Service Centre for Jackson Ampworks in Australia

February 22, 2014
Jackson Ampworks 'Britain'

Jackson Ampworks ‘Britain’

Hello, welcome back to the blog. We are now offering world-class (non-warranty) service & repairs to the range of valve (tube) amplifiers from Jackson Ampworks of Keller, Texas USA. We should point out that we have no official relationship with Jackson Ampworks, so we cannot accept any warranty repair claims without the endorsement of their Australian distributor.

Jackson Ampworks 'Britain' amp head

Jackson Ampworks ‘Britain’ amp head

We recently serviced the Jackson ‘Britain’ amp for one of our customers, who is a guitar tutor and professional player – the amp is featured in the accompanying photos. The Jackson amps are built in Texas, but are British-voiced. The concept of the Jackson ‘Britain’ is broadly similar to our own Richards ‘Expressionist’ amplifier models – there are two discrete preamp channels, voiced as per vintage VOX amps.

Jackson 'Britain' rear panel removed

Jackson ‘Britain’ rear panel removed

CH-1 is based on the EF86 pentode preamp valve (tube), and CH-2 employs the more familiar 12AX7/ECC83 valves and is effectively the top-boost channel. The EF86 is famously rather prone to microphony in guitar amps, but sounds absolutely wonderful in the right situation. The ‘Britain’ power amp section is switchable between a pair of cathode-bias EL84 valves for low power, and a pair of fixed-bias EL34 valves for full power.

Jackson 'Britain' chassis

Jackson ‘Britain’ chassis

The Jackson amp is very compact – about half the size of most comparable amps, ie amps in the 30 to 50 watt range. This amp depends absolutely on forced-air cooling for its survival, so if the fan ever stops working the amp needs to be serviced a.s.a.p. Some of the amp functions normally carried out by passive components appear to be implemented with the use of solid-state devices, which are mounted to vertical heatsinks, also in the forced-air cooling path.

'Britain' chassis: front view

‘Britain’ chassis: front view

Fortunately, for this service job there was nothing more serious than some noisy valves, which we replaced accordingly with a full check & test. The only problem we encountered was that the light aluminium chassis was quite resonant, at a frequency that was very close to the resonant ring from certain brands of EL34 power output valve that we tried in the amp. This was so noticeable that we substituted several brands before settling on the least resonant combination.

Jackson 'Britain' underneath the chassis

Jackson ‘Britain’ underneath the chassis

Finally, we were happy with the end result and our customer was pleased to get his amp back, working correctly again with unwanted noise at a minimum. You can see from the photo to the right that the amp is indeed hand-wired and the chassis layout is very tight indeed. Access to some components is limited or not possible at all without stripping out the electronics from the chassis.

Jackson 'Britain' chassis

Jackson ‘Britain’ chassis

Hardware components are by Carling, Switchcraft, Alpha and others – the standard of electronic components is also good. So there we have it – our very first experience of servicing the Jackson Ampworks product ! These amps look and sound great, but are relatively new to the Aussie music industry so we cannot pass any comments with ref to long term reliability issues. If you are in New South Wales and own a Jackson amp that needs servicing, please contact us @ ivan@ivanrichards.com

another Morgan amp in our workshop

January 27, 2014
Morgan RCA35

Morgan RCA35

Welcome to our first blog for the year 2014 ! Another Morgan amp came to our Wyoming workshop for repairs a while back – this time the RCA35 model. We previously discussed repairs to the Morgan SW50 back in January 2013. The RCA35 is voiced quite differently to the SW50, and is intended to be a ‘clean headroom’ amp, according to the Morgan website. A pair of cathode-biased 5881 output valves delivers 30 watts output @ the onset of clipping.

Morgan RCA35

Morgan RCA35

Our good customer, Josh, had purchased this amp about 6 months previously and advised us he was getting some very strange sounds, almost like an octave-fuzz pedal. At our first attempt to diagnose this, the RCA35 behaved perfectly so we were none the wiser. This situation happens sometimes ! After Josh got the amp back home again, of course it played up immediately, so he recorded the sounds on his ‘phone & sent them to us, and indeed the amp sounded like there was an octave fuzz pedal happening.

