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Ampeg SVT Classic with 410HE & 115E


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When it comes the world of bass amplification, aguably few others have the lineage and accolade of the legendary Ampeg Company -Stanley Micheal and Everett Hull's first bass amplifiers even pre-dated Leo Fender's electric 'Precision bass'. By the mid sixties, the distinctive 'Portaflex' series (most notably the B15) were (and still are, possibly?) the standard by which most other 'bass' amplifiers were measured - there were few products that were designed specifically for electric bass back then. Early examples such as the Fender Bassman 4x10 combo, the VOX AC50 / Foundation 1x18 and the Marshall JTM 45 with it associated 4x12 all worked but each had their own short comings. By the mid / late sixties, musicians were asking for more power and volume so in response, a number of manufacturers, notably Marshall amongst others had designed and built 100w amplifiers but Ampeg ripped up the rule book and presented a 300w amplifier at the 1969 NAMM show. Designed by Bill Hughes and Roger Cox, it was capable of playing clean and loud, had a reasonably comprehensive EQ that actually worked and was to be ordered with two(!) 8x10 cabinets tuned to roll the low end off a little earlier and at a smoother rate than the competion - there was no bump or percieved 'hole' at the bottom anymore. This was almost certainly the first high power, real bass amplfier and so, SVT rig had arrived..


Early examples (known as 'Blue line' due to the print on the control panel) seemingly had some reliability problems when they first went on tour with the Rolling Stones in US; a design issue in the driver stage caused the control grids of the 6146B output valves to be driven positive when pushed very hard. Prolonged use at high levels would eventually result in failed valves so during the tour, SVT amplifiers were occasionally swapped mid-show to keep the music going. Within a year, however, the SVT had been re-designed to use 6550 output valves with changes to the mains transformer spec and power supply rails which seemed to all but eliminate these faults - the Ampeg was to become a solid and reliable performer.


The SVT Classic (or CL) was introduced in 1994 as an up to date version of that original 'blue line' amplifier but with some useful modern additions. Most notably, a single input channel design with an improved EQ, sporting a 5 (up from three) position mid frequency control, user adjustable bias, and a balanced DI out to name a few. Several opinions over on the 'other bass forum' suggest some struggle to tell the difference between the 70's and more recently built units. Personally, I've never played through a vintage example although it seems even today, in the era of the modern and lightweight amplifier, the heavy iron, 6550s and useable EQ are still very much a winning formula. Despite being in production since the '90s, the CL is still available as a new product with very few changes throughout that time. Original Classics were built at St Louis Music in the US although production has also been in Vietnam, Korea and most recently China.




  • All valve design
  • 300w RMS at two or four ohms from 6x 6550
  • Baxendall style EQ with semi-parametric mid range
  • Additional 'Ultra Lo' and 'Ultra Hi' EQ switches
  • Active (-15dB) and passive jack inputs
  • Master volume
  • Patch points for pre-amp and power amplifier
  • Balanced DI (XLR) output
  • User adjustable bias


Front Panel:


There's nothing fancy on the largely black and white front panel, it's straight forward and un-cluttered - very much what you see is what you get here. Two jacks, two buttons, six knobs, an LED and two switches. Thats it!




Dual jack inputs on the far left are then followed by an input gain control - there's no indicator to show input level so judging it by ear is required. Two vertically stacked buttons engage the 'Ultra Lo' and 'Ultra Hi' which add a degree of 'boom' and 'ping' respectively. The active, three-band EQ is controlled by the following four rotary controls with bass, mid, mid-centre frequency (which changes the character of the sound) and treble controls. The final control is the master volume to control the output and DI level. On the front, there's little else of note other than a slightly noisy, centrally located cooling fan. At the far right are the mains and standby switches with an LED indicator showing the power or a fault status.


Rear Panel:


The Ampeg has an equally simple rear panel with an IEC connector for power, a polarity switch (which can help with hum - I've never had an issue) and the user adjustable bias controls for the power tubes. Arranged as a pair of controls, LED indicators show the status of each bank allowing the user to keep the 6550s within their ideal operating range over the lifetime of the set. In the middle is an unbalanced (jack socket) slave output (post master) for use as a line out. Further to the right is an XLR socket which is a balanced DI output allowing connection to a mixer or interface for both recording or reinforced live use. Patch points follow the DI with vertically positioned jack sockets for pre-amp out and power amp in connections. Towards the end of the panel, a recessed switch flicks between the 2 and 4 ohm taps on the output transformer with speaker connections at the far right sporting both conventional jack sockets and Speakon outputs. Above the panel, a grille protects the heavy transformers, driver and output valves - all engine room components are clearly visible.


