Pioneer Spec-1 Preamp - Part 1

[@garynichols1502]

When I was in high school most of my friends had posters of girls on their bedroom walls. I had photos of the SPEC-1 and SPEC-2!

[@geoffreykeane4072]

Thanks Tony. I did a soldering course decades ago based I think on a NASA course. We were taught to trim the leads before soldering for high reliability. I must admit I haven’t really kept to that over time but good to see this done right.

[@__Dude_]

I was surprised that an hour had passed already. Your videos are always fascinating, no matter how long they are. The insert about how to compare transistors was also interesting, since this rig is so simple to make. Thanks a lot, Tony B!

[@jaybats7865]

I am a total novice when it comes to electronics but I am totally fascinated by it. I love vintage Pioneer audio equipment and own several vintage Pioneer receivers and several vintage Pioneer speakers because I just love the sound that they produce. That being said, I must say that I really enjoy your videos and watch them every chance that I get. You are a true professional master electrical engineer and your skills are nothing short of amazing. Thank you for the fun that I get from watching your videos! 👍

[@mackfisher4487]

What a neat project and way to enjoy my Sunday morning coffee, thanks Tony for a look like another great series. Neat power supply design with secondary fuses and wire wrap output terminals.

[@Paranimal86]

You sir have a ton of knowledge! My father is a retired electrician from DuPont... I understand some of things you speak of, but learned a lot watching this videos ! I still don’t understand most of it though haha I’ll have my dad break some of this down further thanks for the post!

[@andymouse]

Attenuator looks great, I had no idea how much they would cost but 70 quid shook me a little !....cheers.

[@jimomertz]

I don’t remember this Spec 1 series. I don’t see anything that makes it high end. It looks like all typical components in there. But I do love that era. That beautiful aluminum faceplate and nice aluminum knobs and switches are oh so nice.

[@ProdigalPorcupine]

I agree! The PCBs look like any other consumer gear of the time, really. Littered with electrolytics and ceramic caps...

[@michaelp3076]

I really liked your segway on the transistor tester. You explained it extremely well.

[@jeffadams5510]

Interesting to see those caps had to be reformed. Love the tips on soldering/clipping leads-always learn something new watching your vids. Can't wait for part two as I own one of these :)

[@marksowers5041]

That was an excellent discussion on transistor matching using a jig for testing VBE. Sure beats the expense of a curve tracer. Thank you for the tutorial!

[@FOH3663]

Very nice This particular piece, ... the era, type/style, etc., of pre-amp is likely my all time fave visual in audio electronics. The industrial design is simply superb. I also like the Fluoroscan meter era integrated amps. Visual appeal varies with people, but damn, those blue Fluoroscan meters on those units were gorgeous. Pioneer still had solid cache/reputation, and via TAD, they're engineering and R&D was second to none at that time.

[@rando434]

Great instructional video! I always look to see if you have a video on a piece of gear I own as I am rebuilding every piece in my collection because of the age now. Just finished my Sansui 990 to great success because of the videos you made on that receiver. Will start the SPEC 1 and 4 shortly. Many thanks for sharing your knowledge with those of us who want to do this ourselves but don't quite have all the know-how.

[@overload3996]

They sold the Spec 1 and spec 2 at PX in Stuttgart Germany in the real early 80s. This unit is high quality, and bad ass.

[@denveradams4909]

The Pioneer Spec-1/Spec-2 was the greatest combination of Pre-amp and power amp ever created. I purchased these while serving in the US Marine Corps on Okinawa, Japan. The headphone amplifier in the Spec-1 pre-amp was absolutely spectacular. I used the Koss Pro4/AAA headphones and listened to Genesis. I had the Pioneer JA-R1A equipment rack, Pioneer CT-F900 cassette deck, Pioneer RT-707 open reel deck, SG-9800 graphic EQ, Pioneer DT-400 digital clock/timer and a Pioneer direct drive turntable sitting on top. Later, I also invested in the Pioneer RT-909 10 1/2" open reel tape deck. And topped this system off with the Sansui SP-X11000 speaker system with 2-17" woofers per side. Awesome system! Wish I still had it. From 1978/79.

[@xraytonyb]

Koss Pro4/AAA - another thing I would love to have in my collection! One of my cousins had almost that same setup. It sounded amazing! Thanks for sharing!

[@robertweinmann9408]

Hey Marine. I spent MANY hours in the audio hobby shop run by special services at Camp Foster on Okinawa in 77/78. It was an audio paradise. I wound up buying the Sansui CA-2000/BA-2000 amp pair. I did stick with Pioneer for the CT-F1000 tape deck and PL-570 turntable which were fantastic units. I think I made a good decision as I still have the Sansui amps and they are still going strong. Semper Fi!

