then with the lag time between switching them out, sometimes I think I do hear slight differences but then I forget what the other one sounded like. All I can tell is they're very very close in tones and the stocker is no slouch at all.

So tomorrow I'm going to record them to try and get a better fix, but I have a couple questions about the best way to do it.

1. I'm going to record them with a Type 85 DI between the heads' speaker out and cab, but I'm wondering if I should also mic the cab. Seems to me to be rather pointless when the goal is hearing the amp as plainly as you can, no? I'm going to record samples both clean and with power tube distortion, but even for them, I think I'm better off recording them straight into my DAW. What do you all think?

B. Of course I'll let each amp warm up fully, but is it better to let them warm up for a couple hours vs doing it after about 15 minutes of warmup? Does it make much of a difference? We've pretty much decided that an amp is going to get about as warmed up as it's ever going to be after about 15 minutes, right?

Thx in advance for answering questions I should have known the answers to already :D But it never hurts to double check yourself when doing something this important.

First of all, bummer you have to spend a day recording 2 awesome giant amps, rough gig.

1) probably just the DI, and I'll bet there's almost no difference, other than an expected slight differrnce in amps. I bet neither is "better." Can you do a blind Poll on talk bass? As in, can you take poll answers but not let people know the results until it's all over, so as not to influence their decision?

I asked a guy at Radial once how much better the Jensens were than the fine Chinese ones they put in their lower cost gear. All he did was silently shrug his shoulders. Nuff said. Obviously OT's are operating on a much bigger scale but my prediction is the poll gets split pretty much down the middle.

B) no idea. I'd just turn em both on in the morning and let them stew for a while, think about what they've done.
 
Mmmm.....

I think it's a good call to mic the cabs. In a live setting, that's what you are getting so any tonal difference would need to be noticible emitting from the speakers.

IMO the FOTH will color any diffence pushed out of the head anyway. I think the real story here is what's coming out of your speakers.
 
First of all, bummer you have to spend a day recording 2 awesome giant amps, rough gig.

1) probably just the DI, and I'll bet there's almost no difference, other than an expected slight differrnce in amps. I bet neither is "better." Can you do a blind Poll on talk bass? As in, can you take poll answers but not let people know the results until it's all over, so as not to influence their decision?

I asked a guy at Radial once how much better the Jensens were than the fine Chinese ones they put in their lower cost gear. All he did was silently shrug his shoulders. Nuff said. Obviously OT's are operating on a much bigger scale but my prediction is the poll gets split pretty much down the middle.
I could do a blind poll, yes. Was debating on even posting my clips at all, but I guess some folks might be interested in it.

And regarding those Jensen transformers, Tony Levin did some recordings a few years ago with a bunch of different DI's, and two of them were Whirlwind Directors, one with a Jensen, one with a stocker which I assume was from China. I couldn't tell the difference.

B) no idea. I'd just turn em both on in the morning and let them stew for a while, think about what they've done.
Yeah, I'm probably overthinking that part. I just get impatient.
 
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Warm up the amps with standby off for at least half an hour. Use your ears to dial them in to sound the same at a lower volume. An RTA spectrum on a phone or pad will allow you to visually see any differences in EQ. You would be surprised to see what is going on. An app like this one, see the last segment in the video: Spectrum Analyzer for iPad, iPhone and iPod touch. The built in mic is fine in this case because you are using it to compare two amps relative to each other.

There are way too many variables to make this scientific. Test equipment would help identify differences. The app can help here. As Corey said, reamping will provide consistency. Normalizing the tracks within the DAW is important as even a slight volume difference can make one sound better than the other. There will be differences due to component tolerances, even with two identical amps and perfectly matched tube sets. Do the best you can with your ears.

When testing an output transformer, you want to listen carefully to the clean notes. How distinct they are, the quality of the notes, the harmonics. Listen for low end distortions. Then play chords and listen for distinct notes, smearing indicates distortion. Do some slapping using upper registers, listen for how the impulse is handled. Then repeat with the amp pushed into distortion.

The speaker cab affects the performance of the transformer. Adding a mic will create a whole new set of variables, exact placement on each cab is important. But since you can gather the data with a mic'ed cab, why not include it. Using the same cab for the tests would be ideal but this is the real world. Maybe swap the cabs with one head just to see if there are any sonic differences.
 
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First fo all: @JimmyM Congrats! \m/

One question about the OT comparison: That would require to have it played quite loud, right? Or does an OT have hearable coloration/influence on the sound at lower volume?

Just asking, since my first thought was A/Bing the live, as well; one rig to the left, one to the right - at reasonable volume. But at certain volume, I guess, the room would take over coloring the sound, masking any OT influence. Is that right?
 
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