SVT sunst




I have to admit, I expected it to be something of a 'one trick pony' simply doing 'the grunty Ampeg rock thing' but was actually very impressed with the scope and power of the straight forward EQ. That 5-position mid frequency control is the jewel in the crown of the SVT allowing significant character changes without altering the other controls. The Ultra Hi and Lo buttons are also very useful for character changes too - the Lo button seems to be more of a low-mid cut than any kind of boost and would suit those looking for a softer, warmer sound - by contrast, the Hi switch brings about a degree of bite and really seems to get the HF unit singing. Personally, I prefer to keep the lo switched out and the hi, in as I particularly like the influence it has on the sound. The big CL is very much a plug and play amp given it's straight forward presentation so even if a player is unfamiliar with it, a good sound shouldn't take too long to dial in.


As can be seen in the pictures, my example is used (pretty much exclusively) through the Ampeg cabs, namely a 410HE and 115E so any references to how it sounds (always difficult with words, I appreciate) are with influence of them, too. Whilst the basic identity of setup is quite low-mid heavy which works well for my tonal preferences, I would imagine the EQ has enough control to get most users in the ball park of their own sound. Personally, I use a bit of cut on the bass and mid-range with it on position 5 and leave the treble flat with the Ultra Hi in - it seems to work well enough with most of my basses. There's definitely some natural compression that occurs through the pre-amp stages allied to bit of the valve saturation in the sound too - niether are a bad thing in my book. If the gain control is turned fully clockwise, the drive isn't the sweetest - I find it a little 'edgy' and generally prefer the clean / saturated character. As a player, I'm more Stuart Zender than Lemmy. I do like to use my Digitech Dual Bass Squeeze with the setup (when I'm playing, at least) but feel it's not absolutley essential and for recording a rock sound with a player using a plectrum at the studio. Using the DI and / or miking one of the cabs gives super results with nothing being lost in translation.


It's funny, whilst the SVT does exactly what I thought it would, I'm genuinely impressed with just how flexible it is and how convincingly it turns it's hand to any number of other sounds.


The other thing these big-bottled-beasts are known for is their grunt and power. It's not lacking! The claimed 300w seems pretty genuine as the EHX branded 6550s play plenty loud enough before breaking up - by the time they do, it's a bit much, frankly. Even on a festival stage or the loudest of rooms, I can't really see the Ampeg running out of steam. I haven't gigged it yet but it's done plenty of sessions at the studio with most players loving it in an instant.




Build Quality and Reliability:


According to many online reviews over the last fifteen years or so, Ampeg seems to have gone through phases of questionable build quality and QC even before the bulk of  production was moved out of the US. Made from all Chinese examples built within the last five years, I bought 'the stack' from a chap who'd bought it all new but simply found it too heavy and bulky to move around. He'd clearly looked after it very well as it still looks new. There's very little to be critical of and irrespective of it's country of origin, both the cabs and amplifier are very well built throughout. Both wood-work and metal chassis / panels feel solid, all upholstery is cleanly and accurately finished along with quality fittings and hardware. All of the jack connectors, the XLR and Speakon all feel solid with a positive 'clunk' when plugging in; the rotary controls on the amplifier are firm without feeling stiff and all the switches have a heavy feel to them which is reassuring. Looking inside, JJ and EHX valves allied with (exceptionally!) heavy transformers are usual hall marks of a well engineered amplifier plus a sneaky peek behind the (removeable) front panel where the fan is mounted exposes heavy looking wires, chunky connector blocks and reasonably thick PCBs. It's probably fair to say the finish is less glamourous than that of my Trace Elliot V4 with it's ceramic sockets, gold-plated jacks, enamled panels plus it's fancy black, silver and green livery - the Ampeg doesn't have quite the same standard although it is no worse made than my other GP12-SMX based Trace amplifiers and associated cabinets. Arguably the difference between an '80s Mesa and a Marshall. My only slight criticism of the setup day-to-day is that front mounted fan as it's a bit noisy. I understand that air flow through the amp is essential given the heat given off by those big tubes but I'd prefer one larger fan running at lower speed on the rear panel like vintage SVT models although, it's far from a deal breaker.


Inside the cabs reside Eminence drivers - no complaints here. I've had no need to pull them apart but the 15" driver housed in the 115E is apparently based on a Delta Pro with a cast frame albeit de-rated to 200w whilst the 10" units within the 410HE are slightly less impressive pressed-steel frame drivers, probably variations on the standard range (also possibly Deltas?) with a 2" voice coil and a 125w rating - 500w for the complete cab. The 410HE also has the Fotex high frequency unit used by nearly all the other manufacturers and, much like my SWR cabs, it is well implemeted and adds a lovely sizzle. 


Having owned it since July 2022, it has been so far 100% reliable. It has done plenty of hours in service at the studio but arguably has had an easier life than most not being lumped in and out of sweaty venues or being stored in cold vans. Time will tell but it's currently not giving me any cause for concern.    


SVT 135


Other thoughts and observations:


As I've hinted at previously, this particular range of gear doesn't fit into the 'lightweight' category - quite the opposite. The SVT head is by far the heaviest amplifier I've ever owned at the best part of 40Kg (90lbs). Oddly, the cabs don't feel quite so bad and are roughly what would be expected for traditional boxes of their size loaded with conventional ceramic magnet drivers at about 30Kg (70lbs) and 40Kg (90lbs) for the 115 and 410 respectively. When lifting them, the balance of both the amp and cabs is generally pretty good with no arkward 'all the weight on one side' issues, handles in unuseable places or anything frustrating like that, thankfully.  