Morgan RCA35

Morgan RCA35

Back in the workshop, I strongly suspected that this degree of amp instability must surely be down to a faulty electrolytic capacitor (or capacitors) in the amp’s high voltage power supply. Josh was preparing to head off for a short tour in central western New South Wales with a band, so we couldn’t take the risk of leaving an intermittent fault in the amp. Therefore we took the decision to replace all four HV (high voltage) power supply caps, plus the cathode bypass cap for the output valves, just to be sure.

Morgan RCA35

Morgan RCA35

You can see from the photos that the original capacitors were of standard consumer electronics quality, and of recent production. There were no tell tale signs of leakage or faulty manufacture. We installed a set of those very fine F&T capacitors, bedded down in some silicone (neutral cure) for stability. Sprague ‘Atom’ capacitors would also be an ideal choice although their larger physical size sometimes limits their application in service work. The list of capacitors reads as follows: 2 x 30uF/500V, 2 x 22uF/500V plus 1 x 100uF/100V.

Morgan RCA35

Morgan RCA35

We also tightened a loose fuseholder and changed the fuse size from 2 amp to 1 amp as in Australia our mains power is obviously 240V (sometimes higher), and labelled the rear panel accordingly. The manufacturer and their local distributor really should have taken care of that particular issue. With the high voltage supply reading +430V DC, we measured 15.6V into 8 ohms = 30 watts @ the onset of clipping. We were pleased to hear that Josh got through his tour OK and there were no further problems with this amp !

Morgan RCA35 original HV capacitors

Morgan RCA35 original HV capacitors

Morgan RCA35 upgrade caps installed

Morgan RCA35 upgrade caps installed

Margan RCA35 after completion of repairs

Morgan RCA35 after completion of repairs

Ivan’s new Hame 1×12 cab

December 13, 2013
Hame 1x12 cab

Hame 1×12 cab

Hello & welcome back to our blog. Occasionally our customer amplifier projects require the input & support of a specialised cabinet builder, for work that is beyond our amp building workshop’s resources. For example, we have utilised the unique cabinet building skills of Mr Peter Davies (ex NSW Central Coast, now resident in Melbourne) several times for our exotic hardwood cabs.

Hame 1x12 cab

Hame 1×12 cab

More recently we have enlisted the help of Mr Brandt Horrocks of Hame Speaker Cabinets (Wagga Wagga NSW) to produce a pair of specialised 2×12 cabs for baritone guitar stylist, Mr Chris Earle. As a spin off from that project, Chris also ordered a pair of somewhat more compact 1×12 cabs, one each for Chris & Ivan, for rehearsals & lounge gigs. We will look at the 2×12 cabs in greater detail in a later blog, as part of the broader Chris Earle project.

Hame 1x12 cab

Hame 1×12 cab

This 1×12 cab design is a much simplified version of the original 2×12 cab design, which included angled speaker baffles. In both cases, the cab design allows sound to pass through vents on either side of the cab. These vents are not tuned, as in a “bass-reflex” system (ie, the cab is “de-tuned”). Sound emanates from the sides of the cab much as it would from the rear of an open back cab, while providing better dispersion & more consistent tone from venue to venue. In the 2×12 cab design internal angled reflectors push the sound from the rear of the speakers to the side vents.

Hame logo

Hame logo

The end result is a speaker cab that is never “boxy” or “boomy”, with outstanding dispersion, clarity & a solid low-end. The intended companion amp for Chris Earle’s 1×12 cab is a brand new model from the Richards Amplifier Company – Australia: the KT88se, ie a single-ended/class-A KT88 amplifier. This amp will be part of the “British Lead” series, meaning that the front end is voiced as per some of the classic amps from the golden-age of British rock. This amp is the result of months of R&D during 2013, & will be the subject of a future blog.

the pair of 1x12 Hame cabs under construction

the pair of 1×12 Hame cabs under construction

Please take the time to check out these photos of the new cabs. Regards – IR.

under construction

under construction

completed

completed

completed

completed

completed

completed

2x12 cabs completed

2×12 cabs completed

MODs to the HIWATT 20H amplifier

December 10, 2013
HIWATT 20H

HIWATT 20H

Recently we implemented some home-grown MODs to a HIWATT 20H amplifier for Rick Altavilla, now on guitar for home-grown Central Coast band Sparrows – fronted by the one & only Scotte Woods (formerly of One Dollar Short). Rick purchased this amp new, fully expecting that it would sound like a scaled-down version of the great original HIWATT amps. Unfortunately it sounds & performs nothing like an original HIWATT. This is not a cheap amp either – it’s actually a rather expensive one, even allowing for the fact that it is hand-wired from the UK. To say that the guys from Sparrows were disappointed with this amp would be an understatement.

