Tubes: 1-12AU6; 1-50C5; 1-35W4

Speaker: 8″

Made by Sound Projects Company, who also made the same amp with different cosmetics for Custom Kraft.

Click pics to enlarge:

Thanks to John Davis for the great pics of Ex. 3, and to Martin Manning and all the helpful guys on the Sound Projects R203 page at http://music-electronics-forum.com/t21844/ for the schematic.  What a great community over there!


Example 2 has the original Quincy* speaker, and was on eBay in June 2010 with this description:

Here’s another of my favorite small tube practice amps up for sale. This one is a Sound Projects R203. It features 12au6, 50c5 and 35w4 tubes – same tube lineup as many small Harmony’s, Alamo’s, Kay, Lectrolab’s etc. – a 6″ Quincy speaker, 1 Volume, 1 tone and 3 instrument inputs. I estimate 3-5 watts of output. My best guess for manufacturing date is mid 60’s.

Here’s the good: I recently had this amp serviced with a new 3 stage filter cap, new power cord (2 prong) and 3 new input jacks. Everything works well and she is ready to go. I also added a piece of plywood for the back – when I got it, the back was missing. That addition made a huge difference in sound of this small (16 x 16 x 7-1/2) amp. This amp now sounds very good alone or miked. Crank the volume all the way and you get a very nice blues/classic rock sound out of it. It’s fun for practice but my personal opinion is that like most small tube amps like this, it really shines when used for recording. Cosmetically, the amp is in very good shape for it’s age. Some small scuffs in the tolex and what appears tobe a stretch in the grill cloth – It’s not a tear and I’m not sure you will be able to even see it in Pic 1.(It’s just about in the center of the cab).

Here’s the bad: Nothing really – It’s a practice amp so you won’t wake up neighbors, sustain hearing loss or get noise citations.

What else? – You could easily fit an 8″ speaker in the cab and I think a lot of 10″s would fit as well. The tubes are in good shape and replacements are cheap and available. The service work was personally done by Andy Fuchs at Fuchs Audio Technology – They are specialists in tube amp building and repair. If you haven’t seen a Fuchs Amp, I highly recommend you check them on the web.

There is not a lot of info on Sound Projects and it’s rare to come across one of these – especially in such tip-top condition. If you’re a collector or just love these small tube amps then this one is a winner. I am setting a reserve that will just cover my costs. Good Luck!

 Quincy Speaker, in Quincy Illinois, was a spin off of the DuKane Corporation in St. Charles Illinois that built conventional cone type speakers for DuKane, Zenith and other radio manufacturers. They used paper cones manufactured by Hawley Products in St. Charles Illinois. (from http://www.ionovac.com/dshistory1.htm).  Now you know.  They have been seen in other Lectrolab amps as well as this one.



21 Responses to R203

  1. Jay Hammond says:

    That’s my amp!! [referring to ex. 2, above] Since no one bought off the bay I’ve kept it and really am glad I did. For what it is, it’s very nice indeed. Seems to be holding up well and is good build quality. It’s a good little amp!

    • alexage1 says:

      Thanks for the note, Jay! It’s a small Lectrolab-world. If you have more pics, or any recordings of the amp, be sure to send them. They’ll be posted immediately for the benefit of all the Lectrolab fans out there.


  2. John Davis says:

    Man Jay i wish i would have seen your ebay post i would have bought your R203 in a second. Besides your post i saw this on ebay one time 3 years ago. No one has these amp anymore. I got one from my dad who kept it since 1965 in the basement and gave it to me when i turned 18. It was nearly mint except the multi-cap had been changed to 3 newer electrolytics.

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  5. Jon Mulhern says:

    Hey guys. A friend brought one of these to me over 15 yrs. ago as a basket case in hopes I could repair it in about 2 days since he was leaving the area permantly. I told him there was nothing I could do in that time due to my day job, overtime hrs., etc. He understood and told me he wanted me to keep it since he’d always been pleased with my repairs and mods to his amps in the past About ten yrs. ago I must’ve been bored on a Saturday and went into my basement and did some surgery on her. I remember replacing caps, reworking the power supply, new tubes and God knows what else. Plugged in, turned her on and she sang like a bird. Still got her. Coolest thing I see in this amp is it’s made the way amp like that should be made; no frills and not even a circuit board where one is not needed. Plus, I like the less popular tube array, probably an economical decision at the time, maybe still.

  6. alexage1 says:

    Phillip Lemay, a generous reader, gives us the following:

    “As requested please find attached a jpeg format image file of the schematic from the masonite back panel of my recently acquired Lectrolab R203 by Sound Projects Company amplifier. I will also note that it was equipped with a “Chicago” Jensen blue & silver label V-series 8″ speaker with the part number indicating 8 ohms impedance, which agrees with the schematic.

    Along with a new 18 A.W.G. polarized two conductor power cable (a real one – not a zip cord job), removal of the “Death Cap” (C6), new Delrin glides, stainless steel screws and bolts to replace the missing ones, and a full interior and exterior cleaning, it will also be receiving a Ted Weber Chicago Vintage series 8″ ceramic speaker. I will of course be keeping the original Jensen, with the professionally repaired tear in it that matches the tear grill cloth, so it can stay with the amp in perpetuity (hopefully) for future collectors/”Amp Heads”.