[@denveradams4909]

@@robertweinmann9408 That's pretty cool. I bought some of mine on base, but most of it at a Pioneer shop off base. I was on Futemna. Most of my equipment, I donated to my church back home in West Virginia to be used as the church sound system. And it was used there for many years. That PL-570 turntable sounds familiar. I wasn't sure of the model I had back then. It was stolen from me in the barracks at MCAS El Toro.

[@TY-ob7fz]

Thank You Tony. Love this series and appreciate you're covering them.

[@stephanc7192]

Looks like a very interesting power supply you go through to power the unit!

[@MichaelYates]

Excellent work, thank you for sharing

[@subsonicdeathmonkey]

Thank you for the video. I need to fire up my Spec 1 and see how it goes. I’ve been running my Luxman C-300 with the Spec 2 but the Luxman needs some love.

[@hestheMaster]

Awesome tutorial on going about fixing an ailing Pioneer amp.🔥

[@johnroberts4571]

Believe it or not..me an my younger brother found this one an the spec 2 amp at a goodwill..I paid 75 for both..bought it an had it tuned up an it sounded excellent...

[@leefarmer4212]

A close friend had one of these in or around the end of the 1970,’s,his father had got it in Vietnam,and got it fairly cheap! This bad boy would shake windows in his mom and dads home!!! I would be scared to know what one of these would cost. It was the most power I had ever listen too,at that time. I know some years later he had told me he had a transistor go bad?? The end of it was he never could find anyone around our home town who would or could work on it! As the gentleman mentioned,,these were the very top of the electronic product line. He had told me he just threw it away??? I would have loved to have had a chance at getting it!! I do know one thing he was confronted with?? This monster would get HOTT!!!

[@tubeDude48]

I would have just *replaced* those CAPs with some *Nichicon* before I ever turned it ON. But that's just me! :)

[@andrewlittleboy8532]

The attenuator is beautiful!

[@rjonzun5828]

Another excellent episode

[@stevesmyth4982]

One of the more noteable differences with the old gear is the low component density on single sided SRBP PCBs.

[@Wizardofgosz]

I would love to use one of those stepped attenuators in a vacuum tube mic preamp I just built. That would add a classy touch.

[@jutukka]

Excellent video. 👍 Those 726s seem to combine the worst qualities of both tube and transistor world; they sound like transistors, but snap, crackle and pop like bad tubes. 😀 Thanks a lot. Now I have to check all my amps and find possible faulty transistors before I can sleep well. 🥵 😀

[@williamsquires3070]

(@47:41) - All too true, Tony. This is why I recommend getting something like the Peak Atlas DCA-55 component tester (or something similar); it has three test leads, and will identify all BJT, (mos)fet, SCR, Triac, Ge/Si diodes, LEDs, and diode packages (such as those used in computer power supplies, or in the older TV sets with the sync separator “diodes”), as well as tell you the pinout, and some simple specs. These are great for testing a new part that you’re going to put in circuit to confirm the pinout is what they say it is. It’ll also identify obviously bad parts for shorts.

[@jimgardner5129]

Thank you good sir for this fantastic video. While not my area of expertise, none the less, incredibly interesting to watch. Can't wait for part 2. Just found your channel and subbed. Have you worked on any Hitachi over the years? Build quality?

[@kenkai6133]

Thank you.

[@curtismuma1931]

Very informative! Thank you!

[@Learnelectronics738]

Great Amplifier brother I like

[@jdmccorful]

Another good "journey" into the world of diagnosis / repair for discrete electronics . Being detailed oriented can make the difference in this venture. Thanks for the looksee.

[@tenmillionvolts]

I usually find a small spot of carbon between the legs of the transistor where it is leaking across. I used to use a craft knife to scrape between the legs and usually it would fix them. Not sure if it was due to the black paint on the legs but it was common on the painted / coated leg transistors

[@camillebrother7590]

Hello, I would like to know what type of synthetic grease is used at 29:38? Is this the STA - LUBE SL 3301? Thank you in advance for your response.

[@johnroberts4571]

I owned the spec 1 an the spec 2...very nice..

[@philshifley4731]

Thanks Tony. I have a feeling my Spec 1 that I bought "inoperative" due to user error. Having to go back to the preamp with speaker wires is very different from any other gear I have ever used.

[@allanredford6070]

imo pointless complication. more connection contacts to degrade signal. - no trouble to have switching on power amp. preferably relay-controlled, like on some high-end Kenwoods.