HIWATT 20H

HIWATT 20H

The 20H has some design problems in common with the Marshall C5 discussed in our previous blog. Much of the available gain is thrown away due to some bizarre design choices and the 3-band passive EQ just doesn’t work at the desired guitar frequency ranges. Indeed, the 20H sounds really flat.

Basically, you could consider this amp to be a kind of modern AC15, with a couple of sequential gain stages, a buffer stage driving the EQ, a pre-PI stage master-volume, and a zero negative feedback power amp employing a pair of cathode-bias EL84/6BQ5 output valves. Such an amp design potentially should sound mighty fine.

HIWATT 20H

HIWATT 20H

The power amp & PI (phase-inverter) stage were OK – no apparent problems there, so we concentrated our attention on redesigning the preamp, within the constraints of the existing electronics & layout, to achieve a useable amp. We reconfigured the gain stages to get some drive & balls from the amp, & revoiced the EQ as per the C5 to achieve a useable & effective sweep from all controls. The 20H now sounded like a baby “British” amp from the 60s golden-era, which is not a bad result at all !

Thanks Rick & Sparrows. IR.

MODs to the Marshall Class 5 amplifier

December 5, 2013
the modded C5

the modded C5

Welcome back ! Over the last couple of years, in our blog pages we have presented MODs to the Marshall JTM600/JCM600 amps, Peavey Valveking 100, Fender Pro Junior & Blues Junior, Laney LC30, amps by Rivera, bass amps by David Eden, plus wah wah pedal MODs. We offer all these MODs and more here in our Wyoming workshop.

Marshall Class 5

Marshall Class 5

In the coming weeks we will publish a blog re our home-grown MODs to the HIWATT 20H valve amp head, which is a seriously disappointing amp (sorry about that, HIWATT !). But our latest MOD project to present to you is the Marshall C5 amp. These amps have sold really well in OZ due to a very reasonable price point for a made-in-UK Marshall with an all-valve (tube) signal path.

Marshall C5

Marshall Class 5

Unfortunately, the C5 straight out of the box is not an amazing sounding amp. The 3-band tone controls do not seem to have a particularly effective sweep, and especially not at the frequencies you expect from a Marshall (ie, the “Plexi” or “Super Lead”), plus due to the absence of a master volume control or attenuator – 5 watts is still too loud in some home playing or recording situations.

C5 chassis with original transformers

C5 chassis with original transformers

We agreed to implement the full range of possible MODs to this C5 for our customer, to transform the amp from a just OK unit into a high performance tone machine, with the option of turning down to conversation levels with the addition of an attenuator (controlled from the front panel).

C5 chassis with mercury Magnetics transformer set installed

C5 chassis with mercury Magnetics transformer set installed

Mercury Magnetics have developed a transformer set specifically for upgrading the C5, which comprises power transformer, filter choke & audio output transformer. Our customer requested installation of the full set. The addition of a filter choke will improve the performance of this Class-A/single-ended design significantly.

C5 chassis after mods

C5 chassis after mods

Other C5 MODs that we recommend include (in no particular order): raise input impedance R20 & remove C10, change cathode bypass cap C8 for tighter/plexi lows, add a (subtle) ‘bright’ cap across VR1, change ‘bass’ EQ cap C20 to implement a useable (plexi) sweep, change ‘slope’ resistor R28 for a more balanced (plexi) sound, change signal path caps C2 & C5 for improved lows & low-mids.

C5 p.c.b. connections & installing the VVR module

C5 p.c.b. connections & installing the VVR module

There are several other potential MODs which will have a less significant effect. The law of diminishing returns starts to kick-in. Note that all the above modding requires removal of printed circuit boards (p.c.b.’s), and changes to p.c.b. connections. The final MOD to this amp is the installation of a VVR module, available commercially on-line, to compensate for the lack of a master-volume or attenuator on the C5.