    Again many Thanks!

    With Regards,

    Thank you, Phillip! His schematic can be seen in the gallery above, captioned “Schematic from backpanel”.

  7. Ken Shalek says:

    I think I own this amp now, bought off e-bay 2007?. I changed 1 Cap with one from an old Hammond organ amp. This amp is the best sounding practice amp I’ve ever used. The tube compress like an old British amp. To my ears it sound identical to a Marshall Model 1974 18 watt plexi. I let this amp sit for 4 years because i was ignorant of tube complement. These are Radio tubes!!!. I remember turning amp on originally and got almost no volume, thinking i got ripped off!!!. I replaced 1 cap and this baby cooks..Thank’s again for this GEM..

  8. Philip LeMay says:


    I sent this message directly initially. Based on your quick reply to my first e-mail I figured I best submit this update “through channels”. Cheers! -Philip

    I have completed the re-fitting of my Lectrolab R203 guitar amplifier and I would like to relay to you some additional information that I learned as a result of my work. First off the scope of the work I did ended up being greater than I had originally anticipated (more cabinet work was needed; I will send you specifics if you would like). From that, and potentially important to those referencing the R203 information in the future, I want to note three additional points about the schematic that was on the back-panel of my amplifier verses the schematic developed by Martin Manning, et al. The M. Manning schematic is the more accurate electrical diagram of the R203 I have been working on with regard to two areas.

    Specifically the 130 Ohm, 5 Watt power resistor connected in series with the tube heater filaments indicated in the Manning schematic is present in my amp, but not indicated by the back-panel schematic. Likewise the audio output transformer secondary and one side of the speaker voice-coil do both connect to audio (chassis) ground as indicated by the Manning schematic, but again not by the back-panel schematic.

    The third point to note is the connection point of the A.C. line-to-ground filter capacitor (a.k.a. The Death Cap). The back-panel schematic indicates that this was connected post, or after, the power switch. This is how it was connected on my R203. It should however be noted that the interior pictures of the amp from which the Manning diagram was developed clearly show that the A.C. line-to-ground filter capacitor in this amp is connected pre, or before, the power switch. This is as it is drawn in the Manning schematic. I am noting here only the connection points found on two different examples of R203 guitar amplifiers. I am not covering any of the safety issues associated with this type of design. I agree George with what I have read here on the Lectrolab site that anyone working on one of these amps should do their own research and if in doubt-take it out.

    Thank you again George for the fine site!

    With Regards,
    -Philip LeMay

  9. Jon Reeder says:

    I have the R203 without tone control. I love it. I can get a very balanced and sweet clean tone or a very nice crunchy overdrive when cranked. Or I can put a tube overdrive in front of it for some more biting tone.

    When I bought it originally it had no output transformer, but I took it to a tech. who installed one for me (it was pretty pricey, considering I bought it on Ebay for around $40). Now it is perfect! I can even get it to sound great at an appropriate level in my apartment. As I have read around the net, many people seem to abhor this tube lineup. I think it is great and provides some unique complexities and a certain harmonic “softness” which isn’t present in many of the popular 12ax7 tube amps. At any rate, it provides a uniquely alternative sound when you want to play something a little different.

    Anyway, I’m glad I found your site. It’s great!

    – Jon Reeder

  10. Ken Shalek says:

    @Jon. I agree with the “sweetness” aspect. 12AX7 types get very harsh in some amps when pushed. This little Pentode tube just gets sweeter when pushed.

  11. Jeff says:

    I have one of these as well. It most closely resembles example #2 with the exception of a blue faceplate instead of black as well as more prominent “design lines” on the grill cloth. It really is a strange little amp with a lot of mystery to it. I picked it up broken at a thrift store for $5 and had it repaired for around $40. All in all, I love it. It sounds fantastic when cranked.

  12. Ken Shalek says:

    I/m selling my Sound Projects model R-203 for $120.00

  13. Olie Eshleman says:

    I have one identical to example 2! This is a great resource. I’ve had mine for 5 or 6 years now. I think I paid $60 from a local music store. My bandmates and recording buddies refer to it as simply “the magic amp”. The tone cap was replaced at some point as well as the back panel. It’s not real pretty and the tone pot seems to be dying. I’m just about start down the long road of learning tube amp repair and this will be one of my first projects. Mine has an Oaktron ceramic speaker, I imagine it’s a replacement? I’ll send some pics if anyone’s interested.

  14. JCarmichael says:

    Does anyone have a step by step guide for adding a three prong plug to the Lectrolab R200b? I just need to ensure that I wire it correctly to trust it as safe.

    Thanks in advance!

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  16. Chris Till says:

    I done bought one of these today at an auction. It’s identical to Example 2. Apparently all original. When plugged in, it emits a not unpleasant, but steady, buzzzzzzzzzzzzz. I have no idea how to approach the troubleshooting. Anybody have any free advice? Thanks, Ohio Chris

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  18. Does it make actual sound when the guitar is plugged in? Or just the buzzzzzzzzzz? You could have filter capacitors going bad.

  19. kenshalek says:

    Yep, change the Capacitors

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