Truly Fantastic Tube Phono Kit - For Beginners?

J-ROB

Senior Member
I fixed a Dynaco not long ago and the FB EQ used 4.7meg/2700pf, which is a much shorter TC than 10meg/1500pf. I never saw a 10 meg resistor in any audio circuit as far as I can recall, which is why I took notice. I have a box of AB 10meg resistors that I have used as insulated standoffs. The rest will be in my estate sale.

True the gain at LF is not infinite. Maybe he was counting on well-used 12AX7s to drop the LF peak? Also the line stage is 500k input so the EQ stages are very lightly loaded and that might screw with the EQ, but my sense it would peak the LF end even more. The impedance of that 0.1 cap might also factor in somehow.

I like to think of Shindo as an old school "empirical designer," measuring what comes out of real world RIAA implementations with a generator and antique VTVM rather than running sims. And maybe he is the type of guy who would accept a couple dB variation in the curve below 50hz if everything is sounding good...I know I am.

I'd be interested in the THD coming out of that phono preamp. I would suspect it has a "strong sonic signature" to say the least.
Isn't that what people are paying big Shindo bucks to get? Well, not with this cheapskate DIY version, but you know what I mean...
 

J-ROB

Senior Member
Even for contact bias, 10 meg is overkill. 3-4.7 meg is enough. Well, I suppose I can match pairs to 0.1% and get non-skewing 5 meg grid leaks!:tongue:

I have about 60-70 left if anybody needs some!
 
Hi J-Rob,
How did you get on with your Chinese EAR834 kit?
Any comparisons between that and your bird's nest P2P phono?
Any upgrades tweaks etc that you would recommend?
best
tim
 

J-ROB

Senior Member
Hey Tim, when did you sneak in?

Turned out that my intended chassis was 1/2" too small to fit the boards and too-large toroidal PT I bought. Got a new face plate for a larger recycled chassis in the mail yesterday.

I am hours from completion on the kit but I'm engaged in wild preparation for the Munich HighEnd show next week and probably won't finish until I get back.

I'm hoping to catch Tim de P, the other Tim, there to get his take on the Chinese 834 phenomenon....that should be interesting, to say the least.
 
Hey Joe,
I'm not sure Munich is exactly fun for you and Silbatone so make sure you leave yourself enough time to have at least one beer.
I DIYed TdeP's EAR 869 amp (SE EL519s EMT thingie) and its pretty damn good so thank him for me.
And tell JC that I've just finished a Frank Blohbaum MTA amp---but still making up my mind about that one.
rock and roll
tim
 

J-ROB

Senior Member
Last year some masked Germans stuck a funnel in my mouth and forced me to ingest a beer. You know I would never allow that voluntarily..."Lips that touch liquor shall never touch mine..."

Frank Blohbaum will be at the show as well. He had a few simple preamp designs that he used to illustrate a lecture at ETF last year. Maybe I can scare up copies? He is definitely in the upper echelon of tube designers today and a very nice guy.
 

mhardy6647

Señor Member
Last year some masked Germans stuck a funnel in my mouth and forced me to ingest a beer. You know I would never allow that voluntarily..."Lips that touch liquor shall never touch mine..."

Frank Blohbaum will be at the show as well. He had a few simple preamp designs that he used to illustrate a lecture at ETF last year. Maybe I can scare up copies? He is definitely in the upper echelon of tube designers today and a very nice guy.
Well, if one's going to be forced to ingest beer, it's probably for the best that one is in Süddeutschland.
Not that I'd know or anything.
 

TubeHiFiNut

Administrator
Last year some masked Germans stuck a funnel in my mouth and forced me to ingest a beer. You know I would never allow that voluntarily..."Lips that touch liquor shall never touch mine..."
You have to watch those masked Germans. ;)
 

J-ROB

Senior Member
Baader-MeinHOF, Hardy, one F!

The other F goes on the end of Edelstoff, my favorite Augustiner Brau spring beer.

edelstoff_1_.png
But I'll be mostly researching DIY and kit preamp designs, not drinking beer and eating wienerschnitzel...
 

mhardy6647

Señor Member
Baader-MeinHOF, Hardy, one F!

The other F goes on the end of Edelstoff, my favorite Augustiner Brau spring beer.

View attachment 5977
But I'll be mostly researching DIY and kit preamp designs, not drinking beer and eating wienerschnitzel...
The irony being, of course, I checked the spelling of Baader, but trusted my memory on Meinhof.

Schade
.
 

J-ROB

Senior Member
Hey folks I just spotted this shining example of cultural appropriation: Marantz 7 phono kit.

Or, as mhardy6649 would spell it, Maarantz 7.:p

https://www.aliexpress.com/item/Hi-End-M7-Vacuum-Tube-Phono-Riaa-LP-Turntable-Preamplifier-HiFi-Stereo-Marantz-7-Preamp-Assembled

$70 shipped, assembled and ready to roll. Just hook up transformers and you're good to go.