C5 p.c.b. connections- looking to the rear of chassis

C5 p.c.b. connections- looking to the rear of chassis

The VVR (Variable Voltage Regulator) is a relatively simple circuit that when installed in an amp such as the C5, will make the high voltage DC supply (usually referred to as HT, HV or B+) continuously variable from the maximum normally available from the amp’s existing power supply, to a minimum level which is preselected by changing resistor values on the module. In other words, by electronically varying the high voltage supply within the guitar amp, we succeed in reducing the audio power output of the amplifier from its design maximum to a preset minimum.

the VVR module requires 2 x additional chassis holes

the VVR module requires 2 x additional chassis holes

The VVR module employs a high-voltage power Mosfet device such as the NTE2973. In most cases it will need a heatsink, and ref the C5 bolting the Mosfet to the chassis is quite adequate. Thus we will need to accurately drill/punch 2 x additional holes in the C5 chassis – 10mm for the VVR control mounted conveniently to the front panel, plus 3mm for mounting the Mosfet, which must also be insulated from the chassis.

C5 front panel - the VVR control installed

C5 front panel – the VVR control installed

It just happened that a convenient place to install the VVR control is right where the Class 5 logo appears. It doesn’t look too bad actually, and our customer was happy with that, however it is an issue to take into consideration. We didn’t have any suitable Marshall-style control knobs to suit, so we ended up using a small “chicken-head” knob from Cliff.

Any of the power amp attenuation devices such as the VVR or London Power Scaling (for example) will solve the problem of reducing power for playing in the home, as will speaker attenuators such as the THD Hotplate & so on, in the latter case the amp still runs at normal power levels but the output is attenuated before it reaches the speaker. In spite of all the hype about some of these devices, they DO have a quite noticeable effect on tone & performance – it’s inevitable ! By definition, reducing the available voltage to the valves (tubes) will impact on dynamics & tonality – the various types of output valves in common use in guitar amps will sound & behave differently at different B+ voltage levels. Lower voltages particularly impact on the low frequency response of a given amp design.

We are happy to install devices such as the VVR in your amp (where appropriate) – just keep in mind that there is a trade-off.

By the way – our customer just loves his upgraded C5 amp now ! IR.

Warning !

While the VVR described above is a simple circuit it is not a simple MOD to install. It should only be installed by a suitably qualified amplifier service technician.

Valves [vacuum tubes], transformers, capacitors, amplification circuits found within a guitar amplifier operate at high voltages that can cause permanent injury, disability or death. Never attempt to repair, modify, test, work on or touch electronic equipment unless you are trained or otherwise qualified to do so.

Brett takes delivery of his custom Blue Mood 30W EL34 head

December 1, 2013
Blue Mood EL34 head in rough blonde tolex

Blue Mood EL34 head in rough blonde tolex

This blog showcases a customised “Blue Mood” series amplifier designed & built by the Richards Amplifier Company – Australia, for our good customer Brett Lowe. Brett has been playing guitar & bass on the local Central Coast (N.S.W.) scene for many years and was a pupil of the late, great Don Andrews, so he knows his stuff. When Brett was looking for specific voicing for his next amplifier acquisition, he came to us and we recommended a custom design based on our successful Blue Mood series amps.

Blue Mood 30W EL34 head

Blue Mood 30W EL34 head

Brett was looking for a hybrid Brit/USA voicing, so we kept the layout and gain structure of the Blue Mood amps, but substituted a pair of EL34 output valves (tubes) in lieu of the 6V6 & 6L6 family of output valves we would normally employ in this series of amps.

Blue Mood EL34 amp head

Blue Mood EL34 amp head

We rejigged the choice of output transformer and its primary impedance & also revoiced the 3-band passive EQ for a more Brit tonality, all of which contributed to the final result. The amp retains the Blue Mood features of a bypassable master-volume, and a pull-shift on the bass control for fine tuning of the bottom end, plus a “bold/vintage” switch on the rear panel to reconfigure the EL34’s to cathode-bias operation for a nominal half-power output.

Blue Mood 30W EL34 head

Blue Mood 30W EL34 head

Brett chose “rough blonde” tolex & “wheat” grille cloth to match one of his speaker cabs. Brett has acquired (and sometimes moved on) many amps over the years, including DR-Z, Swart, Bad Cat, Budda & so on, ie many of the top boutique names in the business – but his band mates are of the opinion that this is the best sounding amp he’s ever owned. We love to hear that !

rear panel - Blue Mood

rear panel – Blue Mood

You can see in the photo opposite, we have employed an output transformer by Mercury Magnetics - we are one of their recommended installers, by the way. The choice of output transformer was a key ingredient in the design of this amp. Our next project for Brett will be a replica of the “Brownface” 2×10 Vibroverb amp of 1963, once again employing transformers & choke by Mercury. We will report on this success of this project in a few weeks. Regards – Ivan.