[@jamesvw769]

Thanks again Tony. 👍

[@yusdiy]

would be helpful to link the transistor jig video in the description for us newcomer or subbers whom forgotten. Are the tools you used e.g. transistor jig and cap meter searchable in your channel? If yes, ignore my questions. Great video as always.

[@theoabrams2079]

Your videos are very informative. How did you get into repairing vintage receiver ?

[@amarcy5369]

Hi Tony First of Im definitely out of my comfort zone, being a retired electrician so please make allowances for my ignorance. Would it be the case when dealing with such small resistance values , even assuming the devices are the same part No . That differences will be always present dew to the limitations of the manufacturing processes . And also the limits of the test equipment used to ascertain said values . Love your channel . I am trying to get to grips with this fascinating subject, but it can be very confusing to a novice like me. Regards Mike 👍

[@Digital-Dan]

A beauty from the day before they started writing dark gray on black.

[@rogergorrell6349]

Hi Tony, Can you comment on the amplitude of the input from the frequency generator that your putting in to the input terminals of the amplifier and how much these levels vary depending on which input it is, phonograph, auxiliary etc. Thanks, Love Watching all of your videos.

[@jackoamator3325]

Ok super film . Positive.

[@redfelipe6565]

At time 15:56 you are using a misteriuos tool to detouch cable from the board. Would you please describe me that tool and possibly indicate how can I buy it. Thanks for all your video! Like.

[@boying100]

It was just a wire unwrapping tool

[@redfelipe6565]

@@boying100 Many thanks Sir, the suggestion was very useful for me. I find the tool on amazon and also e-bay.

[@gavincurtis]

Oh my! is what I said upon its mass being a lone preamp.

[@nickfrench7372]

Nice turntable to turn a heavy unit around,,,rather than having to pick it up awkardly.

[@PeterMilanovski]

Oh! A beautiful Japanese made soder sucker with the silicon tube on the end of it! Have you thought about putting a silicon tube on your vacuum pump soder sucker? I have always wanted to know if it improves the suction! I have one of those large goot type soder sucker that has the melting tip on it. Although I think that with a piece of silicon tube on the tip of it will give it more suction power to pull out the soder from the other side...

[@bobbybiggs4348]

It would probably improve suction but it'll do nothing for thermal transfer to melt the solder.

[@sonotdown998]

I do a lot of desoldering. The $245 it cost to switch from my “beautiful” Japanese solder sucker to the (also Japanese) Hakko FR301 desoldering gun is some of the best money I’ve ever spent. And, yes, putting silicone tubing on the Hakko’s tip would be about as useful as putting silicone tubing on the tip of your soldering iron-that is to say, useless.

[@bobbybiggs4348]

@@sonotdown998 that's what I thought

[@ionelsili]

Hi! Can you tell me please what tool you use in the minute 15:55? Thank you!

[@peterschulze2082]

I wanna know too!

[@BjornV78]

45:43 My guess is that they get noisy because of corrosion gets inside due the capillary effect, and that gives a path for moisture.

[@Wizardofgosz]

Have you ever posted your list of replacement transistors for the parts used in vintage gear?

[@mdzacharias]

Pretty sure the tarnish on the transistor leads is the source of the problem on those 726's. Often works it's way into the semiconductor element itself. Sometimes the tarnish is so bad it actually bridges between the leads at the transistor body. The 12voltvids guy had one that was "fixed" by cleaning the tarnish between the legs at the transistor body. Not the way I would have done it but the guy's kind of a hack anyhow.

[@dwgwnr1969]

Yeah I saw that video

[@Gerrit-Max]

Is there a way to match transistors without the expensive test gear ? I'm planning on doing a recap on my Pioneer SA7500 soon and it may need a few transistors replaced to as the tone control section doesn't work properly any more plus I'm starting to get some other problems to lately.

[@funnlivinit]

Mr. Carlson's Lab has a tutorial on that subject.

[@Dutchamp]

That eizz volume regular is nice but. If you just open up the volume to let's say 4th step in early steps then the first 4 resistors are not in series in the signal path the other 20 resistors are in series with the signal path. Just like dact it is the same wrong regular. I made a Elma switch like dact use. 4 decks 2 for right and 2 for the left channel. In each 2 rotaries I placed 3 resistors logarithmic overall resistance I used a special 150k ohm you can use 50 or 100 doesn't matter the way I made it it is always 2 resistors in series between them per step is one resistor going to earth. So it acts like a voltage devider with 3 resistors. Benifit is there are only 2 resistors per step per channel in series in the signal path and only one parallel to earth. Greatest benifit is the impedance in and out stays within 3% (1% of each resistor) So my volume regular has got 144 resistors stored but only 2x 3 in use per step. If impedance is within 3% the tone of the volume doesn't change one bit. Bass mids and treble sounds very even from 300mV to 10 volts out of my pre amp. With help of my friend who is electronic engineer. Back in 1992 we made this volume stepped regulater and stil working great till this day. 28 years later think course of the gold plated contacts. Back in 1992 dact didn't made them yet and it costed me about 210 gulden in Dutch money, 74 euro todays money so kind of cheap. And 1% resistors at E96 where cents back then now they are euro's per piece. But your Chinese will be far better then a Alps. Nice video again.

