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Discussion in 'Amps and Cabs [BG]' started by etherealme, Dec 9, 2020.
What are the differences in these preamps? Anyone have experience with both perhaps?
Here are the manuals
https://ampeg.com/support/files/Discontinued User Manuals/SVP-BSP/SVPBSP.pdf
The CL is a single channel, basically just the preamp from the SVT-CL. The BSP is two channels with overdrive and an effects loop.
Haven't used either. I had one of the SVP pros which were the newer version of this one, I think the SVT-II (and II pro) versus the CL. Sounded good, not as good as running the full SVT but sounded good.
https://ampeg.com/support/files/Discontinued User Manuals/SVT-IIP Pre-Amp/SVT-IIP Manual.pdf
The SVP-CL is supposed to be really close to channel 1 of the vintage SVTs. I have an 8-Pro which is supposed to use this preamp and it sounds a lot like my two vintage SVTs. The only control that does not sound quite right is the bass control. The specs say it's voiced at 20hz. The specs for vintage SVTs say the bass control is voiced at 40hz. If you compare the bass control on the schematics they are almost identical, so I don't know exactly what the difference is...but the SVP-CL sounds like it working at a lower freq to my ears.
I have never played a SVP-BSP, but it is very clearly different from an SVP-CL since it has two channels. One is set up for clean and one is set up for OD. Also the SVP-CL has two 12AX7 and two 12AU7s. The SVP-BSP has only one 12AX7. Obviously the circuits are very different and my guess is the SVP-BSP has quite a few solid state components in the signal path.
I have a SVP-CL and SVT-IIP and they sound similar and great.
I had read a post here years ago that the Sheehan was voiced differently.
Billy Sheehan sound employed multiple methods to basically have a clean channel and dirty channel.
And both channels use different compression settings and effects. So he usually needs effect send and returns for both channels. And uses different effects on both channels.
Anyways the Ampeg Pre essentially did this for him at the time. Both channels had effect sends. Both channels have separate DI outs.
He also liked intentionally doing phase inversion to get different tones. But usually his soundman did this on the board. Later he added these functions to his signature bass to run his clean or dirty out of phase.
Also his EBS signature pedal did the same.
The SVP CL is more like a actual SVT. With more tube stages. And has classic inductor based mid switch.
It also has another 5 position ultra low control which emulates. Older SVT low high cut switches and inputs. And very similar to " voice" settings on solid state combo amps.
Billy Sheehan has a sweeping mid that mimics the frequencies a normal SVT has. But he didn't care for the 200 or 3k settings. ( Agreed lol) so his signature is just a Opamp circuit you can sweep from 300 to 2k. Basically with the 5 position SVT mid.
It sweeps from position 2 to 4.
He also changed the range of the bass and treble knobs to a more ... usable range than the SVT.
Very different heads and voicings. But Billy has a good ear. It's a very straight forward pre amp. Just the separate channels, 2 effect loops and 2 DI outs are probably overwhelming for most. But incredibly useful. For dual rig sounds.
He actually used 15" speakers for pushing mids. And tended to over EQ a 410 for lows.
I think the features are closer to the SVT-5’s preamp then the SVT-CL
I am just now getting into Ampeg and analyzing their line which is a bit fuzzy after the 2000's - and that's just the tip of the iceberg of course.....
Anyway, follow up question:
Is the preamp in Ampeg's Portaflex Series of class D amps like the SVP-CL at all? I have tried the pf-800 so I am familiar with what that amp does. Would the SVP-CL be a similar approximation as far as function running into a power amp?
I am tempted to try the BSP but it lacks a sweep or any kind of variable EQ function....
I had the SVP-CL and now use a PF-800 . I used the SVP-CL with a Crown XLS1500 and it really sounded great . The PF 800 does sound close to what the SVP does and the controls are very close to the same . I don't feel like I left much on the table when I switched . The SVP had a richer sound , hard to explain , but the PF sounds very similar and live with a band I can't tell much difference at all , they both sound great to me .
The posts in this thread suggest the SVP-CL and SVT-BSP are two different animals, so I have having trouble following your logic pattern. How do you go from, "Would a PF sound like an SVP-CL" to "I am tempted by the SVP-BSP?"
Probably the biggest factor you need to consider is whether you want preamp drive or not. Based on my experience with my SVT 8-Pro, which has an SVP-CL based preamp, the front end is super clean.
I want to try an Ampeg preamp. Made my query clear in the last post.
Anyway, thanks for the informative portion of your reply. The various takes from users on different Ampeg preamps vary widely depending on interpretation. I have responses about the CL being "clear" but others have stated it depends on the user and how well you know how to use the pre, settings wise.
Also, as I stated before, the BSP sounds attractive for drive but lacks EQ functionality. Seemingly like a singular animal.
How does the early SVP Pro blue label pres compare with their five tube design? Those return hosts of problems, contacts coming loose with wear and distortion. It could just be that there are years of responses from various owners though...
Yes, it would be nice to have some drive. As I stated before, I don't want a one-trick pony though. The preamp in the portaflex line of class D amps gets grindy according to my first hand experience with that one. It's dark in nature which is actually pleasant and not a turn-off. I am just wondering if the "clean" nature of the CL is in that ballpark. Because if so, it's not relegated to just being defined by a "clear" character.
I have an SVP-CL (pre) and an SVT-CL and I agree.
Their inherent voicing is clear; and powerful as he11!