rear view - Blue Mood

rear panel – Blue Mood

rear panel - Blue Mood

rear panel – Blue Mood

burn-in test @ the Rock God Music School Wyoming

burn-in test @ the Rock God Music School Wyoming

burn-in test @ the Rock God music school Wyoming

burn-in test @ the Rock God Music School Wyoming

Pedals & amps by Ivan Richards Audio at work in the Australian music industry

November 26, 2013
Rich Blues live on Sunrise TV CH-7 Sydney. Marcus Catanzaro NOV 2013.

Rich Blues live on Sunrise TV CH-7 Sydney. Marcus Catanzaro NOV 2013.

Rich Blues. Recording session - Slow Chase.

Rich Blues. Recording session – Slow Chase.

Class-A Distortion. Hoodoo Gurus on tour. NOV 2012.

Class-A Distortion. Hoodoo Gurus on tour. NOV 2012.

Richards 15W Expressionist amp. Recording session - Slow Chase.

Richards 15W Expressionist amp. Recording session – Slow Chase.

Richards 15W Expressionist amp. Recording session - Slow Chase.

Richards 15W Expressionist amp. Recording session – Slow Chase.

Raw Brit. Melbourne, Australia.

Raw Brit. melbourne, Australia.

Raw Brit. Melbourne, Australia.

Richards 15W Expressionist amp. Recording session - Slow Chase.

Richards 15W Expressionist amp. Recording session – Slow Chase.

Ivan’s guitars & pickups by Pete Biltoft

November 24, 2013
Ivan's '52 Tele Reissue

Ivan’s ’52 Tele Reissue

Welcome back to the blog ! Recently I discussed my intention of upgrading one of my favourite guitars – my ’52 Telecaster Reissue (late 1990’s USA manufacture), with our good customer Chris. In appreciation of some labour intensive work that we have done this past year, Chris presented me with a pair of Tele pickups from Vintage Vibe Guitars, by Mr Pete Biltoft, wound to my preferred specifications. Chris had previously had some custom work done by Pete Biltoft, with geat success. All the photos that accompany this blog were taken after completion of the upgrade work.

USA '52 Tele Reissue

USA ’52 Tele Reissue

According to the Vintage Vibe Guitars website, Pete Biltoft has a strong background in chemistry, metallurgy & precision fabrication. Add to the fact that he is guitar enthusiast, and those are pretty good qualifications for a custom pickup winder. Pete’s designs aren’t a copy of any one specific vintage pickup, but rather they are considerably enhanced & evolved designs for today’s player, while retaining the very best characteristics of the original pickup. If anything, they are somewhat over-engineered for the job at hand. It’s not often that we endorse products to this degree in these blog pages !

Ivan's '52 Tele Reissue

Ivan’s ’52 Tele Reissue

The original Fender Vintage pickups had previously been replaced by a pair of Seymour Duncans. The original neck pickup as usual was totally underwhelming, and the original bridge pickup had loads of character but a very spikey top end which rendered it unsuitable for some styles. I chose the Seymour Duncan Jerry Donahue bridge pickup and Alnico II neck pickup. The neck pickup would have suited a solo jazz guitarist but not a rock’n’roll band context, and the JD pickup curiously was not a stunning success in this guitar, although in theory it should have been. The bridge assembly is standard, but the saddles are from Acme, by Callaham, for improved intonation. The choice of saddles does have a significant impact on tone & sustain – even brass saddles from different suppliers can sound different, so every variable has some impact, however subtle that might be.

Pete Biltoft Tele neck pickup

Pete Biltoft Tele neck pickup

My preferred specification for the Pete Biltoft pickups was as follows: both neck & bridge pickups 5% overwound, both neck & bridge pickups Alnico V magnets for E, A & D poles, Alnico II magnets for G, B & E poles; G pole piece slightly raised & D polepiece raised higher to compensate for the thinner core wire in the D string of most string gauges. As an absolute minimum requirement there should be a very good balance between the neck & bridge pickups, unlike the originals. Normally I would prefer the neck pickup to have the usual cover to maintain a vintage appearance, but in this case I accepted Pete’s recommendation of no cover for maximum tone & clarity.

