On the Hunt again--Kalart Victor Projector Amp to Guitar Amp

[Platefire]

I scored this projector with a nice little audio amp inside on a flea market run the other day and thought I would share with you fellow DIY tube heads. At the flea market I just noticed it had tubes in it through the rear vent. I think it had $45 on it and I didn't know the tube configuration so after browsing around other nearby markets I decided I would come back an offer $10 for it, so I did and he took it. So that's the hunt and negotiating process.I use to be hot on the hunt for project amps when I first got into it in 2000 but have cooled off quite a bit since I've got amps stacked everywhere but it's kind of nice for old time sake to go on the hunt and have a score!

After I got it home I found it had a nice push pull amp with V1=7025, V2=12AX7, V3=6973, V4=6973 and V5=5Y3 Rectifier. Here is a few pixs and a schematic which is for a model 70-15 and mine is a 75-15 but have the same amps. As I understand it the 6973 is approximately equivalent ot a 6V6. Platefire

 

[screamin eagle]

Convert that input to a guitar input and see what it sounds like. Adjust to taste from there? Or are you planning on gutting and rebuilding? Those 6x9" speakers can sound surprisingly good in a little cabinet.

 

[Platefire]

Yelp I'm ahead of you on that one. The 1/4" phono jack was almost the perfect guitar input with the exception of a 1.5 Meg resistor in the input grid. I removed that and soldered a permanent jumper where that resistor was at. It's also got a 27K grid stopper attached to pin 7 of the 7025, I usually use a 33K for a single input but 27K is close enough.

I also got my DetoxIT out and cleaned the tube pins, sockets and pots. The 6X9 speaker sounded OK but when I rigged up a speaker cable to plug into my DIY 1-10 Cab with an Eminence Rajun Cajun in it, that was a vast improvement in overall volume and tone. The original tubes are all RCAs and seem to be pretty healthy. It's got an active Baxandall tone stack that works really good for guitar. So I'm really happy with what I'm hearing from it and will just jam on it a while as is. Here is some pixs of it pulled out of the projector housing. Platefire

 

[Platefire]

I've been jamming on this amp as is and it has a great clean tone with a active Banaxdall tone stack. I have got a mod in mind to drag some higher gain out of it. I will make that mod switchable so it can return to that nice clean tone. Platefire

 

[Platefire]

Don't look like much outside interest in this project. Anyway I did a quick you tube tonight using this amp on a blues jam. Gives you and idea what the Kalart Victor amp sounds like. Platefire

 

[dbl9]

What a great score. Very cool project! Congrats on a great conversion.
Your playing sounds great too! Nice job.

 

[Blinky]

Wow that's impressive. Great sounding amp for what, maybe 15 bucks ? Nice playing.

 

[jmclaren]

That amp sounds great! I'd leave it just as it is.

 

[Platefire]

Thanks! I got it for $10. After very much searching I finally found something nice! Yes I plan to leave it as is. If I do any mods on it, they will be switchable so it can be returned to original at the flick of a switch. It does need new filter cap cans which will be the first thing I address. I was really surprised it sounds as good as it does just stock. That doesn't usually happen with these old non-guitar amps without a lot of mods. That active Baxandal tone stack really works good on guitar. Platefire

 

[Vondre]

Hi Platefire,

I am very interested in this project as I myself just acquired a 70-15 model from a thrift store for 10 bucks. This one has what’s looks to be a Jensen alnico 6” speaker on the front panel!

What exactly did you have to modify to get it working as a guitar amp? Just the input ? I don’t plan on rehousing it, just removing the projector. I have only basic electrical/soldering skills but have been looking for a project like this to get me something to work with and gain some knowledge. Thanks in advance!

 

[mountainhick]

Sounds good!

I have this one's cousin, an RCA with 5879, 12ax7 PI, PP 6v6s, 5Y3, Maybe will just replace electrolytic caps and see before re-doing the circuit. Yours sounds nice!

 

[Vondre]

Here some pics of the one I got. Round 6” speaker, can anyone help identify?

Looks like tubes are GE and RCA, 7025 has a shield with a wire to chassis ground ?

Also there is a long spring that is seemingly just shoved into the chassis for storage maybe not sure what that is.

 

[Powdog]

Awsome! Those RCA 6973s are the cats a**. A 35uF/50v bypass capacitor across the power tube cathode resistor will give you a nice gain bump and you should have a nice little Supro-ish amp.

 

[Vondre]

Ok well it sounds pretty good for what it is, but it’s nowhere near as loud as a normal 15w. Do I have a bad power tube here ?