Since I started playing, I've pretty much only used Trace Elliot amplifiers in various shapes and sizes as they (give or take) do the sound I want without fuss. The V-Type needs a bit of help with an additional EQ unit but it really hits the nail on the head tone wise and is always my go-to. Being satisfied with my sound for the most part, I've never hugely lusted after an SVT or indeed anything else but as the owner of a studio, having an Ampeg option in addition to my existing Trace and Fender setups is pretty useful. Originally, I was looking for a V4BH as the pre-amp is identical to that of the CL so figured tonally, they wouldn't be a million miles apart with the added bonus of not having the monsterous weight or expensive replacement 6550 valves of the SVT. Sadly, I looked for a few months to no avail - here, eBay and Facebook turned up nothing. Eventually, I gave up on the V4BH and looked a bit wider deciding that an SVT was also an option. Having spotted this lot on FB, I hashed a deal out with the seller who was reasonably local (a lovely chap from Southport) plus the charm of the matching cabs proved to be irresistable. I spent twice what I was intending to but it's earning it's keep and is proving to be a hit so I guess it's money well spent.


The history of Ampeg is well documented, so much so, there's even been a book written on the subject (which is a great read, btw) so there's no need for me to re-tell the story here. What is worth mentioning is that Ampeg is now owned by one of the largest music companies in the world - Yamaha. Whether they'll feel the need to reinvent the brand with a new line of products in the coming years or will simply leave Ampeg to do their own thing remains to be seen but the all valve flagship models (SVT-CL and SVT-II) seem to still be firm favourites in post-pandemic 2022 - even against their own line of smaller and lighter PF series of amps and cabs. It's unavoidable to point out that both have been in production for a long while now with the original non-pro version of the SVT-II even pre-dating the CL and going all the way back to 1990. There's not many products in the industry that have managed sustain that level of popularity over such a long period of time so in my humble opinion, the SVT deserves legendary status alongside other classics such as the Fender Strat and Jazz Basses and the Vox AC30 amplifier - all time proven. 😃


SVT 135


It looks great, sounds great, is far more useable and versatile (assuming I don't have to move it!) than I would have ever given it credit for - a superb tool. 😃

Edited by VTypeV4
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On 24/10/2022 at 14:07, skidder652003 said:

Great review, love mine, despite the weight, its the "one"


When you find it, you find it! ❤️ I'm the same with my beloved Trace V4 but even if it weighed twice as much, it's still the one.


3 hours ago, Reggaebass said:

Really great review and a fantastic setup, I would have the same but it might be a bit much for my bass room at home now 😁


Thanks, man - it's awesome. 😃 As can be seen in the fourth pic, it lived in my living room for the first week or so. I'm sure a similar setup would look (and sound great!) in your bass room too! Ha. 🤣

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  • 7 months later...

Incredibly, it's been nearly 12 months since I went to sunny Southport to grab this lovely lot! I thought I'd share how it's held up.. 😃


In a word, it's been faultless and all the comments in the review regarding it's tone, character and general physical characteristics still very much ring true. The SVT and associated cabs have found many friends at the studio with around 75% of clients choosing to play through it - irrespective of genre.


Squier 40th


When recording, (for the most part, at least) I've moved away from the usual DI / Mic blend and now work a slightly convoluted system of taking 3 DI signals using a Trace SMX as an active line splitter / amplifier. One of these DI lines comes from the SVT and is one of the best sounding built-in direct outputs I've ever used. From memory, it's tapped very late in the signal path, either just before after the inverter / driver stage so all of the pre-amp character is present at the XLR socket with no wierd artifacts, noise or additional distortion. 


I haven't taken it out and gigged it - in fact, it's never even left the live room since I put it there so can't really comment on the Ampeg's gig-worthy-ness but being honest, I don't really need to, do I (!) 🤣 


In terms of reliability, again it's track record remains 100% with no faults, inconsistent performance or drop outs. Under my use, the stack doesn't tend to get driven particularly hard but it does work a lot of hours. Mark at the studio also makes use of the SVT and loves it just as much as I do - he reports lots of his clients also gravitate towards it.


I'm not sure if it's a current trend or the 'Ampeg is a standard' thing but as I said before, by a reasonable margin, the Ampeg rates very highly at the studio with the SMX Trace coming in a close second - I always let players try them all to make sure we're sonically on the same page. The borrowed Trace V6 usually comes in 3rd, a little behind the SMX but the old Bassman 135 doesn't even get a look in anymore - I really can't recall the last time I recorded with it. 


Personal waffling and thoughts aside, the SVT and it's cabs have certainly been a great investment at the studio. Whilst it seems unlikely the presence of a single Ampeg rig has won me any clients on that fact alone, it certainly hasn't done the reputation of the place any harm - long live the SVT. ❤️ 

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