No matter what style of power amp, there is something going on with that big tube monster that kills.
I also have an SVT-IIP pre amp and class D and led sleds for power amps. They get, close and maybe you wouldn't here it in the crowd but I'm certain I can do a double blind test on stage and know the difference.
Here's the confusing part...despite the naming convention, the SVP-CL is not like an SVT-CL. It was intended to be channel 1 of the vintage SVT, with a few added features.
Re: New Ampeg Preamp
Also from the SVP-CL manual: "It is true to the design of an early-70’s SVT with the addition of modern tone-shaping and output selection."
The SVP-CL runs the signal in and out of 12AX7s and 12AU7s to get the original gain structure instead of running sequentially through the sections of 12DW7s. For those who don't know, the original amps used 12DW7 in channel 1. A 12DW7 has two triodes. One triode is like a 12AX7 and the other is like a 12AU7.
In a vintage SVT channel one has three 12DW7s and the two channels are mixed in a 6C4 which is essentially half of a 12AU7. So the types of sections come in this order. [12AX7, 12AU7 (V1)], [12AU7, 12AX7 (V3)], [12AX7, 12AU7 (V4) **], [12AU7 (V5)...remember this is a 6C4]
**This where channel 1 ends in the vintage SVT.
I believe the tube sections are used in the following order in the SVP-CL: V1a (12AX7), V2a (12AU7), V2b (12AU7), V3a (12AX7), V3b (12AX7), V4a (12AU7)**, V4b (12AU7). Notice the types of sections come in the same order as the vintage SVT.
The remaining section, V1b (12AX7), is used to drive the Post DI and it is taken off the output of V4b.
The SVT 8-Pro preamp is not exactly like the SVP-CL as it only has one 12AU7 and the SVP-CL has two. With the SVT 8-Pro, the original gain structure is not maintained in the second triode. The signal path goes from V1B to V1A (so both sections are 12AX7s). FYI, V1B is used first because a tube's second section has a slightly better S/N ratio.
So the SVT 8-Pro subs one 12AX7 for a 12AU7 and the back end of the preamp is solid state, which eliminates two triodes. Aside from the subbed 12AX7 section in the second section, the 8-Pro remains functionally consistent with the SVP-CL to the point marked with **. After this, the SVT 8-Pro becomes solid state. So all of the outputs except the Pre DI have solid state components in their signal path.
AFAIK, the SVP-CL does not have any solid state component in the signal path for any outputs.
My understanding is the SVT CL preamp is a bit more gainy than a vintage SVT or VR. In other words, it's designed to produce OD if you crank up the gain. That is one of the points I am trying to make. I believe the SVP-CL preamp has more headroom. Do you find this inaccurate? The preamp on my 8-Pro does not produce any sort of OD until it's pretty much wide open.
The SVT-IIP doesn't even have a master. I believe it's fairly close to an SVT II non pro...which is also based on channel 1 of the vintage amps.
Perhaps since the OP wants drive and flexibility, the SVP-Pro should be researched...AFAIK this is supposed to be the preamp for the SVT 2-Pro. Manual attached:
The SVP-Pro blue label is interesting and a strong consideration. What changed with the internals of the SVP-PRO when Ampeg changed the look of these from the blue logo to the above posted modern charcoal / black layout? Anything?
The SVP-CL is at our rehearsal space and I haven't seen in months.
It's driving an Ampeg SVP 1500.
Unfortunately the 1500 has an input sensitivity of 1.5 V and my early SVP-CL has a lower output. In other words when the volume is up high, it does not drive the power amp that loud.
OTOH, internal pre-amp distortion should be audible.
It's set for pretty flat EQ, master on full, and input volume at about 3:00 and it's clean.
If we ever get back to rehearsing I'd be glad to push the input volume up and master down.
It is driving a pair of ancient Altec 421's which don't want to see too much power.
I can try pushing my SVT IIP tomorrow as it's at home.
I would think that the SVP Pro is the way to go for distortion but have read many threads about them being noisy / hissy when the gain is up.
To the OP: These pre's are not that easy to find on the used market as they were not that popular when new.
Nice. I would have thought it was in the same ballpark but very good to hear from the horse's mouth!
The CL in SVP-CL should stand for CLean. It doesn’t seem to be for those who want built in OD, like the BSP.
Here's another data point:
SVT-IIP pre amp into GK MBF800 effects return to GB NeoX2x12; G&L JB
I normally run the gain at about 12:00 or 1:00
Gain adjusted by ear but it is clear this pre was not meant for distortion.
With the volume full up you could get some "hair" around the note, but as high as 4:00 it was still clean.
I would love to buy an SVT-IIP but they're pretty scarce.
I had the SVP-BSP and fed it into a QSC power amp. The clean channel was "boring" sounding. Not a lot of tonal adjustment and I felt like it was just "there". It had some of the Ampeg flavor in it, but not a very expressive sound. The upper mids were rolled off and it did not much going on with it. It worked well with combining the distortion channel though.
The Distortion side was FILTHY, buzzy, and mean. You could do some levels of overdrive, but it was basically mean sounding the entire time. I felt the entire unit was a one-trick pony. A good trick though! I saw Fear Factory in 2006 and the bassist at that time, Byron Stroud, was using this exact piece of gear. When I heard him live, the miked up tone was DEFINITELY this unit. Sounded awesome! For metal, this unit kicks butt. For a more expressive and adjustable tone, I suggest going a different direction.