Ivan's ESP Ronnie Wood Telecaster

Ivan’s ESP Ronnie Wood Telecaster

The neck pickup measured 7.4K nominal & the bridge pickup measured 8.3K nominal. The pots are CTS 250K with a 0.047uf tone pot capacitor, with no treble bleed cap, and a standard 3-way switch. Pete has also supplied a 5-way SuperSwitch, to allow two additional pickup combinations – neck & bridge in series, in-phase & out-of-phase. We have yet to install this option. The documentation accompanying these pickups is the best we have seen, and Pete has done commendably well in achieving a balance between the neck & bridge positions, and also a balance between the Alnico V & Alnico II magnets.

ESP Ronnie Wood Telecaster

ESP Ronnie Wood Telecaster

The Duncan Alnico II neck will go on Ebay. But ref the Duncan Jerry Donahue bridge pickup, I had a hunch this one might work a lot better on my ESP Ronnie Wood Signature Model Telecaster – a very handsome fellow with black body, white binding & maple fretboard, a favourite look of mine. This guitar has had numerous pickup changes, mainly because of the problem of matching the neck & bridge pickups. Considering that this wasn’t a cheap guitar at all (over $2000 AUD retail, $1600 AUD street at the time of purchase), the original pickups were really average. The neck has had Fralin & Duncan humbuckers previously, and is now home to the Duncan Seth Lover Alnico II humbucker, which has a nice warm vintage (50’s) sound and is not too hot compared to a Telecaster bridge.

ESP Ronnie Wood Model

ESP Ronnie Wood Model

The bridge has previously had Jason Lollar & Jerry Amalfitano pickups, and once again getting the balance just right has always been my problem. Well, my hunch paid off – I installed the Duncan JD pickup in the bridge and together with the Seth Lover it transformed this guitar with nice vintage flavour tones, but actually although it measures 7.5K nominal, the JD pickup sounds vintage but is quite a bit hotter than vintage. Having both pickups with Alnico II magnets makes good sense, the tones & volumes match up better – the pots are CTS 500K with a 0.022uf tone pot cap, plus a 0.001uf treble bleed cap across the volume pot – this is particularly useful with the humbucker neck position.

ESP Custom Shop

ESP Custom Shop

In conclusion, as well as offering a complete valve (tube) amplifier design/build/repair/modify service centre, we also perform electronic repairs & upgrades to selected models of guitars & basses for local customers, which of course includes installing your choice of pickups & other components. Please contact by email to enquire. info@ivanrichards.com

Restoration of a vintage Sears “Silvertone” practice amp

November 18, 2013
Sears Silvertone 001

Sears Silvertone 001

This week’s blog is about the restoration to good working order of a classic item of Americana – the Sears ‘Silvertone’ guitar amplifier, marketed through the Sears Roebuck chain of stores in the USA, many years ago. This example was recently purchased by our good customer James, who is an enthusiastic collector of low powered valve (tube) guitar amps, including models by Matamp and WEM.

Sears Silvertone 002

Sears Silvertone 002

The Sears Silvertone products have become famous over the years for the entry-level guitar amps that many a successful guitarist first started playing through (in the USA & Canada). This particular model doesn’t appear to have a model number anywhere, but does have a chassis number on display. The schematic diagram is still attached to the inside surface of the cabinet.

Sears Silvertone 003

Sears Silvertone 003

The presentation of the amp is quite appealing, in the style of a vintage radio or record player. The circuit design is broadly similar to the ‘tweed’ Fender Champ models, with a single 12AX7 preamp valve, a single 6V6 output valve, and unusually, a 6X5 rectifier valve in lieu of the more common 5Y3. This last component enabled a simpler power transformer to be manufactured, not requiring an additional 5V AC winding for the rectifier valve. Obviously the cosmetics are very different to the ‘tweed’ Champs, and wouldn’t look out of place in somebody’s lounge-room of that time period.

Sears Silvertone 004

Sears Silvertone 004

The circuitry runs at somewhat lower DC voltages than the Champ, and there is less gain. The amp is very quiet – even at full volume you are playing at conversation levels. This is definitely a practice amp ! There is a commendable lack of hum & noise. This amp would probably suit the higher signal levels from a lap steel guitar. We were pleasantly suprised by the high standard of manufacture, wiring & assembly – one of the benefits of larger scale manufacture (we would assume) compared to vintage Aussie guitar amps, some of which were pretty rough & ready.

