Soundcraftsmen RA7501 Amplifier: Vintage Audio Review Episode

[@francesco9953]

Great gear! I have now a soundcraftsmen Pa 5001, a ps audio 4.6 preamp running a pair of Dahlquist dq10, and I have to admit that is a great amplifier! I agree that is a little bit noisy when on, but the sound it puts out is phenomenal!

[@vintageaudioreview]

The PA5001 is going to be pretty much the same sounding amp as the RA7501, and that little thump is just when first powered on, at least for mine. Have not heard your speaker, but imagine that the combo you have works well like you said- thanks for taking the time to comment!

[@scottbennett3119]

Great review! Still working fine after 40 + years. I used to see ads for Soundcraftmen in Stereo Review all the time; I remember Julian Hirsch reviewing one and giving it high praise. This review brought me there again. Thanks!

[@vintageaudioreview]

Thanks so much and I am glad it brought you a good memory. We both enjoyed Julian Hirsch. We must be close in age. that was the Oct 1981 Stereo Review and he actually di the full monty RA7503 (I would probably spring for one if I could find one locally for a great price).

[@gtric1466]

Had a Soundcraftsman EQ back in the 70's - 90's. worked great never seemed to have any phase issues. Friends would come over listen to vinyl and loved the sound.

[@vintageaudioreview]

Glad the SC EQ worked good for you. I may pick one up someday as I thought they were pretty neat. Thanks for sharing!

[@Douglas_Blake_579]

Used to maintain a bar sound system with 3 of these in the rack. One word ... DAYMN!

[@vintageaudioreview]

As always, thanks for sharing your experience, Douglas. I am guessing that they never acted up for you unless somehow beer was spilled inside them.

[@hugogaldames4156]

I have one of these that need fixin'. But most techs not familiar with these...? I can't trust them. Don't know what to do.😢

[@vintageaudioreview]

@@hugogaldames4156 Thanks for the comment. If you were near me I would suggest bringing it in.

[@Douglas_Blake_579]

@@vintageaudioreview I had to do some minor service over the years, they were pushed hard 6 nights a week for 8 hours at a time. All considered they stood up remarkably well.

[@Douglas_Blake_579]

@@hugogaldames4156 Best bet ... get online and find a copy of the service manual. Most techs can work with that to provide proper repairs.

[@v12alpine]

What a monster of a 2-ch amp! I recently had a california audio labs MCA2500 on my bench a few times (unfortunately!) due to low level power supply issues which finally got sorted out. It's putting out a steady 550 watts or so at 8 ohms into all 5 channels. 20 output transistors per channel. Your monster amp reminded me of it lol. Wish I had the tools to measure the THD and such. I bet the dampening factor is pretty good given the massive output sections.

[@vintageaudioreview]

Thanks for sharing. That MCA2500 is quite a beast if it is doing 500w/8ohms x5! Damping factor is probably >50 I would imagine..

[@TheBerdaguer]

I noticed you also have a Crown Sa-2, Which one is the better amp the Crown or the soundcraftsmen?

[@vintageaudioreview]

Thanks for the question. I no longer own the SA2. Once I got the MC352 I sold the SA2. Don't think you would hear much difference in the sound between them, if anything other than the fan on the SA2 in a quiet room with the music playing real low. The LED display on the SA2 is nice. The quality on both of them is very good. The RA7501 is a backup amp now, resting on a shelf.

[@chienminchang40]

Wow, that me think about long time ago just like you say 40 years ago, on that time $890 is expensive. I purchase Hafler DH 500 kit much cheaper .

[@vintageaudioreview]

Thanks for the comment! The difference in price meant you had to build the amp as a kit, which not everyone can do. I hope to be testing a Halfler amp before too long.

[@chienminchang40]

Yes, you are right . I am the electronic technology school student on 1976, build a lot transistor amplifier. Hafler used JFET transistor is new technology. Dynaco kit only 60w per channel, so I pick DH 500 . still keeping now.

[@vintageaudioreview]

@@chienminchang40 Glad you still have the DH500. I am almost done with a video on the Dynaco Stereo 120, which I think is the one you were referring to- it will be out in about a month.

[@BradCody-tl5cf]

Does this amp use mosfets?

[@vintageaudioreview]

Thanks for the question- it uses bipolar transistors for its outputs and there appears to be a triac and scr in the power supply

[@AlainDumasblogphoto]

I used to sell Soundscraftmen audio back the late 70's and early 80's, to me the were gutsy and better sounding than SAE, I remember driving Hartley's top of the line speaker that had a 36" woofer, what a sound. They also had the preamp-equalizer, it was to me not as refined as the amps. I till have the vinyl equalizer test record. Those were the days.

[@vintageaudioreview]

Thanks for much for sharing! I can't imagine how a 36" woofer would sound... Did you bring up their "shorting the outputs together" testing? I always liked the looks of SAE gear and their parametric EQs were cool. Hopefully one day I will get an Sae piece in. I liked the SC equalizers or even the preamp/eq's- think they called them a scanalyzer and would use the test record you have. Maybe one day I will come across a deal on one of them.

[@AlainDumasblogphoto]

@@vintageaudioreviewWe did not have the "kit" in store. The Hartleys had a very British, refined but because of the size the were sounding like the big 2X15" woofer JBL pro monitors. SAE parametrics were very good for specific issues in a room, almost like the McIntosh room corrector. I started in pro sound, doing local shows at an auditorium and eventually became the soundman for many shows and recordings. Then for income stability, worked as a salesman in audio stores. Did both for a while. To me one of the best amp out there, then, was the Crown DC300A, tough, still could deliver the nuances of Hi-fi equipment and recordings. That was our prefered amp for demos on Kef 105 and BW DM 6(crappy speaker for the size and price). Tried many amps over the years and that one always made me smile(DC300A). That one made JBL L300 sing. Those were the great days of Hi-fi. I always enjoyed high wattage Marantz amps, more than Pioneer. Harman-Kardon Citation 16 was nice sounding but not gutsy enough for lower octaves. McIntosh, sold that for a while, it is hard not to like the brand, sound and look. Tattooed for life for the brand. Keep it up!

[@vintageaudioreview]

@@AlainDumasblogphoto One of the nightclubs I DJ'd at had a pair of DC300a, though one of them died. Old crown gear is great. I never forgot the KEF 105's because of that LED. Sounds like you have some interesting tales to tell. I agree about McIntosh and have some upcoming reviews on them. Not familiar with the BW you mentioned.

[@AlainDumasblogphoto]

@@vintageaudioreviewI remember doing demos with the Soundcraftmen amp on Roger LS 3/5a, no one believe they could go low, they did to 32hz with this amp. Fun time. Audioanalyst, a pro shop back in the days, had Crown made modified DC 300a for him, he used it for his 2 way JBL 4560, so the amp was 155 on one channel, 80 on the other, so all of his speakers were bi amped with a built-in electronic crossover in the amp. One store I worked for had a basement room, we had the IMF Reference TLS and we drove it with the Luxman M-6000 and C-1000 preamp, Michell Transcriptor turntable, Teac 3340 reel to reel, listening to Direct to Disc, Lincoln Mayorga playing organ, the whole building shook. One day a neighbor called the police, was under the impression an explosion occurred. Thelma Houston, again direct to disc, I got the Music in me, ouch, when she starts singing, with the beat, it was amazing. That vinyl was made with the TOTO's musicians gang. I could go on and on. Last one for the day, an audiophile in the suburb had a house build, with housing in the basement for two EV 30" for the bass, made in concrete. Did not wait for it to cure. After 3 months of extreme bass, the foundation cracked, could not be repaired, the house was scraped.