Marantz7kit.jpg

I heard a Marantz 7 last weekend at Ijaz' house....actually it was Sid Smith's personal 7. I always liked the Model 1 a lot more back when there was a chance of picking up Marantz at yard sale prices, but the 7 is good too. This rehash has little to do with the real model 7, of course, but it was a "top five" 12AX7 preamp in my experience.

This kit uses a tube rectifier (optional hookup) rather than the selenium of the original but one could probably swap selenium in. Also, the polypropylene Sprague Orange Drop caps are wildly out of fashion these days but surely quality made stuff. I stopped using them for audio coupling in the 80s when I realized they were a bit hard sounding. They can easily be swapped out too.
The orange Sprague electrolytics are decent sounding.

Basically, this is a simplified distillation of the 7 phono stage, minus all switching and options. The board looks to have a highish output impedance so it is looking for a high impedance input to output into or I suppose one could add a source switch, high resistance volume control, and line stage in the chassis with the phono board and have a full function preamp.

What the heck, I'm buying one just to mess with. By the time it gets here via ChinoShip, I'll have forgotten I even bought it and it will be like a gift from above.

marant7circuit.jpg
 
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Salectric

Senior Member
J-Rob,

I heard Ijaz's system several years ago with the Marantz 7 so we have something in common. I seem to recall that his Marantz units had been tweaked by Sid at some point. I know the Marantz 8B amps were highly modified since they are PP 300B but I think the preamp had some work done as well. In any case, I do recall Ijaz saying he used all Telefunken ECC803S tubes which gives it a definite advantage.

Looking at the Marantz 7 schematic again reminds me that David Manley totally ripped off the Marantz 7 phono circuit in his VTL Ultimate preamp. It used the identical circuit right down to having a 510K resistor on the input in parallel with the regular 47K input resistor. And he never gave Marantz or Sid Smith credit.
 

je2a3

Junior Member
Hmmm, the name Ijaz sounds very familiar...I think I met him many years ago when I lived in the MD/DC area.
 

J-ROB

Senior Member
Salectric, Ijaz has Sid's Model 7 so I presume it has the Sid Smith mod.

I once saw a pr of Model 5s at Ijaz place and they had various distinguishing features of my old Model 5s, including weird RCA jacks installed on a metal plate, so I said "Hey! You got my old 5s!" He said no, they were Sid's personal Model 5s. I guess mine had the Sid Smith mods too. They were the best Marantz amps I ever had (2, 8, 8b etc...never had 9s).

What Ijaz says is that he had a M7 that he loved and sent it to Sid for the mod and it came back sounding worse! Eventually he got it straightened out but he and Sid became good friends as a result of the interactions.

Early VTL had very little going for it in the way of innovation. Actually, we are way beyond where the field was in the 80s and 90s, at least in terms of circuit refinement and range of topologies. Phono preamps were always boring until the internet came along and spiced up (pun) design options.

JE, you might know Ijaz...he is usually in Slagle's room at shows, including at Capital Audiofest. He and Dave have been working on juiced up Quads with integral PP 300B amps. Sounded really good last weekend.

Ijaz is also a leading Garrard 301 nut. I let him borrow my new bearing to try out while I am quaffing weissbeers in Munich.
 

Salectric

Senior Member
Joe,

I could be mistaken about the Marantz amps. Perhaps they started life as 5s instead of 8s.

When I was there, Ijaz had a pretty unique turntable setup. On a single shelf he had 2 tables---a Garrard 301 and a Loricraft/Garrard 501---and he was using the 301 as a motor pod for the 501. The motor unit for the 501 was not in use. Instead he had a long thread that wrapped around the 301 platter and the 501 platter, and only the 301 was powered. I suppose the thread provided some isolation from motor noise. The 501 had a Schroeder Reference arm and a SoundSmith modified Denon 103. That was one very musical vinyl setup.

Since that visit, Ijaz has gone through a number of tonearms. He replaced the Schroeders (he had 4 or 5 of them!) with Analog Instruments Apparition and later Analog Instruments Siggwan. Based on his enthusiasm for the Siggwan, I bought one myself and am very happy with it. At the last several CAF shows, Ijaz had some custom arms that also sounded very, very good.
 
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J-ROB

Senior Member
Ijaz is making his own arm, called "The Chunk," 1.5" rectangular ebony shaft with giant brass weights...you would remember if you saw it. Gives new meaning to the concept of high mass tonearm. Works great with DL103s. I believe it is an extension of the Sigwan concept.

Schroeder is his friend also. We are in the same audio gangs, basically.

I think he mainly listens to an 8B, not 5s. I am usually there when Slagle and a few other guys come to visit to work on the self-powered Quads.
 
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