Sears Silvertone 005

Sears Silvertone 005

The Silvertone was purchased off Ebay & shipped over from the USA. Unfortunately the amp was not safe to use, with no earth and no fuse, just a 2-prong vintage USA power cord. The power transformer naturally was wired for domestic USA power only, so after some calculations & some assistance from Mercury Magnetics we were able to select a suitable replacement transformer wired for the 240V AC mains supply. The layout on this chassis is very tight indeed, and required some juggling of space to install the new transformer.

Sears Silvertone 006

Sears Silvertone 006

The 8-pin socket for the 6X5 rectifier valve had to be relocated slightly. The inclusion of a 240V primary winding unfortunately necessitates a physically larger transformer. The captive mains lead was replaced with a 3-core 240V rated lead & plug. A chassis earth point was installed, plus an internal fuse. The power supply filter capacitor was years past its use-by-date and was replaced also. This unit comprised 3 x 40uF/350V DC capacitors in a single chassis mounting metal can. Fortunately, these are being manufactured once again for the vintage amp/vintage radio market.

Sears Silvertone 007

Sears Silvertone 007

The valves (tubes) were still the original Sears labelled but actually by Tung Sol and still working fine. That’s quality for you, and we’ll never see valves manufactured to that standard again. Believe it or not, there is no input jack on this amp, but rather a short captive lead with a standard 1/4″ jack plug on the end, to insert into your guitar’s output jack. This lead was seriously crap, so we installed a decent quality captive lead. An electrical safety test, power output test and final play test and the job is complete.

Sears Silvertone 008

Sears Silvertone 008

Many thanks to Jimmy James for continuing to submit his varied & challenging projects. We still have a pair of Jim’s small WEM (UK) amps to bring back up to standard in the not too distant future. Regards, I.R.

Our 1×10 Tone Cabinet

November 3, 2013
Our 1x10 Tone Cabinet

Our 1×10 Tone Cabinet

Welcome back to the blog after a long break. We have actually been very busy designing, building, modding & repairing valve (tube) amplifiers & other rock’n’roll gadgetry, and we thank our loyal customers very much for their continued support. In this blog we showcase the latest offering in our custom range of tone cabinets, the single 10-inch speaker, semi-open-back cab. This model is obviously intended for home recording enthusiasts, and/or the guitarist who primarily plays at home.

the 1x10

the 1×10

However, depending on the choice of speaker unit, this cab will perform more than adequately at those lounge gigs. For example, the Celestion “G10 Vintage” 60W model, ie this is basically the 10-inch version of the well known G12 “Vintage 30″, produces a surprising amount of lows & low-mids loaded into this cab, and is a good choice for creating “British” type tones on a budget.

Our 1x10 Tone Cabinet

Our 1×10 Tone Cabinet

Why choose a 10-inch speaker rather than for example a 12-inch model for your home recording project ?? Consulting with guitarists who have been on the recording scene for decades reveals some interesting facts. The 10-inch speaker in fact has a more focused sound dispersion characteristic. The same comment obviously applies to 8-inch speakers.

the 1x10

the 1×10

This is all very subjective, but there is a strong body of opinion that the recorded guitar sits in the “mix” or the “track” better with the 1×10 or 1×8. But obviously to anyone standing in the room, a 1×10 cab doesn’t sound as big or impressive as a 1×12 cab, but it’s all a question of what the mic “hears” !!

the Weber loaded 1x10

the Weber loaded 1×10

Our good customer ‘Bill’, ordered this particular 1×10 cab loaded with a Weber 30W alnico magnet model, to match up with his 18W 6V6 model Blue Mood series amp, by the Richards Amplifier Company – Australia. Bill is looking to recreate the great late 50’s/early 60’s sounds from the West Coast USA, so this amp & cab are a great match.

Nothing ultimately affects electric guitar tone more than the speaker does. A speaker swap can completely transform the volume, tone & responsiveness of an amp. This is especially true in the case of a valve (tube) amp, where valves (tubes) & speakers share a unique symbiotic relationship.

Never has there been a wider choice of 10-inch speakers available, several “British” voiced models from Celestion, two great “American” voiced tens from WGS, and a bewildering number of options from Weber & Eminence. The biggest problem is – when used for their intended application, each & every one of them sounds great !

Which one to choose ??    IR.


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