[@paulpaulzadeh6172]

Hi Tony Wonder why you don't use MAT03 from analog devices , need some simple modification

[@philshifley4731]

I was hoping to see how the voltage selector jumper is wired. I can just barely see it it at the bottom of the screen. I then noticed Xraytonyb is also working from a schematic that does not show this tranny and switch combo. My switch is buggered up and needs a rewire. A clear photo or the right schematic is very much needed. Can anyone help me?

[@russellhltn1396]

I'm unclear as to why the old volume control is ruined. I understand the shaft came out, but why can't it be put back in and secured properly so that it feels right?

[@FOH3663]

Thinking the same thing ... but either way I sure like the idea of a new Stepped Attenuator as opposed to the old pot.

[@andrewlittleboy8532]

It's a shame Pioneer always used them horrible spring clips speaker terminals.

[@longislandcerealkiller6385]

I believe that mitsubishi made the spec one on there hi end equipment

[@allanredford6070]

stepped attenuators had nothing whatsoever to do with digital, in design, or functionality, as said they are a switch between discrete resistors, to be clear. Alps have good reputation, later used laser-trimmed miniature resistors, db accurate capability (certainly on Nakamichi) also good on hi-end Kenwood. good vid!

[@lewiskhan9825]

hi can you make a video of you personal collection

[@justincase3880]

got the shaft ...

[@parttime9070]

Years ago I saw the whole Spec-1system in this guys living room, Reel to reel, preamp, a few amps, tuner, tape deck.. There had to be at least 10 units.. Funny thing to me was his speaker's were horrible sounding AR's..

[@bugdrvr]

I have seen a few systems where it seems like the person just bought what was fancy or popular without actually worrying too much about sound quality. Years ago I was at a bosses house where he had a full Mc system driving gigantic, two cabinet Electrovoice PA speakers. He only seemed to be concerned with how loud it got so it definitely served him well. At full volume I bet you could have used those horns to peel paint if you aimed them at the walls.

[@philshifley4731]

Anyone know what is the name of the tool used for unwrapping wires from the pins and what is the most common size needed for vintage gear in particular Pioneer? Anyone have a source for this tool.

[@rando434]

It's called a un-wrap/re-wrap wire tool. I got mine on eBay..look for a good used one as some of the new ones can be expensive. In one of Tony's other video's, he shows how you can make one. I don't remember what gauge wire was commonly used on Pioneer gear of this era..maybe 20-22 gauge?...most of the ones you come across will work on those sizes.

[@veliborzivic4471]

What happened with part 2?!🤔

[@kevinbeckenham3872]

Put bit some super glue or epoxy resin type glue that should fix spindal in the potentiometer

[@Macmini2035]

I’ve got a onkyo integra m-508, I took that apart to clean the pots but never got around to finishing it. It is in original condition, I would love to give it you and have you make a video of the repair and reassembly. I would ship it to you and it’s yours to keep, I’ll even cover the shipping cost

[@SimonEGab]

👍🏻👍🏻👍🏻👍🏻

[@seanobrien7169]

Electronics comments are even funnier than political comments!

[@johnnytoobad7785]

Those two PS caps should be replaced just based on their age. I never liked the idea of the pre-amp also acting as a speaker selector.

[@antigen4]

RIDICULOUS parts count! i only have maybe 1/10th as many components in my preamps

[@jonathanroche3835]

Sorry to ask here on this specific video but your community isn't available for me to ask dumb questions like this. I need to replace a smd r025 and it seams like amazon prices are silly and Alibaba will take forever to get here can you or anyone who sees this post, recommend an American website from which I can order from,. One were I can order just a handful from and not get jacked on price. Please and Thank you for your time.

[@williamsquires3070]

The problem with the stepped attenuator is that it’s a sealed unit; when the switch contacts eventually corrode, there’s no way to get contact cleaner in there. Of course, in all fairness, I’ve seen some pots that are guilty of this “feature” as well. 😏

[@Wizardofgosz]

I see screws. That unit looks like it will open up.

[@joemeatball1080]

Weird how this dude rambles on for minutes about sound quality concerning resistors etc. then uses an cheap ass eBay chi-com volume control.....hahahaha